Click on a letter to find a definition.

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A

Accommodation - Modifying an existing schema to fit a new experience.

achievement motivation - A person’s tendency to strive for successful performance, to evaluate her performance against standards of excellence, and to feel pleasure at having performed successfully.

acquired immune deficiency syndrome (AIDS) - A viral disease that attacks the body’s immune systems; transmitted to a foetus or newborn in the form of the human immunodeficiency virus (HIV), this disorder weakens the child’s immune system and may ultimately cause its death.

active genetic–environmental interaction - A kind of interaction in which people’s genes encourage them to seek out experiences compatible with their inherited tendencies.

activity theory - The theory that successful ageing involves maintaining interest in activities into late adulthood.

adaptation - Adjusting one’s thinking to fit with environmental demands.

aetiology - In medicine and psychiatry, the cause or causes of a specific disorder.

age cohort - People born within the same generation.

age of viability - The age of 22 to 26 weeks from conception, at which point the foetus’s physical systems are advanced enough that it has a chance to survive if born prematurely
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aggression - Behaviour that intentionally harms other people by inflicting pain or injury on them.

aggressive rejected children - Rejected children who have low self-control, are highly aggressive and exhibit behaviour problems.

allele - Alleles are alternative forms of a gene. An individual typically has two alleles – one from the mother and one from the father.

altruism - An unselfish concern for the welfare of others.

amniotic sac - A membrane that contains the developing organism and the amniotic fluid around it; sac and fluid protect the organism from physical shocks and temperature changes.

androgynous - Possessing both feminine and masculine psychological characteristics.

andropause - The ‘male menopause’, linked to a decline in the production of testosterone but with varying symptoms and not universally acknowledged to exist.

animistic thinking - The attribution of life to inanimate objects.

approach/avoidance behaviour - A pattern of interaction in which the infant or child shows an inconsistent pattern of approaching and retreating from a person or an object.

assimilation - Applying an existing schema to a new experience.

associative learning - According to Jensen, lower-level learning tapped in tests of such things as short-term memorization and recall, attention, rote learning, and simple associative skills. Also called level I learning.

attachment - A strong emotional bond that forms between infant and caregiver in the second half of the child’s first year.

Attachment Q Sort (AQS) - An assessment method in which a caregiver or observer judges the quality of a child’s attachment based on the child’s behaviour in naturalistic situations, often including brief separations from parents. Attention. The identification and selection of particular sensory input for more detailed processing.

attention deficit/hyperactivity disorder (ADHD) - A childhood disorder characterized by a persistent pattern of inattention and hyperactivity or impulsivity that far exceeds such behaviours observed in children at comparable levels of development.

authoritarian parenting - Parenting that is harsh, unresponsive and rigid, and in which parents tend to use power-assertive methods of control.

authoritative parenting - Parenting that is warm, responsive and involved yet unintrusive, and in which parents set reasonable limits and expect appropriately mature behaviour from their children.

autistic disorder - A lifelong disorder in which children’s ability to communicate and interact socially is seriously impaired; children with autism have specific language deficiencies, demonstrate a need for sameness in their environment, and often engage in repetitive and stereotyped kinds of behaviours.

autobiographical memory - A collection of memories of things that have happened to a person at a specific time or place.

automatization - The process of transforming conscious, controlled behaviours into unconscious and automatic ones.

autosomes - The 22 paired non-sex chromosomes.

average children - Children who have some friends but who are not as well liked as popular children.

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B

basic reflex activity - An infant’s exercise of, and growing proficiency in, the use of innate reflexes.

behaviour therapy - A psychological form of treatment, often used in treating conduct disorders, which is based on such learning principles as reinforcement and social learning.

behavioural genetics - The field of study that examines the role of genetics in human (and animal) behaviour.

behaviourism - A school of psychology prominent in the early twentieth century, which emphasized the role of learning in human behaviour and attempted to describe behaviour in such terms.

binocular disparity - The sense of a third spatial dimension, that of depth, produced by the brain’s fusion of the separate images contributed by each eye, each of which reflects the stimulus from a slightly different angle.

brain hemispheres - The two halves of the brain’s cerebrum, left and right.

brain reserve hypothesis - The suggestion that social and cognitive stimulation can help to build up reserves of ability, and improve brain function and performance in older adults.

