B

Babbling.

Speech-like vocalization; usually occurs at 6–7 months of age.

Babinski reflex.

Developmental reflex elicited when a sharp object is stroked backwards along the sole of the foot, causing a child’s big toe to flex upwards and the other toes to fan out; usually disappears at 8–12 months of age.

Basic emotions.

A set of emotions related to the evaluation of an entire situation or its individual aspects; includes joy, grief, fear and anger; also called primary emotions; see relational emotions and self-conscious emotions.

Basic needs, Primary needs.

Needs associated with survival.

Batten disease, Juvenile neuronal ceroid lipofuscinosis (JNCL).

Genetic autosomal recessive disease; neurodegenerative disorder with blindness at age 5–15 and development of childhood dementia with decline in cognitive and motor functions.

Behavioral disorder.

All forms of behavior that are socially unacceptable in one way or another, such as running away from home, screaming, cursing, messy eating manners, bed-wetting, ritual behavior, excessive dependency, poor emotion regulation, aggression, fighting and bullying.

Behavioral genetics.

The study of how genes and the environment affect the development of characteristics such as intelligence, temperament and personality.

Behavioral state.

The main states of sleep and wakefulness in newborn children.

Behavioral phenotype.

Characteristic pattern of motor, cognitive, language and social characteristics that seem to be related to a known genetic syndrome or the presence of one or more genes.

Behavioral system.

Innate system shaped by evolutionary factors; activated under certain conditions and terminated under conditions other than those that activated it; the function of a behavioral system is the likely outcome of the behavior.

Behaviorism, Behavior analysis.

Group of psychological theories that emphasize the influence of the environment to explain developmental changes.

Big five personality traits.

Five traits frequently used to describe personality: agreeableness, conscientiousness, extraversion, neuroticism (emotional lability) and openness to experience.

Body image.

The subjective image of one’s own body.

Bowlby-Robertson syndrome.

The typical sequence of reactions among infants who are separated from their caregivers: initial protest followed by despair, and finally, if separation remains prolonged, detachment; see attachment.

Bulimia.

Eating disorder involving binge-eating and “countermeasures” against food intake such as intentional regurgitation or use of a laxative; see anorexia nervosa.

Bullying.

Negative actions, such as teasing and physical or verbal aggression, that are repeated over time and directed toward one or several individuals; direct bullying consists of open attacks on the person being bullied, while indirect bullying entails social exclusion.

C

Canonical babbling.

The most basic or simple form of babbling.

Caregiving system.

According to Bowlby, an innate behavioral system that triggers caregiving behavior in adults.

Case description, Case study.

Study that involves the detailed description of certain characteristics or developmental processes in a single individual.

Cataract.

Eye disease that results in the gradual clouding of the lens.

Causality, understanding of.

Understanding of the causal relationship or connection between actions and their consequences; the fundamental connection between things; see physical causality and psychological causality.

Cell death.

Selective loss of cells during the first years of life due to maturation and experience.

Cell differentiation, Cell specialization.

Process by which a cell achieves a more specialized function.

Cell migration.

The movement of cells to another location that occurs during fetal development.

Centering.

Focusing attention on specific aspects of a situation or an event; see decentering.

Cerebellum.

Part of the brain located behind and below the occipital lobe of the cerebrum, lying at an angle between the latter and the continuation of the spinal cord in the skull (medulla oblongata).

Cerebral palsy.

Impaired muscle function due to prenatal or early brain damage. Characterized by paralysis, poor motor or postural coordination, and increased or varying muscle tension.

Checklist.

Questionnaire or interview with specific observational categories, questions or statements answered by an individual respondent or by others; often used to assess the development of an individual in one or more areas.

Childhood.

Age 1–12 years.

Child-directed speech.

Adults’ and older children’s adaptation of pitch, intonation and syntax when talking to infants and toddlers.

Childhood amnesia.

Describes the inability of older children and adults to remember experienced events that took place during the first 2–3 years of life.

Chromosomal abnormality.

Change in the number or structure of chromosomes.

Chromosome.

Thread-shaped formation in the cellular nucleus that carries genes; always occurs in pairs, with 23 pairs in human beings.

Class inclusion.

Refers to a class or category that is part of another class or category; essential feature of a hierarchical structure.

Classical conditioning,

see conditioning.

Clinical Method.

Piaget’s term for the combined use of experimental tasks and interviews in the study of child development.

Cognition.

Thinking or understanding; includes some type of perception of the world, storage in the form of mental representations, different ways of managing or processing new and stored experiences, and action strategies.

Cognitive behavior analysis.

School within the behavioral tradition built on the basic premise that development is a cumulative learning process, and that learning forms the basis for most individual differences between children; also emphasizes the importance of models and observational learning, and cognitive processing and regulation of own behavior; also known as social learning theory.

Cognitive profile.

The profile or pattern of performance in various cognitive areas.

Cognitive structure.

Complex structure of mental representations and processes that forms the basis for thoughts, actions and the perception of the outside world; evolves and changes throughout development.

Cohort.

A group of individuals who share a defining characteristic, such as the same year of birth, and thus experienced certain historical events at the same age.

Collaborative play.

Form of group play in which children take on complementary roles and tasks.

Collective monologue.

Piaget’s term for children’s egocentric speech or private speech.

Collectivist society.

Emphasize social values and the individual’s responsibility and place in society; see individualistic society.

Color constancy.

Ability to recognize a color under different lighting conditions; see form constancy and size constancy.

Communication.

Intentional conveyance of thoughts, stories, desires, ideas, emotions, etc., to one or more persons.

Communicative intention.

Intention to convey a thought or an idea, direct others’ attention at ideas or conditions in the outside world, or get others to do something specific; see communication.

Comparative psychology.

A branch of psychology concerned with the study of animal behavior, in developmental psychology often by comparing the developmental pathways of humans and animals.

Concept.

Mental representation of a category of objects, events, persons, ideas, etc.; see extension (of a concept) and intension (of a concept).

Concrete operational stage.

According to Piaget, the third of four stages in cognitive development, approximately age 7–11; see formal operational stage, preoperational stage and sensorimotor stage.

Conditioning.

The learning of a specific reaction in response to specific stimuli; includes classical and operant conditioning. In classical conditioning, a neutral stimulus is associated with an unlearned or unconditioned stimulus that elicits an unlearned or unconditioned response, eventually transforming the neutral stimulus into a conditioned stimulus that elicits a conditioned response similar to the unconditioned response. In operant conditioning, an action is followed by an event that increases or reduces the probability that the action will be repeated under similar circumstances; see reinforcement.

Conformity.

The adoption of other people’s attitudes and behavior due to actual or perceived pressure from them.

Connectionism.

Theory within the information processing tradition; based on a model of mental functioning by which external stimulation leads to various activating and inhibitory processes that may occur sequentially (following one another in time) or in parallel (simultaneously); knowledge is represented as a pattern of activation and inhibition, and new networks give rise to phenomena that differ qualitatively from the processes from which they emerged; see also emergentism.

Conscience.

Emotional evaluation of one’s own actions, often involving feelings of having done something wrong; closely related to shame and guilt.

Conscientiousness.

One of the big five personality traits; see agreeableness, extraversion, neuroticism and openness to experience.

Conservation (in cognition).

A form of mental constancy; the ability to understand that the material or mass of an object does not change in mass, number, volume or weight unless something is taken away or added, even if external aspects of the object appear changed.

Constancy (in cognition).

The ability to understand that the attributes of objects and people remain the same, even if they seem to have changed, for example due to a different viewing angle and lighting conditions; see color constancy, form constancy, object permanence and size constancy.

Constraint (in development).

The organism’s resistance to change and adaptation to new experiences; often used in connection with the nervous system; see plasticity.

Constructive play.

Form of play that entails that children construct something, such as a Lego house or a clay figure; may be performed alone or together with others; see exercise play, group play, rule-based play and symbolic play.

Constructivism.

Psychological theories based on the notion that an individual constructs his or her understanding of the outside world; see logical constructivism and social constructivism.

Contingency.

Dependency between events; an event follows after the presence of a particular stimulus or action.

Continuity (in development).

Development in which later ways of functioning build directly on previous functions and can be predicted based on them; see discontinuity.

Contrast principle (in language development).

Refers to children’s assumption that every new word has a different meaning from the words they have previously learned.

Control group.

Group of individuals that is compared with an experimental group as similar to the control group as possible in relevant areas, but not exposed to the experimental variable.

Controversial children (sociometry).

Children who are both accepted and rejected by their peers, and may appear active, aggressive, destructive and angry, or as socially withdrawn; they can also be helpful, cooperative and assume leadership, and at times display socially sensitive behavior; see neglected children, neutral children, popular children and unpopular children.

Conventional morality.

According to Kohlberg, the second of three main stages of moral development, in which children emphasize other people’s values, attitudes and possible reactions to an action being considered; see post conventional morality and pre-conventional morality.

Cooing sounds.

The first sounds produced by an infant that do not resemble crying, typically consisting of repeated vowel sounds.

Cooperative learning, Collaborative learning.

Two or more children solving problems together.

Core knowledge.

In nativist theory, the innate abilities that form the basis for further perceptual, cognitive and linguistic development.

Correlation.