Brazelton Neonatal Assessment Scale - A scale containing a battery of tests used to measure an infant’s sensory and perceptual capabilities, motor development, range of states and ability to regulate these states, as well as whether the brain and central nervous system are properly regulating involuntary responses.

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C

Caesarean delivery - The surgical delivery of a baby; the baby is removed from the mother’s uterus through an incision made in her abdomen and uterus in a procedure also known as Caesarean section.

canalization - The genetic restriction of a phenotype to a small number of developmental outcomes, permitting environmental influences to play only a small role in these outcomes.

case study - A form of research in which investigators study an individual person or group very intensely.

catch-up growth - The tendency for human beings to regain a normal course of physical growth after injury or deprivation.

categorical speech perception - The tendency to perceive as the same a range of sounds belonging to the same phonemic group.

catharsis - Discharging aggressive impulses by engaging in actual or symbolic aggressive acts that do not impinge on another person.

central executive - The overarching controller in the working model, which regulates the action of the various slave systems. This is similar to the concept of executive function.

centration - Focusing one’s attention on only one dimension or characteristic of an object or situation.

cephalocaudal - The pattern of human physical growth in which development begins in the area of the brain and proceeds downwards to the trunk and legs.

cerebral cortex - The covering layer of the cerebrum that contains the cells that control specific functions such as seeing, hearing, moving and thinking.

cerebrum - The two connected hemispheres of the brain.

chromosomes - Threadlike structures, located in the nucleus of a cell, that carry genetic information to help direct development.

classical conditioning - A type of learning in which two stimuli are repeatedly presented together until individuals learn to respond to the unfamiliar stimulus in the same way they respond to the familiar stimulus.

clique - A voluntary group formed on the basis of friendship.

codominance - A genetic pattern in which heterozygous alleles express the variants of the trait for which they code simultaneously and with equal force.

cognition - The mental activity through which human beings acquire and process knowledge.

cognitive behaviour therapy - A group therapy technique particularly useful in treating depression in adolescents. Therapeutic goals include reducing self-consciousness and feelings of being different, and teaching strategies for dealing with depressive moods and for acquiring a more positive outlook and improving social interactions.

cognitive developmental theory - Kohlberg’s theory that children use physical and behavioural clues to differentiate gender roles and to gender-type themselves very early in life, and that gender development is underpinned by the development of cognitive abilities.

cognitive developmental view of attachment - The view that to form attachments infants must differentiate between mother and stranger, and understand that people exist independent of the infant’s interaction with them.

cognitive learning - According to Jensen, higher-level learning tapped in tests of such things as abstract thinking, symbolic processing and the use of language in problem solving. Also called level II learning.

cognitive strategies - Cognitive activities used to enhance mental performance.

community of learners - An approach to classroom learning in which adults and children work together in shared activities, peers learn from one another, and the teacher serves as a guide.

comorbidity - The co-occurrence of two or more problem behaviours.

concrete operations - Subperiod in which the child is able to reason logically about materials that are physically present.

conduct disorder - A disorder characterized by a repetitive and persistent pattern of behaviour in which a young person violates the basic rights of others, or major age-appropriate societal norms or rules.

conscience - The child’s internalized values and standards of behaviour.

conservation - The understanding that altering an object’s or a substance’s appearance does not change its basic attributes or properties.

construal level theory of psychological distance - The theory that the ways in which we think about people, events or objects is more or less abstract depending on our psychological distance from them.

constructivism - The idea that children actively create their understanding of the world as they engage with new information and attempt to understand it.