Measure of the degree of covariation between two variables, ranging from

-1.00 to +1.00; values close to 0.00 show a low degree of correlation; a positive correlation (+) means that a high score on one variable is associated with high score on the other; a negative correlation (-) indicates that a high score on one variable is associated with a low score on the other.

Correspondence (cognitive).

In Piaget’s New Theory, the perception of structural similarity that provides a basis for comparing people, objects, events, actions, etc.; see morphism.

Cortex.

The outermost, folded layer of the brain; phylogenetically the most recent part of the human brain.

Cortisol.

Hormone that usually increases when an individual experiences stress.

Criterion-referenced test.

Test in which the various tasks are arranged in such a way that the score reflects how far an individual has advanced in mastering skills within a specific area; see norm-referenced test.

Critical period.

Limited time period in which an individual is especially susceptible to specific forms of positive or negative stimulation and experience; if the stimulation or experience fails to take place during this period, a similar stimulation or experience later in life will neither benefit nor harm the individual to any appreciable extent; see sensitive period.

Critical psychology.

Theoretical tradition influenced by radical social constructivism and women’s studies, as well as postmodern sociology and psychoanalytic interpretation; challenges the idea that regular developmental features have a biological basis.

Cross-cultural developmental study.

Study comparing children who grow up in different cultures in order to map the importance of genes genetic and environmental impacts in the broadest sense.

Cross-sectional study.

Research method that traces a developmental change by comparing children at different ages; see longitudinal study.

Crystallized intelligence.

Ability to solve problems that require cultural and personal knowledge acquired through experience, such as vocabulary or factual information; see fluid intelligence.

Cultural tool.

According to Vygotsky, a skill that has developed through generations in a culture, and that is passed on to children, such as language, the numerical system or calendar time.

Culture.

The particular activities, tools, attitudes, beliefs, values, norms, etc., that characterize a group or a community.

D

Darwinism.

Evolutionary theory based on the premise that all organisms at a given moment in history have evolved from earlier organisms based on the principle of natural selection: offspring with attributes well adapted to the current environment are most likely to mature and reproduce, thereby passing on their own attributes to the next generation.

Decentration.

Ability to perceive other perspectives than one’s own and consider several aspects of a situation at the same time; see centering.

Declarative communication.

Form of communication with the sole purpose of providing information and direct someone else’s attention at something, such as a person, an object or an idea; see instrumental communication.

Deductive reasoning.

The process of ascertaining whether a statement is true or false based on a given premise; drawing conclusions about a specific case based on general principles; see hypothetical-deductive reasoning and inductive reasoning.

Defense mechanism.

In psychodynamic theory, unconscious mental strategies for dealing with inner psychological conflicts and reducing anxiety that follows the drives and impulses of the id and threatens control by the ego.

Deferred imitation, Delayed imitation.

Deliberate repetition of another person’s action at some later point in time; see immediate imitation.

Deictic gesture.

Pointing gesture; gesture that directs others’ attention at something in the environment without naming it.

Dendrite.

Short, branch-like extension of the cell body that receives impulses from surrounding nerve cells, muscle cells or glands under certain conditions.

Deoxyribonucleic acid (DNA).

The basic building block of genes, comprised of long spiral-shaped and sequential threads of introns and exons. DNA provides the blueprint for ribonucleic acid (RNA), which performs a number of cellular functions, controls the production of new proteins and triggers chemical reactions in the body.

Dependent variable.

The outcome, conditions resulting from variation in the independent variable.

Desegregation (education).

The reintegration of a child into an ordinary preschool group or school class after the child has received special education outside the ordinary school system; see segregation.

Detachment.

Discontinuation of an attachment relationship due to prolonged or permanent separation; see Bowlby-Robertson syndrome and attachment.

Determinism.

The view that the actions of an individual are predetermined.

Development.

Changes over time in the structure and functioning of human beings and animals as a result of interaction between biological and environmental factors.

Developmental disorder.

Disorder that is congenital or appears in infancy or childhood without the presence of external injuries or similar.

Developmental pathway.

One of several possible courses of development within the same area or domain.

Developmental phase.

Time period central to a particular developmental process.

Developmental psychopathology.

Multidisciplinary tradition among researchers and practitioners with a basis in developmental psychology; attempts to identify and influence the processes that underlie various psychological disorders, founded on assumptions about vulnerability and resilience in children, and risk and protection in the childhood environment.

Developmental quotient (DQ).

Standard score in developmental tests; corresponds to the intelligence quotient (IQ) in intelligence tests.

Developmental reflex.

Early motor reflex that normally disappears within the first year of life.

Dialectical reasoning.

The process of basing decisions and conclusions on dialectical reflection or argumentation.

Diary Study (in research on children).

Research method based on parents’ written record of their child’s actions or utterances.

Difficult temperament.

According to Thomas and Chess, temperament characterized by a tendency to withdraw in new situations, general negativity, strong emotional reactions and highly irregular sleeping and eating patterns; see slow-to-warm-up and easy temperament.

Disability.

The difference between an individual’s abilities and the demands of the environment.

Discontinuity (in development).

Development in which new functions are associated with qualitative differences rather than merely a quantitative growth in previously established functions, and where the effect of past development can be altered by subsequent experiences; see continuity, heterotypic continuity and homotypic continuity.

Disengaged parenting.

Parenting style that does not place high demands on the child and in which parents show little responsivity; see authoritarian, authoritative and permissive parenting style.

Dishabituation.

Increased response to a new stimulus or aspect of a stimulus following a reduction in response intensity due to repeated presentation of a stimulus; see habituation.

Distinct emotions.

According to Tomkins, the assumption that children are born with a certain set of different emotions.

Dizygotic twins, Fraternal twins.

Twins resulting from two separate fertilized eggs and sharing 50 percent of each other’s genes; see monozygotic twins (identical twins).

Domain.

A delimited sphere of knowledge; an area in which something is active or manifests itself.

Domain-general.

Abilities and skills that include most domains of knowledge; see domain-specific.

Domain-specific.

Abilities and skills within a specific domain of knowledge; see domain-general.

Dominant gene.

Gene that is expressed even though it is inherited from the mother or the father alone, and resulting in a characteristic that will always be expressed; see genomic imprinting and recessive gene.

Down syndrome, Trisomy 21.

Syndrome that causes varying degrees of intellectual disability; caused by an error in cell division that results in a partial or complete extra copy of chromosome 21.

Dynamic assessment.

The mapping of children’s cognitive abilities by recording how much progress they make in the solution of a certain type of task after having received specific help and training for a given period; see Learning Potential Assessment Device.

Dynamic system (in development).

A system of nonlinear self-organizing and self-regulating processes in which qualitatively new functions occur as an integrated result of interaction between subsystems that may have different developmental rates.

Dyslexia.

Severe reading and writing disorder, despite adequate sensory and intellectual abilities and appropriate training; see learning disorder.

Dyspraxia.

Partial or complete inability to perform voluntary movements.

E

Easy temperament.

According to Thomas and Chess, temperament characterized by an overall good mood, regular sleeping and eating patterns, easy adaptation to new situations, a positive attitude toward strangers, and moderate emotional reactions; easy to calm down when agitated; see difficult temperament and slow-to-warm-up.

Echolalia.

Meaningless repetition of what other people are saying, or of things heard on radio or television.

Ecological psychology.

According to Bronfenbrenner, a model of child development whereby developmental conditions are determined by the complex interaction between various social systems that impact one another; see exosystem macrosystem, mesosystem and microsystem.

Ecological validity.

The extent to which an observation is representative of the natural environment of the individual being observed; see concurrent validity, construct validity, external validity, internal validity and predictive validity.

Ego.

In psychoanalytic theory, one of the three parts of the human psyche; its purpose is to regulate the drives and impulses of the id in relation to the realities of the world and the limitations of the superego.

Ego ideal.

In psychodynamic theory, an individual’s objectives and frame of reference for acceptable and socially desirable behavior; the person an individual desires to be.

Ego psychology.

Branch of psychodynamic psychology that emphasizes the autonomous role of the ego in the development of personality, independent of drives.

Egocentric speech.

According to Piaget, verbal communication that fails to take into account the other person’s perspective, see private speech.

Egocentrism.

Tendency to interpret events from one’s own perspective; partial or complete inability to distinguish between one’s own and other people’s perspective.

Electra conflict.

According to psychoanalytic theory, a genetically-based psychological conflict rooted in the idea that girls are sexually attracted to their father, and experience the mother as a competitor for the father’s affection; equivalent to the Oedipus conflict for boys.

Electroencephalography (EEG).

Method to record the electrical activity of the brain by means of electrodes attached to the exterior of the skull.

Embryonic period.

Weeks 2–8 of prenatal development; see germinal period and fetal period.

Emergentism.

Theoretical approach related to connectionism; based on the premise that existing elements and processes interact to give rise to new phenomena that are qualitatively different from the elements and processes they emerged from.

Emotion.

A state caused by an event important to the person and characterized by the presence of feelings; involves physiological reactions, conscious inner experience, directed action and outward expression.

Emotion regulation.

Implicit and explicit strategies to adapt one’s own emotional reactions and those of others in line with social and cultural conventions, especially in regard to the expression, intensity, duration and contexts in which they arise.

Emotional attunement, Affect attunement.

A state in which a person is sensitive and responsive to the emotional state of another. According to Stern, a process by which the caregiver “mirrors” the experiences of the child without using language and allows the child to understand how he or she is perceived.