consummate love - The ideal love, in Sternberg’s theory, including intimacy, passion and commitment

continuity theory - The theory that maintaining activity to a level that ensures life satisfaction is optimal for successful ageing.

continuous development - A pattern of development in which abilities change in a gradual and smooth way.

control group - In an experiment, the group that is not exposed to the treatment, or the independent variable.

control phase - According to Kopp, the first phase in learning self-regulation, when children are highly dependent on caregivers to remind them about acceptable behaviours.

controversial children - Children who are liked by many peers but also disliked by many.

conventional level - Kohlberg’s second level of moral development, in which the child’s behaviour is designed to solicit others’ approval and maintain good relations with them. The child accepts societal regulations unquestioningly and judges behaviour as good if it conforms to these rules.

coordination of secondary circular reactions - An infant’s combination of different schemas to achieve a specific goal (sometimes referred to as means–end coordination).

core knowledge - Ways of reasoning about ecologically important objects and events, such as the solidity and continuity of objects.

corpus callosum - The band of nerve fibres that connects the two hemispheres of the brain.

correlational method - A research design that permits investigators to establish relations among variables as well as assess the strength of those relations.

critical period - A period of development (age range) at which specific experiences are vital for development to occur in a typical way.

crossing over - The process by which equivalent sections of homologous chromosomes switch places randomly, shuffling the genetic information each carries.

crossmodal matching paradigms - Tasks that examine whether participants can match an object according to its unimodal properties. For instance, one could examine if an infant can match a cube presented to his hands with a visual cube by examining where he looks when presented with both a cube and a distracter stimulus, such as a triangle.

crossmodal perception - The integration of sensory information from more than one modality.

cross-sectional method - A research method in which researchers compare groups of individuals of different age levels at approximately the same point in time.

crowd - A collection of people whom others have stereotyped on the basis of their perceived shared attitudes or activities – for example, ‘populars’ or ‘nerds’.

crystallized intelligence - Aspects of intelligence related to knowledge, education and experience, such as knowing what a particular word means.

cumulative risk - The notion that risk factors in children’s life circumstances have cumulative negative effects on their intellectual performance.

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D

debriefing - Communicating the findings of research, or its purpose, to participants after a study has been completed.

deductive reasoning - Logical thinking that involves reaching a necessary and valid conclusion based on a set of premises.

deferred imitation - Mimicry of an action some time after having observed it; requires that the child have some sort of mental representation of the action.

deoxyribonucleic acid (DNA) - A ladder-like molecule that stores genetic information in cells and transmits it during reproduction.

dependent variable - The variable, or factor, that researchers expect to change as a function of change in the independent variable.

depression in childhood - Like adult depression, a mood disorder often manifested in a depressed mood and loss of interest in familiar activities, but also likely to be expressed as irritability and crankiness. Difficulty concentrating or focusing on tasks and concomitant drops in school grades are not uncommon, and children with depression often complain of physical problems such as headache.

developmental psychology - field of study that seeks to understand and explain change in individuals’ cognitive, social and other capacities, first by describing changes in the child’s observed behaviours and second by uncovering the processes that underlie these changes.

developmental psychopathology - The investigation of the origins, course, changes and continuities in disordered or maladaptive behaviour over a person’s life span.

deviation IQ - n IQ score that indicates the extent to which a person’s performance on a test deviates from age mates’ average performance.

diagnosis - The identification of a physical or mental disorder on the basis of symptoms and of knowledge of the cause or causes of the disorder and its common course. A diagnosis may also include information about effective forms of treatment.

diagnostic reliability - A measure of how often two or more clinicians arrive independently at the same diagnosis of a particular disorder.

diethylstilbestrol (DES) - A synthetic hormone once prescribed for pregnant women to prevent miscarriage, but discontinued when cancer and precancerous conditions were detected in their children.

discontinuous development - A pattern of development in which changes occur suddenly, resulting in qualitatively different stages (periods) of development.

disengagement theory - The theory that successful ageing involves a gradual retreat and withdrawal from many activities.

dizygotic - Characterizing fraternal twins, who have developed from two separate fertilized eggs.

domain-general development - The idea that developments can have impact on a wide range of abilities.

domain-specific development - The idea that the development of various abilities occurs independently (separately) and has little impact on skills in other domains.

dominant - The more powerful of two alleles in a heterozygous combination.

dopamine - A neurohormone involved in the motivation of motor behaviour.

dyslexia (a) - A term for the difficulties some people experience in reading or in learning to read.

dyslexia (b) - A learning disability that impairs the ability to read and spell fluently.

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E

ecological perspective - A perspective that stresses the importance of understanding not only the relationships between organisms and various environmental systems but also the relations among such systems themselves.

ecological validity - The degree to which a research study accurately represents events or processes that occur in the natural world.

ego - In Freudian theory, the rational, controlling component of the personality, which tries to satisfy needs through appropriate, socially acceptable behaviours.

egocentric speech - According to Vygotsky, a form of self-directed dialogue by which the child instructs herself in solving problems and formulating plans; as the child matures, this becomes internalized as inner speech.

egocentrism - The tendency to view the world from one’s own perspective and to have difficulty seeing things from another’s viewpoint.

elaboration - A memory strategy in which one adds to information to make it more meaningful and thus easier to remember.

elementary mental functions - Psychological functions with which the child is endowed by nature, including attention, perception and involuntary memory, which emerge spontaneously during children’s interaction with the world.

embryo - The developing organism, which, implanted in the uterus wall, undergoes rapid cell division resulting in the differentiation of the major physiological structures and systems.

embryonic stage - The period of prenatal development lasting from the second to around the eighth week of gestation.

emotional display rules - Rules that dictate which emotions one may appropriately display in particular situations.

emotional script - A complex scheme that enables a child to identify the emotional reaction likely to accompany a particular sort of event.

emotions - Subjective reactions to the environment that are usually experienced cognitively as either pleasant or unpleasant, generally accompanied by physiological arousal, and often expressed in some visible form of behaviour.

empathic - Able to experience the same emotion that someone else is experiencing.

empathy - The capacity to experience the same emotion that someone else is experiencing.

empiricism - The idea that development is primarily determined by environmental influences.

encoding - The transformation of information from the environment into a mental representation.

epigenetics - The study of how genetic material is expressed.

episodic memory - Memory for specific events, often autobiographical in nature.

ethnic awareness - The understanding of ethnicity as a social category.

ethological theory - A theory which holds that behaviour must be viewed and understood as occurring in a particular context and as having adaptive or survival value.

ethological theory of attachment - Bowlby’s theory that attachment derives from the biological preparation of both infant and parents to respond to one another’s behaviours in such a way that parents provide the infant with care and protection.

evocative genetic–environmental interaction - The expression of the genes’ influence on the environment through an individual’s inherited tendencies to evoke certain environmental responses; for example, a child’s smiling may elicit smiles from others.

evolutionary psychology - An approach which holds that critical components of psychological functioning reflect evolutionary changes and are critical to the survival of the species.

executive control process - A cognitive process that serves to control, guide and monitor the success of a problem-solving approach a child uses.

executive control structure - According to Case, a mental blueprint or plan for solving a class of problems.

executive function - A cognitive system that is presumed to control and manage other cognitive processes.

expansion - A technique adults use in speaking to young children in which they imitate and expand or add to a child’s statement.

experimental group - In an experiment, the group that is exposed to the treatment, or the independent variable.

expressive characteristics - Presumably typical of females, these characteristics include nurturance and concern with feelings.

extended family - A family that includes relatives such as grandparents, aunts, uncles, nieces and nephews within the basic family unit of parents and children.