Emotional competence.

The ability to understand one’s own and others’ feelings, and to make use of and regulate the expression of one’s own emotions in problem solving and social interaction.

Emotionality.

The mood of an individual; the amount and intensity of positive and negative emotions.

Empathy.

Feel with someone; emotional reaction similar to the emotion another person is perceived to experience; see sympathy.

Encoding.

Conversion of external stimulation to mental representations.

Enculturation.

Acquisition of a culture’s practices, customs, norms, values, and the like; the first foundation in this process is children’s innate social orientation.

Epigenesis.

Developmental process by which an individual’s genetic dispositions are modified by environmental influences and change the structure and behavior of the organism.

Episodic memory.

Memory of events in which an individual has participated, such as what he or she did during the summer holidays; see autobiographical memory, long-term memory, semantic memory and working memory.

Equifinality.

The principle that different conditions and developmental pathways can lead to the same end result.

Equilibration.

According to Piaget, a process that leads children to search for solutions to cognitive contradictions and to integrate established cognitive schemas and new experiences.

Ethology.

The study of human and animal behavior under natural conditions and of the role of behavior in evolution. Also a branch of evolution-based psychology.

Evolutionary psychology, Evolution-based psychology.

School of thought that focuses on the function of a particular behavior pattern during evolution, in the context of explaining human actions.

Executive functions.

Cognitive functions that monitor and regulate attention and plan and supervise the execution of voluntary actions, including the inhibition to act on inappropriate impulses.

Exercise play.

Non-functional practice in performing different actions; see constructive play, group play, rule-based play and symbolic play.

Exon.

Active base in a DNA sequence that encodes proteins and other cell products; see intron.

Exosystem.

Subsystem of Bronfenbrenner’s bio-ecological model consisting of broader social contexts that do not include the child itself, but that are important to the functioning of family and child, such as the parents’ workplace and social networks, distant relatives and parents of friends; see ecological psychology, macrosystem, mesosystem and microsystem.

Expansion (in language development).

The repetition of what a child is saying by an adult, with longer sentences and greater complexity.

Experiment.

Method to test a hypothesis on specific causal relationships or connections. One or several conditions are systematically altered, and the effect is recorded. As many conditions as possible are kept constant in order not to affect the outcome, increasing the probability that the results are solely related to the conditions being studied.

Exploration.

According to Bowlby, a behavioral system whose function is to provide information about the environment and enable the individual to better adapt to it; activated by unfamiliar and/or complex objects; deactivated once the objects have been examined and become familiar to the individual; see attachment and secure base.

Exploratory behavior.

According to Bowlby, exploratory behavior consists of three elements: an orienting response, movement in the direction of the object, and physical exploration of the object by moving it and experimenting with it; see attachment.

Expressive language.

The language that the child produces; see receptive language.

Expressive style (in early language development).

According to Nelson, speech characterized by a social expressions; see referential style.

Extension (of a concept).

All actual and possible exemplars encompassed by a concept; see intension (of a concept).

Externalizing disorder.

Negative emotions directed at others; often expressed in the form of antisocial and aggressive behavior.

Extinction (in conditioning).

Reduction or discontinuation of a conditioned response.

Extraversion.

One of the big five personality traits; the opposite of introversion; see agreeableness, conscientiousness, neuroticism and openness to experience.

F

False belief tasks.

Tasks where the child must infer a false belief in another person; used to investigate theory of mind in children; see mind understanding.

Family study.

Study based on the percentage of genes shared among family members; used to study the relationship between heredity and environment.

Feature-based category.

Conceptual category whose members share a set of common characteristics that distinguishes the category from other conceptual categories; see prototype category.

Fetal alcohol syndrome (FAS).

Abnormal development caused by the mother’s consumption of alcohol or other drugs during pregnancy; common characteristics include a small head, distinctive facial features, malformations of the heart and limbs, irritability, attention deficit disorder and hyperactivity.

Fetal period.

Ninth week of pregnancy until birth; see embryonic period and germinal period.

Field experiment.

Experimental method based on modifying independent variables in an individual’s natural environment.

Figurative language.

Language that makes use of metaphors or similes to express facts or ideas; see metaphor.

Fine motor skills.

Movements of the hands, fingers and toes; see gross motor skills.

First-order belief attribution, first-order theory of mind.

The ability to understand what another person is thinking; see second-order belief attribution.

Fixed action pattern.

Behavior shared in almost identical form among most members of a species (may vary between male and female); triggered by specific types of stimulation, but more complex than reflexes.

Fluid intelligence.

Basic skills such as memory and spatial perception whose development is relatively independent of specific cultural experiences; see crystallized intelligence.

Flynn effect.

Increase in skills and knowledge that over time leads to changes in the norms of IQ tests.

Form constancy.

The ability to recognize an object from different visual angles; see color constancy and size constancy.

Formal operational stage.

According to Piaget, the fourth and final stage in cognitive development, starting around the age of 11; see concrete operational stage, preoperational stage and sensorimotor stage.

Formal operational thinking.

According to Piaget, the highest form of cognitive functioning, where thinking is completely free of specific objects and experiences.

Fortuitous realism.

According to Luquet, the first of four stages in the development of drawing skills; see failed realism, intellectual realism and visual realism.

Fragile X syndrome.

Hereditary condition that mainly affects boys; caused by damage to the X chromosome. Characterized by the development of an elongated head, a large forehead, a high palate and a prominent chin following puberty. Often, but not always, entails learning disabilities of widely varying degree, from mild to severe, and occasionally autism.

Functional equivalence.

Refers to the fact that characteristics, behavior patterns or stimulation fulfill the same function in different individuals (for example in different cultures), or in the same individual at different age levels.

Functional magnetic resonance imaging (fMRI).

Method to examine the brain by measuring the oxygen content or changes in oxygen content in different brain areas while the subject performs a specific task, such as looking at something, listening to something or performing mental calculations.

Functional play.

See exercise play.

G

Gender constancy.

The ability to understand that an individual’s gender is linked to certain biological characteristics and remains the same, regardless of clothing and the like.

Gender difference, Sex difference.

Characteristic, ability or behavior pattern that differs between the two sexes.

Gender identity.

Sense of belonging to a particular gender; according to Kohlberg, the ability to distinguish between male and female.

Gender role, Sex role.

Expectations about the actions or behavior of boys, girls, men and women in a particular society under different circumstances.

Gender stereotype.

Generalized and often erroneous view of the behavior and characteristics of boys, girls, men and women.

Gender typing.

The process of adopting behavior and attitudes that a given culture regards as appropriate for males and females.

General factor, g-factor (in intelligence).

Domain-general ability; see specific factor.

Generalize.

To perceive and react in the same way to events that are similar in some respects; see discriminate.

Genital phase.

According to psychoanalytic theory, the mature stage of psychosexual development, beginning with puberty; see anal phase, latency phase, oral phase and phallic phase.

Genome.

The sum of all genes of an individual.

Genomic imprinting.

Activation of a gene depending on whether the gene is inherited from the father or the mother; see dominant gene and recessive gene.

Genotype.

The genetic makeup of an individual; see phenotype.

Germinal period.

The first ten days of prenatal development; see embryonic period and fetal period.

Gestalt principles (in perception).

Principles used for perceptual organization and presumed to be innate.

Gesture.

Distinct movement primarily used as a means of communication and interpreted consistently within a social system; see deictic gesture and symbolic gesture.

Giftedness (intelligence).

Scores in the high end of the IQ distribution, above 130.

Goodness of fit.

A measure of how well something fits together with something else; often used to describe the degree to which the temperaments of parents and children coincide.

Grammar.

Rules that describes how sentences are formed in a language; includes morphology and syntax.

Gross motor skills.

Movements of the body, arms and legs; see fine motor skills.

Group play.

Play in which several children interact; see associated group play, collaborative play, constructive play, exercise play, rule-based play and symbolic play.

Growth spurt.

Rapid growth in body height during early puberty; also used to describe the rapid growth of a characteristic or function within a specific time period.

H

Habilitation.

The effort to improve and support functionality, interaction and quality of life for people with congenital or early-acquired disabilities; see rehabilitation.

Habituation.

Gradual reduction in the intensity of a reaction or response following repeated stimulation; allows an individual to ignore familiar objects and direct attention at new ones.

Head Start.

American preschool program during the 1960s and 1970s with the aim of providing support for children from low-income and socially disadvantaged families.

Heritability estimate.

Calculation of heritability based on the difference between the correlations of fraternal and identical twins.

Heterotypic continuity.

Refers to the fact that actions differ while function remains the same at different age levels; see continuity, discontinuity and homotypic continuity.

Hierarchical structure (of concepts).

Organization of objects or concepts into categories and subcategories that are part of larger categories.

Holophrase.

Single-word utterance that in early language development functions as an entire sentence; see over-extension and under-extension.

Homotypic continuity.

Refers to behavior that fulfills the same function at different age levels; see continuity, discontinuity and heterotypic continuity.

Horizontal décalage.

According to Piaget, the difference in the development of skills within a certain stage; see vertical décalage.

Horizontal relation.

Relationship in which both parties share an equal amount of knowledge and social power; see vertical relation.

Horizontal structure (in language).

Utterances consisting of several words that all lie within the same intonation contour; see intonation and vertical structure.