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F

factor analysis - A statistical procedure used to determine which of a number of factors, or scores, are both closely related to one another and relatively independent of other groups of factors, or scores.

fatuous love - Passion and commitment without intimacy.

field experiment - An experiment in which researchers deliberately create a change in a real-world setting and then measure the outcome of their manipulation.

fluid intelligence - The capacity for abstract reasoning, such as spotting patterns of numbers or sequences.

foetal alcohol syndrome - A disorder of the developing foetus caused by the ingestion of alcohol by the foetus’s mother during gestation. It is characterized by stunted growth, a number of physical and physiological abnormalities and, often, mental retardation.

foetus - The developing organism from the third month of gestation through delivery; during the foetal period, bodily structures and systems develop to completion.

formal operations stage - Stage in which the child becomes capable of abstract thinking, complex reasoning and hypothesis testing.

fragile X syndrome - A form of chromosomal abnormality, more common in males than in females, in which an area near the tip of the X chromosome is narrowed and made fragile due to a failure to condense during cell division. Symptoms include physical, cognitive and social problems.

friendship - A reciprocal commitment between two people who see themselves more or less as equals.

fusiform face area - An area of the temporal lobes that is strongly involved in face recognition.

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G

gender constancy - The awareness that superficial alterations in appearance or activity do not alter gender.

gender identity - The perception of oneself as either masculine or feminine.

gender roles - Composites of the behaviours actually exhibited by a typical male or female in a given culture; the reflection of a gender stereotype in everyday life.

Gender Schema Theory - An information processing approach to gender development which suggests that schemas help children to organize and structure their experience related to gender differences and gender roles.

gender stability - The notion that gender does not change; males remain male and females remain female.

gender stereotypes - Beliefs that members of a culture hold about how females and males should behave; that is, what behaviours are acceptable and appropriate for each sex.

gender typing - The process by which children acquire the values, motives and behaviours considered appropriate for their gender in their particular culture.

gene - A portion of DNA located at a particular site on a chromosome and that codes for the production of certain kinds of proteins.

generalization - The application of a strategy learned while solving a problem in one situation to a similar problem in a new situation.

genital herpes - A common viral infection spread primarily through sexual contact; if contracted by an infant during birth, it can cause blindness, motor abnormalities, mental retardation and a wide range of neurological disorders.

germinal stage - The stage of pregnancy beginning with the zygote being formed by the fertilization of the egg, and finishing when the zygote is implanted in the wall of the uterus (about seven days later).

gerontology -The study of the social, biological and psychological aspects of ageing.

gestation - The carrying of an embryo/foetus during pregnancy, usually for nine months in humans.

glial cell - A nerve cell that supports and protects neurons, and serves to encase them in myelin sheaths.

grammar - The structure of a language; consists of morphology and syntax.

grandparenting styles - Different types of grandparenting relationship identified as compassionate, involved and remote, depending on the degree of involvement with a grandchild and the quality of the relationship.

guided participation - Learning that occurs as children participate in activities of their community and are guided in their participation by the actions of more experienced partners in the setting.

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H

habituation - A form of learning instantiated in a decrease in the strength of response to a repeated stimulus.

haemophilia - A disorder, caused by an X-linked recessive gene, in which the blood fails to clot; found more often in males than in females.

hedonistic reasoning - Making a decision to perform a prosocial act on the basis of expected material reward.

hemispheric specialization - Differential functioning of the two cerebral hemispheres; the left controlling the right side of the body, the right controlling the left side.

heritability factor - A statistical estimate of the contribution heredity makes to a particular trait or ability.

heterozygous - The state of an individual whose alleles for a particular trait from each parent are different.

hierarchical categorization - The organization of concepts into levels of abstraction that range from the specific to the general.

higher mental functions - Psychological functions, such as voluntary attention, complex memory processes and problem solving, that entail the coordination of several cognitive processes and the use of mediators.

holophrase - A single word that appears to represent a complete thought.

homozygous - The state of an individual whose alleles for a particular trait from each parent are the same.

horizontal décalage - The term Piaget used to describe unevenness in children’s thinking within a particular stage; for example, in developing an understanding of conservation, children conserve different objects or substances at different ages.

hormones - Powerful and highly specialized chemical substances that are produced by the cells of certain body organs and that have a regulatory effect on the activity of certain other organs.

hostile aggression - Directing aggressive behaviour at a particular person or group, criticizing, ridiculing, telling tales or calling names.

human behavioural genetics - The study of the relative influences of heredity and environment on the evolution of individual differences in traits and abilities.

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I

iconic memory - Sensory memory for visual information. Of very short duration.

id - In Freudian theory, the person’s instinctual drives; the first component of the personality to evolve, the id operates on the basis of the pleasure principle.

imprinting - The process by which birds and other infrahuman animals develop a preference for the person or object to which they are first exposed during a brief, critical period after birth.

independent variable - The variable, or factor, that researchers deliberately manipulate in an experiment.

infant-directed, or child-directed, speech - A simplified style of speech parents use with young children, in which sentences are short, simple and often repetitive, and the speaker enunciates especially clearly, slowly and in a higher-pitched voice, often ending with a rising intonation. Also called motherese.

infant state - A recurring pattern of arousal in the newborn, ranging from alert, vigorous, wakeful activity to quiet, regular sleep.

infantile amnesia - The inability to remember any event or piece information encoded before the age of around 3 years.

infatuation - A relationship based only on passion (i.e. without intimacy or commitment).

information-processing approaches - Theories of development that focus on the flow of information through the child’s cognitive system and particularly on the specific operations the child performs between input and output phases.

informed consent - Agreement, based on a clear and full understanding of the purposes and procedures of a research study, to participate in that study.

inner speech - Internalized egocentric speech that guides intellectual functioning.

insecure-avoidant attachment - A type of attachment shown by babies who seem not to be bothered by their mothers’ brief absences but specifically avoid them on their return, sometimes becoming visibly upset.

insecure-disorganized attachment - A type of attachment shown by babies who seem disorganized and disorientated when reunited with their mothers after a brief separation.

insecure-resistant attachment - A kind of attachment shown by babies who tend to become very upset at the departure of their mothers and who exhibit inconsistent behaviour on their return, sometimes seeking contact, sometimes pushing their mothers away.

instrumental aggression - Quarrelling and fighting with others over toys and possessions.

instrumental characteristics - Presumably typical of males, these characteristics include task and occupation orientation.

intellectual giftedness - A characteristic defined by an IQ score of 130 or over; gifted children learn faster than others and may show early exceptional talents in certain areas.

intelligence quotient (IQ) - An index of the way a person performs on a standardized intelligence test relative to the way others her age perform.

intent community participation - Children’s participation in the authentic activities of their community with the purpose of learning about the activity.

internal working model - According to Bowlby, a person’s mental representation of himself as a child, his parents and the nature of his interaction with his parents, as he reconstructs and interprets that interaction; also referred to as an attachment representation.

interposition - The sense that one object is in front of another, provided by the partial occlusion of the further object by the nearer object.

inventing new means by mental combination - Children begin to combine schemas mentally, and rely less on physical trial and error.

iron-deficiency anaemia - A disorder in which inadequate amounts of iron in the diet causes listlessness, and may retard a child’s physical and intellectual development.