Hospitalization syndrome.

Bad health and delayed development in children due to being raised in poor institutional environments.

Hostile aggression.

Actions whose main objective is to harm someone else, such as when a child bullies another; see instrumental aggression, open aggression and relational aggression.

Huntington disease.

A heritable and as yet incurable neurodegenerative disease, characterized by involuntary jerking movements especially in the face, tongue, neck, shoulders, arms and legs; irritability, depression and dementia; usual onset between the ages of 30 and 40. Caused by a dominant gene located on chromosome 4.

Hydrocephalus.

Abnormal accumulation of fluid in the cavities or exterior part of the brain; can lead to enlargement of the head, brain atrophy, reduced cognitive abilities and epilepsy.

Hyperactivity.

Unusually high activity level that is difficult for an individual to control.

Hyperlexia.

Mechanical reading ability without understanding.

Hypertonia.

Increased tension, such as in the muscles; see hypotonia.

Hypoactivity.

Unusually low activity level; difficulties taking initiative.

Hypothetico-deductive reasoning.

Method of solving problems or seeking knowledge that proceeds from a general assumption about the relationship between different factors and develops hypotheses that can be tested systematically; see deductive reasoning and inductive reasoning.

Hypotonia.

Reduced tension, such as in the muscles; see hypertonia

I

Id.

In psychoanalytic theory, one of the three parts of the human psyche, consisting of drives that seek to find an outlet; see ego and superego.

Identification.

Process characterized by a tendency to mimic behavior and assume someone else’s points of view.

Identity.

An individual’s sense of who he or she is, as well as of affiliation with larger and smaller social groups and communities.

Imitation.

The deliberate execution of an action to create a correspondence between what oneself does and what someone else does; see delayed imitation, immediate imitation and modeling.

Immediate imitation.

Deliberate repetition of another person’s action immediately after it has been performed; see deferred imitation.

Imperative communication.

See instrumental communication.

Implicit reasoning.

Automatic and nonconscious inferences based on knowledge and experience; see explicit reasoning.

Imprinting.

A form of rapid learning that takes place during a short and sensitive period immediately after birth; ducklings, for example, will follow the first person, animal or object they see move within a period of 48 hours after hatching.

Incidence.

The appearance of new occurrences of a trait, disease or similar in a particular population during a particular time span, often expressed as the number of incidences per 1 000 individuals per year; see prevalence.

Independent variable.

A condition that varies naturally or is deliberately varied to investigate its effect on what is being measured; see dependent variable.

Individual differences.

Variation in skills and characteristics between the individuals in a population; see atypical development and typical development.

Individualistic society.

Emphasis on the uniqueness of each individual; see collectivistic society.

Induced memory.

Memory of an experienced event that is “planted” in a person without the latter actually having experienced the event.

Inductive reasoning.

The establishment of a general rule based on specific experience; see deductive reasoning and hypothetico-deductive reasoning.

Infancy.

The first year of life.

Information processing (theory).

Psychological theories based on the assumption that all mental phenomena can be described and explained by models in which the flow of information is processed by one or more systems.

Inhibition.

Shyness and withdrawal from social challenges.

Instinct.

Species-specific behavior with a genetic basis, such as nest-building among birds.

Instrumental aggression.

The use of aggressive actions to achieve a goal, such as when one child pushes another off a bike in order to ride the bike themselves; see hostile aggression, open aggression and relational aggression.

Instrumental communication.

Communicative action aimed at getting someone else to do something specific; see declarative communication.

Integration (in development).

Coordination; progress toward greater organization and a more complex structure.

Intellectual disability, Learning disability, Mental retardation.

Significant problems learning and adjusting that affect most areas of functioning; graded mild (IQ 70–50), moderate (IQ 49–35), severe (IQ 34–20) and profound (IQ below 20); in clinical contexts, a significant reduction in social adjustment is an additional criterion.

Intelligence quotient (IQ).

Numerical representation of an individual’s intelligence in relation to peers. Formerly, IQ was based on the relationship between mental age and chronological age, calculated by dividing the age score on an IQ test by the individual’s chronological age; today, IQ tests are based on a standard score with a mean of 100 and a standard deviation of 15 or 16, depending on the test being used.

Intension (of a concept).

The content, all of the attributes embraced by a concept; see extension.

Intentionality.

Goal-oriented determination; includes a notion of ​​the goal of an action, and emotions and plans related to achieving the goal.

Inter-observer reliability.

The degree of concurrence in the scoring or assessment by two or more persons who observe the same event independent of each other, directly or on video.

Inter-sensory perception.

The influence of one sensory modality on the processes of another.

Interaction (statistics).

The degree of influence of one or several other variables on the relationship between an independent and a dependent variable; see moderator.

Interaction effect.

An influence by one or several other factors; see main effect and transaction effect.

Intermodal perception.

Perception of a person, an event or an object whereby information from two or more senses is combined, for example seeing and hearing a cat meow.

Internalization.

Process whereby external processes are reconstructed to become internal processes, such as when children independently adopt problem-solving strategies they have previously used in interaction with others, or adopt the attitudes, characteristics and standards of others as their own.

Internalizing disorder.

Negative emotions directed at oneself, anxiety, depression; often involving a negative self-image, shyness and seclusion; see externalizing disorder.

Interpretative mind.

Describes the fact that two people can perceive the same information differently; see mind understanding.

Intersubjectivity.

The consciously shared subjective experience of an event or phenomenon by two or more individuals simultaneously.

Intonation.

The melody or pattern of changes in the pitch of the speaking voice.

Intron.

Inactive base of a gene in a DNA sequence; see exon.

Introversion.

Personality trait characterized by shyness, anxiousness and withdrawal from social situations, as opposed to extraversion.

Irritability (temperament).

Tendency of an individual to become easily agitated and lack patience and tolerance.

J

Joint attention.

Two or more individuals share a common focus of attention, while at the same time being aware that the same focus of attention is shared by the other person(s).

K

Klinefelter syndrome.

Chromosomal disorder caused by an additional X chromosome in males (XXY); symptoms include sterility, small testes, and long arms and legs; see sex chromosomes.

L

Landmark.

Distinctive spatial feature used to orient oneself in one’s surroundings, such as the color of the walls or the placement of windows, doors and objects.

Language Acquisition Device, LAD.

According to Chomsky, an innate grammatical representation, a module for language that underlies all languages and enables children to learn to understand the language around them and assemble words into grammatically correct phrases.

Language Acquisition Support System, LASS.

According to Bruner, the systematic way in which the environment supports a child’s language development; see scaffold.

Language function.

The purpose of speech; the objective one wants to achieve by conveying something to another person using language.

Latency phase.

According to psychoanalytic theory, a period of reduced sexual drive without focus on a new area of the body; lasts from the end of the phallic phase until puberty (approx. age 6–13); see anal phase, genital phase, oral phase and phallic phase.

Laterality.

Asymmetry in the functioning of the brain, when some functions are more prominent in one brain hemisphere than in the other.

Learned helplessness.

The experience of lacking self-determination and the ability to affect one’s environment as a result of having experienced situations in which one felt little control.

Learning.

Relatively permanent change in understanding and behavior as the result of experience; see development and maturation.

Learning disorder.

Significant problems developing skills in a specific area of knowledge, such as language impairment, reading/writing disorders (dyslexia) and difficulties with math (dyscalculia); often referred to as specific learning disorder as opposed to general learning disability; see intellectual disability.

Learning Potential Assessment Device.

Test procedure to assess a child’s learning abilities; tests are first performed in the traditional way, after which the child receives specific and standardized help with the tasks the child was unable to solve independently; an increase in the test score following instruction is considered a measure of the child’s learning potential; see dynamic assessment.

Lexical development.

The development of vocabulary.

Libido.

Sexual or life drive; according to psychoanalytic theory, a source of energy aimed at reproduction, but among human beings also converted into other forms of expression. Motivates all action together with Thanatos.

Logical constructivism.

Psychological tradition that includes Piaget’s theory and the theories of others that build on it; its main principle is that children actively construct their own understanding of the outside world, and that perception and cognition are affected by logical and conceptually driven processes; see constructivism and social constructivism.

Logical reasoning.

Reasoning whose deductions are limited by the rules of logic.

Long-term memory.

Part of the memory system that stores memories over time and contains most of an individual’s knowledge; see autobiographical memory, episodic memory, semantic memory and working memory.

Longitudinal study.

Research method that involves the observation of the same individuals at various age levels; see cross-sectional study.

M

Macrosystem.

Subsystem of Bronfenbrenner’s bio-ecological model; includes social institutions such as government, public services, laws, customs and values ​​of importance to what takes place in the other systems; see exosystem, mesosystem and microsystem.

Magnetic resonance imaging, MRI.

Method of studying the brain that yields black-and-white images of the brain’s shape and size. MRI is sensitive to the cell differences in various tissue types, such as white and gray brain matter.

Main effect.

An influence that is independent of other factors; see interaction effect and transaction effect.

Maladaptation.

Mental disorder or anti-social behavior with a basis in an individual’s lack of adaptability and difficulties adjusting to the environment.

Maturation.

Developmental change caused by genetically determined regulating mechanisms that are relatively independent of the individual’s specific experiences; see development and learning.

Mean length of utterance (MLU).