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J

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K

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L

laboratory experiment - A research design that allows investigators to determine cause and effect by controlling variables and treatments, and assigning participants randomly to treatments.

language - A communication system in which words and their written symbols combine in rule-governed ways and enable speakers to produce an infinite number of messages.

language acquisition device (LAD) - Chomsky’s proposed mental structure in the human nervous system, which incorporates an innate concept of language.

language acquisition support system (LASS) - A collection of strategies and tactics that environmental influences – initially, a child’s parents or caregivers – provide to the language-learning child.

lateralization - The process by which each half of the brain becomes specialized for certain functions – for example, the control of speech and language by the left hemisphere and of visual-spatial processing by the right.

learned helplessness - A kind of behaviour that results from the belief that one is helpless to control the events in one’s world.

learning disabilities - Deficits in one or more cognitive processes important for learning.

learning theory of attachment - The theory that infants become attached to their mothers because a mother provides food, or primary reinforcement, and thus becomes a secondary reinforcer.

level of explanation - The way in which we choose to describe psychological abilities (and the developments of those abilities). Levels of explanation can include biological, behavioural, social and emotional.

life structure - The underlying pattern of an adult’s life at a particular point in life.

lifespan perspective - A view of development as a process that continues throughout the life cycle, from infancy through adulthood and old age.

linear perspective - The manner in which patterns of light fall on the eye from objects that recede in depth.

longitudinal method - A method in which investigators study the same people repeatedly at various times in the participants’ lives.

long-term memory - The mental processing unit in which information may be stored permanently, and from which it may later be retrieved.

low birth weight - A term describing a premature baby who may be born close to its due date but who weighs significantly less than would be appropriate to its gestational age.

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M

maturational approach - An early approach to explaining development in terms of maturational timetables, predetermined by genetic inheritance.

mediational deficiency - Inability to use strategies to store information in long-term memory.

mediators - Psychological tools and signs – such as language, counting, mnemonic devices, algebraic symbols, art and writing – that facilitate and direct thinking processes.

meiosis - The process by which a cell divides to produce new reproductive cells with only half the normal complement of chromosomes; thus male and female reproductive cells (sperm and ovum) each contain only 23 chromosomes so that, when they unite, the new organism they form will have 46 chromosomes, half from each parent.

memory span - The amount of information one can hold in short-term memory.

menarche - In females, the beginning of the menstrual cycle.

menopause - A biological change in women during middle adulthood where the ovaries cease functioning and women can no longer conceive children.

mental representation - Information stored mentally in some form (e.g. verbal, pictorial, procedural).

mental retardation - A characteristic defined by an IQ score below 70 together with difficulty in coping with age-appropriate activities of everyday life.

messenger ribonucleic acid (mRNA) - Molecules that transcribe the genetic code in DNA in the nucleus of the cell, and then travel to the body of the cell, where they are then used to synthesize protein.

metacognition - The individual’s knowledge about knowing and his control of cognitive activities.

metalinguistic awareness - The understanding that language is a rule-bound system of communicating.

microgenetic change - Changes associated with learning that occur over the time of a specific learning experience or episode.

miscarriage - The natural or spontaneous end of a pregnancy before the infant is capable of survival outside the womb. Human infants are generally unable to survive outside the uterus prior to 20 weeks’ gestation.

mitosis - The process in which a body cell divides in two, first duplicating its chromosomes so that the new daughter cells produced each contain the usual 46 chromosomes.

modal model - A model of information processing in which information moves through a series of organized processing units: sensory register, short-term memory and long-term memory. The modal model emphasizes the importance of storage capacity and duration.

monozygotic - Characterizing identical twins, who have developed from a single fertilized egg.

moral realism - Piaget’s second stage of moral development, in which the child shows great respect for rules but applies them quite inflexibly.

morality of reciprocity - Morality in which moral judgements should be made on the basis of equality and fairness between people, and equal justice for all.

morphology - The study of morphemes, language’s smallest units of meaning.

motion parallax - A cue to depth emerging from the fact that, when we move, objects that are further away move across our visual field more slowly than do objects that are closer to us

myelination - The process by which glial cells encase neurons in sheaths of the fatty substance myelin.