Average number of morphemes per utterance; generally calculated on the basis of 100 utterances, and used to measure a child’s level of language proficiency.

Mediator.

Active factor in the impact of an independent variable on a dependent variable.

Memory span.

The amount of information an individual is able to keep in working memory, such as the number of digits a child can recall after seeing or hearing them once.

Mental age.

See age score.

Mental disorder. 

Behavioral or psychological pattern that occurs in an individual and leads to clinically significant distress or impairment in one or more important areas of functioning.

Mental model.

Subjective mind model of how the world functions and how things are connected.

Mentalizing.

The interpretation of one’s own and others’ behavior as an expression of mental states, desires, feelings, perceptions, etc.; according to Fonagy, a process that includes all thoughts about relationships, human interactions and psychological processes in humans.

Mesosystem.

Subsystem of Bronfenbrenner’s bio-ecological model; consists of connections between two or more microsystems a child actively participates in; see exosystem, macrosystem and microsystem.

Meta-knowledge.

Knowledge about knowledge, for example metalinguistic insight into language itself.

Metaphor.

A type of analogy; meaning expressed illustratively or figuratively.

Microgenetic study.

A study in which the development of a skill is mapped from the moment a change takes place until the child masters the skill.

Microsystem.

Subsystem of Bronfenbrenner's bio-ecological model that includes the child’s closest daily relationships, usually the parents, siblings and other relatives living with the family, preschool, school, youth clubs, neighborhood friends and the like; see mesosystem, exosystem and macrosystem.

Mind understanding.

Understanding that other people have internal states, such as knowledge, feelings and plans, that may be different from one’s own and may affect their actions; see social cognition and theory of mind.

Mind-oriented.

Relating to other people as cognitive individuals.

Minority language.

Language ​​spoken by a minority of a society’s population.

Mirror neuron.

Nerve cell that is activated both when an individual observes an action and when he or she performs the action.

Modeling.

Type of observational learning, whereby an individual learns by observing and imitating other people’s behavior and its consequences; see imitation.

Moderator.

Variable that affects the strength of the relationship between two other variables; see interaction.

Module (in cognition).

Isolated brain system that deals with a particular type of stimulation and knowledge.

Monozygotic twins, Identical twins.

Twins resulting from the splitting of the same fertilized egg, sharing 100 percent of each other’s genes; see dizygotic twins (fraternal twins).

Moral dilemma.

Situation involving a conflict between two or more solutions that may violate an individual’s perception of what is right and wrong.

Moral realism.

According to Piaget, the second of three stages in moral development, beginning at five years of age; characterized by the child’s ability to follow rules, but in an absolute way, i.e. with little ability to adapt or change the rules; see moral subjectivism and premoral stage.

Moral reasoning.

Reasoning about real or hypothetical moral dilemmas.

Moral subjectivism.

According to Piaget, the third and final stage in moral development; begins at age 9–10; characterized by the child’s understanding that rules are conventional, social constructions based on consensus, and that it is possible to change them if consensus can be reached; see moral realism and premoral stage.

Moro reflex.

Developmental reflex elicited when an infant extends her arms and the head suddenly loses support, causing the infant’s arms to move toward the body’s midline; usually disappears at 5–6 months of age.

Morpheme.

Smallest grammatical unit in a language that changes the meaning of a word; can be a word or part of a word, such as the conjugation of a verb.

Morphism.

In Piaget’s new theory, correspondence beyond identical resemblance.

Morphology.

The study of how words are built up; includes the creation of content words like ball and run, functional words like and and in, andinflections of word forms like run, ran and running.

Multilingualism.

Proficiency in two or more languages at roughly the same level, with bilingualism being the most common form. Multilingualism may be practiced within the family alone, or between the family and society; see minority language.

Multiple intelligences.

According to Gardner, different forms of intelligence among human beings.

Mutation.

Sudden change in a gene.

Myelination.

The formation of a thin myelin sheath around the nerve fibers, consisting of proteins and fat and leading to an increase in the transmission of nerve impulses.

N

Nativism.

Theoretical assumption that development proceeds according to a plan that in some way is represented genetically, and that experience has little or no effect on the developmental outcome; see maturation.

Natural selection.

The principle that genetic changes in a species are due to the fact that offspring with characteristics well-adapted to the current environment are most likely to grow up and propagate, and thus pass on those properties to later generations.

Naturalistic observation.

Research method involving the observation of an individual’s regular activities in his or her ordinary environment without any attempt at outside influence.

Negative reinforcement (in conditioning).

A stimulation or event that, when removed from a situation, increases the probability of an individual performing a specific action; for example, the likelihood of a child doing homework may increase when this results in eliminating the threat of having to stay after school; see positive reinforcement and reinforcement.

Neglected children (sociometry).

Children who are neither accepted nor rejected by their peers; few features distinguish them from other children, but they have less interaction with others, and little attention is paid to them; they typically show little aggressiveness and seem to try to avoid aggression to a somewhat greater degree than other children, but do not appear overly anxious or withdrawn; see controversial children, neutral children, popular children and unpopular children.

Neonatal period.

The first month of life.

Neuroimaging.

Using technology to create images of the structures and functions of the brain. 

Neuronal group theory.

Theory of motor development based on the assumption that evolution has resulted in a structure of primary neuronal groups (nerve cell connections) that controls motor functions and changes with experience, i.e. that information from the muscles affects the development of the brain.

Neuroticism.

One of the big five personality traits; see agreeableness, conscientiousness, extraversion and openness to experience.

Neurotransmitter.

Chemical substance released from an axon to a neuron that affects the activity of another neuron.

Neutral children (sociometry).

Children who do not fall into a particular group when their popularity is evaluated by their peers, i.e. who are neither popular, unpopular or controversial, but who at the same time are not neglected children.

New theory.

See The new theory.

Norm (in a test).

A standard or normative score for a certain age level, based on the results from a large number of individuals.

Norm-referenced test.

Test that is standardized based on a representative group and scaled in such a way that the score reflects an individual’s performance relative to the performance of the standardized group; see criterion-referenced test.

Normal distribution.

Statistically defined distribution around a mean; also called Gaussian curve.

Normal expectable environment.

Natural variation in environmental conditions associated with the normal development of children born without particular biological abnormalities.

O

Object (in psychodynamic theory).

Mental representation of a person or an object that is the goal of a drive, or through which a drive can achieve its goal; see object relation.

Object constancy.

Understanding that an object remains the same despite changes in how it appears in different light, perspective or distance.

Object permanence.

Understanding that an object continues to exist even though it cannot be perceived by the senses.

Object relation.

In psychodynamic theory, the dynamic interaction between an individual’s mental representations of him or herself, and emotionally significant persons in the environment.

Observational learning.

Learning by observing the behavior of others and the consequences of their behavior.

Oedipus conflict.

According to psychoanalytic theory, a genetically determined psychological conflict rooted in the idea that boys are sexually attracted to their mother and experience the father as a competitor for the mother’s affection; equivalent to the Electra conflict in girls.

Ontogenesis.

The developmental history of an individual.

Open aggression.

A form of hostile aggression; actions whose purpose is to harm another person physically; see hostile aggression, instrumental aggression and relational aggression

Openness to experience.

One of the big five personality traits; see agreeableness, conscientiousness, extraversion and neuroticism.

Operant conditioning.

See conditioning.

Operation (cognitive).

According to Piaget, the mental representation of actions that follow logical rules.

Operationalization (in research).

Normative definition or precise description of how to measure what is being studied.

Oppositional defiant disorder.

Externalizing disorder characterized by hostility toward adults, reluctance to do what authorities say and to follow normal rules, and maliciousness and vindictiveness when met with resistance.

Oral phase.

According to psychoanalytic theory, the first stage in psychosexual development, in which the area around the mouth becomes a source of pleasure; age 0–1 years; see anal phase, genital phase, latency phase and phallic phase.

Orienting response.

Directing one’s attention at a new stimulus.

Orthogenetic principle.

The principle that all development involves changes in a positive direction: greater differentiation, integration, organization, etc.

Over-controlled behavior.

Inhibited and anxious behavior; see under-controlled behavior.

Over-extension.

Use of a word beyond its usual meaning; see under-extension.

Over-regulation (in language development).

Application of a general grammatical rule beyond the particular cases it applies to, for example goed instead of went.

Over-stimulation.

More stimulation than an organism is able to deal with at its current level; see under-stimulation.

P

Painter’s cues (depth perception).

Information about light, surface, height and similar used as indicators of the position of objects relative to each other, for example the fact that one object can cover another object located further back in the room, and that objects that are further away are positioned “above” objects that are closer; see depth perception and stereoscopic vision.

Palmar grasp reflex.

Developmental reflex causing the fingers to flex inward when the infant’s palm is gently touched; usually disappears at 2–4 months of age.

Parallax movement.

Apparent motion of an object located at a short distance, when first looking with one eye only, followed by the other. Also discernable when the head is moved to the side: close objects are shifted to one side of the visual field, and objects further away to the other.

Parallel play.

Play in which several children play side by side with similar objects or in a similar way, but without interacting.

Parenting style.

General description of how parents raise their children; see authoritarian, authoritative, disengaged and permissive parenting style.

Perception.

Knowledge gained through the senses; discernment, selection and processing of sensory input.

Perceptual constancy.

Awareness of perceptual characteristics as constant, even though the lighting conditions and the image projected on the retina may vary.

Perceptual preference.

Method to examine how a child perceives the surroundings; involves measuring what the child is attentive to for the longest amount of time; see preference method.

Perinatal.

Period just before and after the of birth.

Permissive parenting.

Parenting style that places few demands on the child, but in which parents are responsive; see authoritarian, authoritative and disengaged parenting style.

Personal narrative.

See autobiographical memory.

Personality.

An individual’s characteristic tendency to feel, think and act in specific ways.

Personality traits.

Summary description of an individual’s personality.

Phallic phase.

According to psychoanalytic theory, the third phase in psychosexual development, in which the genital area becomes a source of pleasure; age 4–5 years; see anal phase, genital phase, latency phase and oral phase.

Phenotype.

An individual’s observable physical and psychological characteristics; see genotype.

Phenylketonuria (PKU).

Hereditary disorder in the production of the enzyme phenylalanine hydroxylase, leading to elevated levels of phenylalanine in the blood; causes severe mental and physical impairment if left untreated by a dietary regimen.

Phoneme.

The smallest unit of sound that distinguishes two words in a language; /m/ and /p/, for example, are different phonemes in English, since mile and pile are different English words; see morpheme.

Phonology.

Branch of linguistics dealing with the sounds of spoken language.

Phylogenesis.

The evolutionary historyof a species or an attribute.

Physical causality, understanding of.

Understanding of how physical objects behave and interact with one another; see causality and psychological causality.

Pincer grip.

Grip of the thumb and index finger.

Plantar reflex.

Developmental reflex that causes the toes to flex inward when the ball of the foot is stimulated; usually disappears at 9–10 months of age.

Plasticity (in development).

The ability of an organism to change and adapt in response to experiences; frequently used in connection with the nervous system; see constraint.

Pleasure principle.

According to psychoanalytic theory, one of two principles governing human functioning; seeking the immediate satisfaction of drives, needs and desires regardless of consequences; see reality principle.

Polygenic inheritance.

Refers to the interaction of several genes in shaping a characteristic that varies among the population.

Popular children (sociometry).

Children who are actively accepted by other children. Often they are physically strong with an attractive appearance, but their willingness to share, ability to cooperate and other social skills are equally important for their acceptance and popularity among peers; see controversial children, neglected children, neutral children and unpopular children.

Population (in statistics).

The sum total of individuals, objects, events and the like included in a study. Also used to describe a group of individuals with a common measurable attribute, such as children in a certain school grade or young people in cities.

Positive reinforcement (in conditioning).

An event or other factor that, when injected into a situation, increases the likelihood of a particular action; for example, the likelihood of a child doing homework may increase when homework leads to good grades; see negative reinforcement and reinforcement.

Post-conventional morality.

According to Kohlberg, the third and final of three main stages of moral development; characterized by abstract values that are valid under all circumstances and in every society; see conventional morality and pre-conventional morality.

Postnatal.

After birth.

Prader-Willi syndrome.

Genetic syndrome characterized by short stature, hypotonia, an insatiable appetite and often mild learning disabilities; caused by a missing or unexpressed part of chromosome pair 15, inherited from the father; the counterpart to Angelman syndrome; see genetic imprinting.

Pragmatic reasoning.

Reasoning based on schemas abstracted from one’s own past experiences in similar situations.

Pragmatics (in language).

Functions of language in everyday use; see semantics.

Pre-conventional morality.

According to Kohlberg, the first of three main stages of moral development; characterized by moral reasoning based on reward, punishment and authority; see conventional morality and post-conventional morality.

Preference for novelty.

Tendency to be more attentive to new rather than familiar stimulation; appears in infants after the age of three months.

Preference method.

Method of measuring the proportion of time a child is attentive to each of two different stimuli, such as a simple checkerboard and a more complex visual pattern, or the mother’s voice and the voice of a stranger; children are said to show a preference for the stimulus they are attentive to for more than half the time.

Pre-linguistic.

Refers to children’s skills and abilities before they begin to speak, for example pre-linguistic communication.

Premoral stage.

According to Piaget, the first of three stages in moral development; lasts until 4–5 years of age; during this stage, children show a poor understanding of general rules and follow their own personal rules without a consistent system, based on their own wishes and needs; see moral realism and moral subjectivism.

Prenatal period.

The developmental period before birth.

Preoperational stage.

According to Piaget, the second of four stages in cognitive development, approx. age 4–7; see concrete operational stage, formal operational stage and sensorimotor stage.

Preschool age.

Age 3–6 years.

Pretend play.

Form of symbolic play that involves make-believe actions.

Primary emotions.

See basic emotions.

Primary intersubjectivity.

According to Trevarthen, younger infants’ perception of how they affect others, and the fact that others are aware of them; see secondary intersubjectivity.

Private speech.

Speech that does not convey enough information to allow the listener to understand what is being communicated.

Procedural memory.

Memory of how something is done; includes among other things the ability to form habits, acquire skills, and some forms of classical conditioning.

Prosocial behavior.

Behavior intended to help others and share objects or other benefits without advantage to the individual itself; see antisocial behavior.

Prosody.

The patterns of stress and intonation in a spoken language.

Prospective study.

Study that follows an individual over time; see retrospective study.

Protection (in development).

Conditions that reduce the negative effects of vulnerability and risk.

Prototype.

Typical exemplar of a concept.

Prototype category.

Conceptual category derived from a prototypical exemplar; see feature-based category.

Psychoanalytic psychology.

Psychological theories based on Freud’s theory and psychotherapeutic method (psychoanalysis); founded on the principle that an individual’s thoughts and actions are determined by drives and impulses and their internal, often unconscious, regulation through interaction between the different parts of the human psyche; both personality and mental problems of children and adults are explained on the basis of unconscious processes and conflicts rooted in early childhood; see ego, id, psychodynamic theory and superego.

Psychodynamic psychology.

Tradition that emphasizes the importance of feelings and needs for an individual’s thoughts and actions; describes personality and its development based on the assumption that the human psyche involves mental forces that frequently are in conflict with each other, and have an important basis in early childhood; psychoanalysis belongs to this tradition.

Psychological causality, understanding of.

Understanding of the intent or motivation behind an action; see causality.

Psychometrics.

Measurement of individual differences in psychological characteristics.

Psychosexual phase.

According to psychoanalytic theory, a critical period in which a child’s mental energy is directed toward a specific area of the body; the development of an individual’s personality and sociocultural adaptation depends on certain stimuli and experiences and the resolution of mental conflicts during these periods; see anal phase, genital phase, latency phase, oral phase and phallic phase.

Psychosocial crisis.

According to Erikson, a critical period of developmental challenges or tasks related to the formation of specific characteristics; the experience of a psychosocial crisis leaves a permanent mark on an individual’s personal and social development, and has consequences for the course of future psychosocial crises.

Psychosocial moratorium.

According to Erikson, a period in which adolescents have not yet decided on a future career or role in society, and find themselves between the safety of childhood and the independence of adult life (autonomy).

Psychopathology.

Mental problems and disorders that make every day functioning difficult.

Punishment.

In behavioral psychology, any event that reduces the probability of repeating an action under similar circumstances; see reinforcement.

Q

Qualitative change.

Change in the nature or quality of a phenomenon; see quantitative change.

Qualitative method.

Research method involving the use of descriptions and categories that need not be quantifiable, and analyses not based on measurements and numerical processing; does not require replicability, but the researcher must be able to account for his or her standpoint and the basis for interpreting what has been observed; see quantitative method.

Quantitative change.

Quantifiable change in the nature or quality of a phenomenon, measurable in degree, amount, number, and the like; see qualitative change.

Quantitative method.

Research method involving the use of quantifiable descriptions and categories, and analyses based on measurements and statistical processing; requires replicability; see qualitative method.

R

Raw score (in testing).

The total number of points scored on a test; see standard score.

Reaction range.

The degree to which a developmental process can be influenced at a particular point during development.

Reaction to novelty.

Behavior characterized by shyness and uncertain reactions to new situations, objects and people.

Reality principle.

According to psychoanalytic theory, one of two principles that govern human functioning; seeking to satisfy drives, needs and desires in relation to what is realistic, i.e. what is possible within a given physical, social and cultural environment; see pleasure principle.

Recall.

Recollection of an experience without perceptual support; see recognition.

Receptive language.

The language that the child understands; see expressive language.

Recessive gene.

Gene that is only expressed when present on both chromosomes of a pair, one from each parent; see dominant gene and genetic imprinting.

Recognition.

The process of experiencing something in the moment that has been experienced before, such as when children consciously or nonconsciously show that they have seen a particular image before; see recall.

Reductionism.

Theoretical model that attempts to explain phenomena at a higher systemic level based on processes and elements at a lower systemic level, such as explaining complex traits and skills based on the notion that they arise from a set of simpler traits and skills.

Reference group.

Group that forms the basis for an individual’s values, norms, attitudes and behaviors.

Referential communication.

Use of language that enables the other person to identify a particular individual, object or event in the current environment.

Referential style (in early language development).

According to Nelson, speech characterized by a preponderance of words referring to objects; see expressive style.

Reflective abstraction.

According to Piaget, knowledge acquired by thinking about one’s own thoughts and forming abstractions based on these personal reflections; see cognitive structure.

Reflex.

Unlearned and involuntary response to an external stimulus.

Refreshment (of memory).

Repeated presentation of an object or event previously experienced by an individual.

Regression.

The relapse into earlier, more primitive or childish ways of functioning.

Regulating function of language.

Use of language to regulate one’s own behavior.

Rehabilitation.

The effort to build up new or previously existing functions and restore opportunities for interaction and quality of life for people with acquired disabilities; see habilitation.

Reinforcement (in conditioning).

In classical conditioning: presentation of an unconditioned stimulus and a neutral stimulus that becomes a conditioned stimulus, such that the conditioned response is triggered more consistently. In operant conditioning: events that follow the execution of an action and increase the likelihood of repeating the action under similar circumstances.

Relational aggression.

A form of hostile aggression; actions whose main intent is to damage the relationship between two people, for example by speaking ill of them; see hostile aggression, instrumental aggression and open aggression.

Relational emotion.

Emotion exclusively directed at other people, such as love, hatred or jealousy; see basic emotions and self-conscious emotions.

Reliability.

Measure of how dependable a piece of information is, and whether the observational categories and measuring methods lead to the same result after repeated observation; see validity.

Replicability (in research).

Requirement that another person has to be able to perform a study in precisely the same way it was originally carried out, and arrive at approximately the same result.

Representation (mental).

An individual’s mental storage of understanding and knowledge about the world.

Representative sample.

A group of individuals with the same distribution of relevant characteristics as the population represented by the sample, so that the results of the sample can be assumed to be valid for the entire population.

Research design.

Plan for how and when to collect scientific data in a study.

Resilience.

Attributes that lead to a positive development under difficult childhood conditions, such as children who are biologically or socially at risk of aberrant or delayed development; see vulnerability.

Responsivity (as a human trait).

The ability to provide a quick and appropriate response to an individual’s signals and behavior; see sensitivity.

Responsivity (as a characteristic of play objects).

Measure of the extent to which objects “react” when children play with them, for example whether they move, emit a sound or change shape.

Retrospective study.

Study in which an individual is asked about earlier events.

Rett syndrome.

Genetic syndrome that almost exclusively affects girls; characterized by severe intellectual disability and motor and language impairment; development is often normal for the first 6–18 months of life, with a consequent decline in functioning. Believed to be mainly caused by a defective control gene (MECP2) on the X chromosome that fails to switch off other X chromosome genes at the right time; see genomic imprinting.

Reversibility (in cognition).

The understanding that a change in one direction can be counteracted by a change in the opposite direction, for example that a ball of clay shaped into a sausage can be reshaped into a ball.

Ribonucleic acid (RNA).

Macromolecular compounds carrying genetic information and responsible for cellular protein synthesis.

Rigidity.

Personality trait characterized by poor social adaptability and lack of flexibility.

Risk.

Increased likelihood of a negative developmental outcome; may be linked to biological and environmental factors.

Ritualization.

Process whereby involuntary forms of expression, such as facial expressions, evolve into signals; or a process whereby a voluntary action becomes a communicative gesture, for example when a reaching movement turns into a pointing gesture.

Role.

Expectations of certain action patterns and behaviors associated with an individual by virtue of their function or position in society, for example as a girl, teenager or boy scout.

Role-play.

Form of pretend play in which the participants make believe they are another person, an animal or a human-like figure.

Rooting reflex.

Developmental reflex elicited when an infant is lightly touched on the cheek and turns the head toward the side being stimulated; usually disappears at three months of age.

Rough-and-tumble play.

A type of exercise play in which children run after each other, push, tickle, play-fight and similar.

Rule-based play.

Play in which children must follow specific rules for what is allowed or not allowed, for example games such as tag, Ludo (Parcheesi), or hide and seek; see constructive play, exercise play, group play and symbolic play.

S

Scaffold.

In social constructivism, the external regulation, help and support provided by adults or more experienced peers to children, adapted to their level and allowing them to transcend their independent copingskills and develop new skills and knowledge; see zone of proximal development.

Schema.

Mental representation that emerges when actions are generalized by means of repetition and transformed through mental processing, thus shaping the individual’s perception of the environment; see cognitive structure.

School age.

Age 6–12.

Screening test.

Brief test that aims to identify individuals who should be examined using more thorough and time-consuming methods.

Script (cognition).

Generalized mental representation of a sequence of events that recur within the context of a specific situation; provides among other things the basis for an individual’s expectations of how to behave in different situations, such as at school or at a restaurant.

Second-order belief attribution, second-order theory of mind.

The belief of one person’s thoughts about another person’s thoughts, what A thinks B is thinking; see mind understanding, theory of mind.

Secondary intersubjectivity.

According to Trevarthen, the joint attention of children and adults on something outside themselves, as well as their awareness of each other’s attention.

Secure base.

Describes the function of caregivers when they give younger children the opportunity for controlled exploration of objects and environments that can elicit fear, and to seek refuge when they become apprehensive; see attachment.

Segregation (education).

Special educational alternative outside the ordinary preschool group or school class a child is part of; see desegregation.

Self.

Personal awareness, perception or evaluation of oneself.

Self as knower.

The I, the subject that perceives its own existence and presence in the world; see self as known.

Self as known.

The me, the entire complex of characteristics an individual thinks of when reflecting on their own person; see self as knower.

Self-concept.

Awareness of having specific and independent traits; see self as known.

Self-referential emotion, Self-conscious emotions, Secondary emotions.

Emotion associated with an individual’s self-evaluation in relation to a standard based on personal emotional experiences and information provided by others; includes pride, shame, embarrassment, guilt and envy; see basic emotions and relational emotions.

Self-disclosure.

Communicating personal information about oneself to others; typical in adolescence.

Self-efficacy.

The experience of acting and having control over one’s own life; belief in one’s own ability to deal with different situations and events.

Self-evaluation, Self-esteem.

The assessment of one’s own characteristics in relation to an inner standard that includes how and who one wishes to be; can also refer to questionnaires, surveys and the like about a person’s characteristics.

Self-image.

Positive or negative perception of oneself and one’s own characteristics.

Self-organization.

The emergence or establishment of new structures not driven by external factors.

Self-regulation.

The ability to monitor and adapt one’s own thoughts, feelings, reactions and actions in order to cope with the requirements, challenges and opportunities of the environment and be able to achieve one’s goals; also referred to as self-control.

Semantic memory.

Long-term memory of general facts and knowledge, such as the name of the United States capital; see autobiographical memory, episodic memory, long-term memory and working memory.

Semantics.

The branch of linguistics concerned with the meaning of words and phrases.

Sensitive period.

Limited period of time when an individual is particularly susceptible to specific forms of positive or negative stimulation and experience; if the stimulation or experience does not take place during the given time period, the individual will still be able to take advantage of, or be impaired by, similar types of stimulation or experience later in life, but to a lesser extent; see critical period.

Sensitivity (of a caregiver).

Ability to understand a child’s condition, respond quickly and adequately to the child’s signals and behavior, and provide challenges the child is able to master; see responsivity.

Sensorimotor stage.

According to Piaget, the first of four stages in cognitive development, lasting until the age of two; see concrete operational stage, formal operational stage and preoperational stage.

Sensory integration.

Simultaneous use of different types of perceptual information within the same modality or from two or more modalities, such as the visual and acoustic characteristics of a person speaking.

Sensory modality.

One of several specific senses, such as vision or hearing.

Separation distress.

Emotional reaction elicited when a child is separated from a caregiver; also known as separation anxiety.

Separation syndrome.

See Bowlby-Robertson syndrome.

Sex.

See gender.

Sex chromosomes.

Chromosomal pair that determines the sex of an individual and differs between males (XY) and females (XX).

Sex-linked inheritance.

Inherited characteristic related to the genes on the sex chromosomes.

Shaping (of behavior).

Step-by-step reinforcement of behavior in such a way that it gradually changes and increasingly resembles desired behavior; part of operant conditioning.

Sign language.

Visual-manual language, primarily using movements of the arms, hands and fingers, supported by body movements, mouth movements and facial gestures.

Signals (in early development).

Infant actions and expressions used by adults as an indication of the infant’s interests, preferences and general well-being.

Significance (in statistics).

Indication of the likelihood that a statistical difference or relationship is based on pure coincidence.

Size constancy.

Ability to perceive the size of an object as constant despite changes in the size of the image projected on the retina; see color constancy, constancy and form constancy.

Slow-to-warm-up (temperament).

According to Thomas and Chess, slow adaptation to new situations; includes irregularities in daily routines and a tendency to cry and feel restless, but with moderate reactions; may initially resemble difficult temperament, but mostly resembles easy temperament once the individual has warmed up.

Sociability (temperament).

Interest and enjoyment in being in the company of other people.

Social cognition.

Cognitive processes that form the basis for understanding one’s own and other people’s intentions, motives, emotions, thoughts and social relations.

Social construction.

Anything rooted in or created by means of social interaction.

Social constructivism.

Psychological theories based on the notion that children construct their understanding of the outside world through interaction and cooperation with other people, and that people in different cultures (including the subcultures of a society) can perceive one and the same phenomenon in different ways; see logical constructivism.

Social learning theory.

See cognitive behavior analysis.

Social mediation.

Social communication of or guidance toward knowledge.

Social referencing.

Using other people’s emotional reactions to evaluate uncertain situations; see emotion regulation.

Social selection.

Selectivity in choice of friends and social relations.

Socialization.

Term frequently used synonymous with enculturation.

Sociobiology.

Branch of biology built on the assumption that complex forms of social behavior, such as aggression and altruism, have a genetic basis and have been shaped by evolution due to their survival value.

Socioeconomic status (SES).

Assessment of an individual’s economic and social status in society; for children, usually based on information about the parents’ education and occupation.

Sociogram.

A graphic representation of an individual’s social network; see sociometry

Sociometry.

Method used to map the popularity and status of individuals in a group, based on the opinions of other group members, such as asking children whom they would most and least like to spend time with; can be graphically represented as a sociogram.

Specific factor, s-factor (in intelligence).

Domain-specific ability; see general factor.

Speech act, Language act.

Action performed via a linguistic utterance, such as a greeting, question, narration, promise or command.

Stability (in development).

Describes the constancy of an individual’s position in relation to peers with respect to a particular characteristic; the fact that individual differences in the execution of a skill are constant from one developmental stage to another.

Stage (in development).

Delimited period of time in which thoughts, feelings and behavior are organized in a way that is qualitatively different from the preceding or following periods.

Stage theory.

Theory based on the assumption that development proceeds in distinct and qualitatively different stages.

Standard deviation.

Measure of the spread of quantitative data; indicates the average degree of deviation in the score or numerical value ​​of a variable from the total average; see normal distribution and variance.

Standard score (in testing).

Score based on standard deviation; indicates the relative ranking of an individual’s performance on a test compared with the statistical average and the distribution of scores in the standardization sample; see raw score.

Standard theory.

See The standard theory.

Standardization (of tests).

Systematic survey of test items among a representative sample of the population targeted by the test; aims to estimate the distribution of scores among a given population.

Stanford-Binet Intelligence Scales.

IQ test for ages 2–23; the 5th revised English-language edition (SB5) was released in 2003.

Stanine scale.

STAndard NINE is a method of scaling test scores based on a division of the normal distribution curve into nine steps, with a mean of five and a standard deviation of two.

Stereoscopic vision.

Ability to perceive space as three-dimensional due to a small difference between the images that are projected on the retina when the eyes are directed at the same point (parallax); see depth perception and painter’s cues.

Stereotype.

General and often erroneous view of the characteristics of a group of individuals, for example gender stereotype.

Strange situation.

Standardized situation to assess the quality of attachment between an adult and a child aged 1–2 years; see attachment.

Stranger anxiety.

Fear of strangers common in children during the early attachment period; see attachment.

Successive one-word utterances.

Utterances during early language development that consist of several thematically related words, but articulated in such a way that the words do not lie within the same intonation contour, but have short pauses between them; see horizontal structure, intonation and vertical structure.

Superego.

In psychoanalytic theory, one of the three parts of the human psyche, consisting of internalized demands and expectations, primarily from parents, but also from other important persons in the child’s environment; its function is to ensure that an individual’s actions remain within the norms and values of culture; see id and ego.

Symbol.

Something that represents something other than itself, such as a sign, a word, an image or the like.

Symbolic gesture.

Gesture that specifies or names the thing or category it refers to; see deictic gesture.

Symbolic play.

Play in which children take on the role of a person or an animal, and connect objects with a function unlike the one they usually have, performing a make-believe activity; seeconstructive play, exercise play, group play and rule-based play.

Synapse.

Contact point between the axon of a nerve cell and the body of another nerve cell via its dendrites; this is where the transmission of impulses occurs.

Synaptic pruning.

Selective loss of synapses during the first years of life due to lack of use.

Syndrome.

Set of attributes and behavioral characteristics that regularly occur together.

Syntax.

The grammatical arrangement of words and phrases in a language.

T

Tabula rasa.

“Blank slate”; common expression based on the assumption that humans are born with an empty mind that acquires content and structure through experience.

Telegraphic speech.

Incomplete utterances of only a few words during early language development; consists primarily of content words without functional words such as articles and prepositions.

Temperament.

A biologically determined pattern of emotional reactivity and regulation unique to an individual; includes the degree of emotionality, irritability and activity level, and reactions to and ability to cope with emotional situations, new impressions and changes; see easy temperament, difficult temperament and slow-to-warm-up.

Teratogens.

Substances that can cause damage to the fetus.

Terrible twos.

Common term for the period between 18 and 36 months, when children often are disobedient and defiant toward their parents.

Test.

Measurement instrument; a collection of questions or tasks that provide a basis for assessing an individual’s performance relative to peers or a specific set of criteria; see criterion-referenced test and norm-referenced test.

Thanatos.

According to psychoanalytic theory, the aggressive and destructive drive that together with libido motivates all human action.

The new theory.

A common term for Piaget’s final revision of his theory of cognitive development, which makes allowances for some of the criticism directed at the standard theory, in particular issues concerning Piaget’s assumptions on domain-general development.

The standard theory.

A common term for Piaget’s theory of cognitive development as it appeared in its basic form in the 1950s and 1960s; see the new theory.

Theory of mind.

The understanding that human beings are thinking and sentient beings who act according to how they perceive a given situation; see social cognition and mind understanding.

Toddlerhood.

Age 1–3.

Transactional model.

Developmental model based on mutual interaction between an individual and the environment over time: the environment changes the individual, the individual changes the environment, which in turn changes the individual, and so on.

Transaction effect.

The result of reciprocal influences between an individual and the environment over time, see main effect and interaction effect.

Transitive relation.

Relation that makes it possible to infer the relation between A and C based on the relations A–B and B–C, for example that A must be greater than C when A is greater than B and B is greater than C.

Triarchic model of intelligence.

According to Sternberg, a model of intelligence with three integrated sub-theories: 1) cognition and the processes that form the basis for intelligent action, 2) experiences of relationships between the inner and the outer world, and 3) use of cognitive mechanisms to adapt to the world one lives in on a practical everyday basis.

Trisomy 21.

The most common form of Down syndrome, caused by an extra chromosome 21.

Turner syndrome.

Chromosomal abnormality caused by the presence of only a single X chromosome (X0) in females; characterized by a slightly low weight at birth, heart failure, distinctive facial features, short and chubby fingers, short stature, inability to reproduce and learning disabilities.

Twin Study.

Study comparing identical and fraternal twins who have grown up together and separately in order to shed light on the importance of genes and the environment in the development of different traits.

Typical development.

Course of development that characterizes the majority of a population; see atypical development and individual differences.

U

Unconditioned response.

See conditioning.

Unconditioned stimulus.

See conditioning.

Unconscious.

Not within the sphere of conscious attention; in psychoanalytic theory, an inaccessible part of consciousness where repressed, often anxiety-eliciting memories and desires are stored.

Under-controlled behavior.

Impulsive, disruptive and aggressive behavior; see over-controlled behavior.

Under-extension.

Use of a word more limited than its usual meaning; see over-extension.

Universal grammar.

In Chomsky’s theory, an innate grammatical device that contains the grammars of all human languages.

Universality.

General validity; phenomena that exist in all cultures, such as language.

Unpopular children (sociometry).

Children who are actively rejected by other children; some children in this group appear particularly aggressive and hostile, others are socially withdrawn and often submissive, while others yet are immature and childish compared with their peers; see controversial children, neglected children, neutral children and popular children.

V

Validity.

The soundness or factual accuracy of knowledge; whether a given method measures what it aims measure and whether the results provide answers to the research questions posed.

Variation set.

A set of statements that express the same information in slightly different ways; common in child-directed speech.

Vertical décalage.

According to Piaget, the transition from one stage to another; see horizontal décalage.

Vertical relation.

Relationship in which one part has more knowledge and social power than the other, such as parent-child; see horizontal relation.

Vertical structure (in language).

Early utterances consisting of several words that do not lie within the same intonation contour, but have short pauses between them; see horizontal structure, intonation and successive one-word utterances.

Visual perspective.

Ability to understand what others are able or unable to see.

Vocable.

Vocalization of a speech-like sound without conventional meaning in the child’s language environment; typically occurs during early language development.

Vocabulary spurt.

A rapid increase in productive vocabulary that typically characterizes children’s language from the end of the second year of life; often defined as the first month in which a child’s vocabulary increases by 15 words or more, often coinciding with the child’s earliest two-word utterances.

Vulnerability.

An individual’s susceptibility to be adversely affected by particular conditions or circumstances in the environment; see resilience and risk.

W

Williams syndrome.

Genetic syndrome characterized by heart defects, distinctive facial features, a short stature, developmental delays in the fetal stage and later, problems thriving during infancy, mild or moderate learning disabilities, good language abilities compared with other skills, and trusting behavior toward other people.

Working memory.

Part of the memory system related to what an individual does while trying to remember something for a short period of time or dealing with a problem. Characterized by limited storage and processing capacity, and a rapid reduction in content if not repeated; see autobiographical memory, episodic memory, long-term memory, and semantic memory.

Working model (in social relations).

Mental representation of an early relationship that forms the basis for expectations about the nature of social relationships, such as a caregiver’s inclination to provide emotional support and be devoted and reliable.

Z

Zone of proximal development.

Children’s mastery of skills in collaboration with more competent individuals within a specific area of knowledge or expertise, as opposed to self-mastery; see scaffold.

Zygote.

Cell resulting from the fusion of an egg and a sperm cell.