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N

narrative form - A temporally sequenced account that conveys meaning about an event.

nativism - The idea that development is primarily determined by inherited factors (i.e. genetics).

natural experiment - An experiment in which researchers measure the results of events that occur naturally in the real world.

needs-orientated reasoning - Reasoning in which children express concern for others’ needs even though their own needs may conflict with those needs.

neglected children - Children who are often socially isolated and, although they are not necessarily disliked by others, have few friends.

neonate - A newborn baby.

neo-Piagetian theories - Theories of cognitive development that reinterpret Piaget’s concepts from an information-processing perspective.

neural migration - The movement of neurons within the brain, which ensures that all brain areas have a sufficient number of neural connections.

neural proliferation - The rapid formation of neurons in the developing organism’s brain.

neural tube - This structure, which is formed by the ectoderm (a layer of cells in the embryo) folding in on itself, develops into the nervous system, via a processes of cell differentiation, along its extent.

neuron - A cell in the body’s nervous system, consisting of a cell body, a long projection called an axon and several shorter projections called dendrites; neurons send and receive neural impulses, or messages, throughout the brain and nervous system.

neuronal death - The death of some neurons that surround newly formed synaptic connections among other neurons; also called programmed cell death.

niche picking - Seeking out or creating environments compatible with one’s genetically based predispositions.

non-aggressive rejected children - Rejected children who tend to be anxious, withdrawn and socially unskilled.

non-shared environment - A set of conditions or activities experienced by one child in a family but not shared with another child in the same family.

nuclear family - A family composed of two parents and one or more children, in which the father is the breadwinner and the mother the homemaker.

nucleotide - A compound containing a nitrogen base, a simple sugar and a phosphate group.

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O

obesity - A condition in which a person’s weight is 30% or more in excess of the average weight for his or her height and frame.

object permanence - The notion that entities external to us, such as objects and people, continue to exist independent of our seeing or interacting with them.

observation - A method in which researchers go into settings in the natural world or bring participants into the laboratory to observe behaviours of interest.

observer bias - The tendency of observers to be influenced in their judgements by their knowledge of the hypotheses guiding the research.

obsessive self-stimulatory behaviour - Behaviour common in children with autism in which they engage in repetitive actions that seemingly have no purpose.

oestrogens - Hormones that, in the female, are responsible for sexual maturation.

operant behaviour therapy - A form of behaviour therapy in which behaviour is carefully monitored and consistently rewarded with such things as food.

operant conditioning - A type of learning that depends on the consequences of behaviour; rewards increase the likelihood that a behaviour will recur, whereas punishment decreases that likelihood.

operations - Schemas based on internal mental activities.

organization (a) - Combining simple mental structures into more complex systems.

organization (b) - A memory strategy that involves putting together in some organized form the information to be remembered; usually entails categorization and hierarchical relations.

overcontrolled disorders - A group of psychological disturbances in which a child appears overly controlled, withdrawing from others, lacking spontaneity and generally appearing to be not a happy child.

overextension - The use, by a young child, of a single word to cover many different things.

overregularization - The application of a principle of regular change to a word that changes irregularly.

ovum - The female reproductive cell, or egg.

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P

parahippocampal place area - An area in the temporal lobe (surrounding the hippocampus), which is strongly involved in forming representations of visual scenes.

passive genetic–environmental interaction - The interactive environment created by parents with particular genetic predispositions who encourage the expression of these tendencies in their children.

peer-group network - The cluster of peer acquaintances who are familiar with and interact with one another at different times for common play or task-orientated purposes.

peer victimization - Ill treatment of one child by another (or by others) that can range from teasing to bullying to serious physical harm; typically, victimizing is a continuing behaviour that persists over time.

perinatal complications - Difficulties surrounding the birth of a child, which can lead to developmental difficulties.

perinatal risk factors - Factors that can contribute to perinatal complications.

permissive parenting - Parenting that is lax, and in which parents exercise inconsistent discipline and encourage children to express their impulses freely.

pervasive developmental disorders (PDD) - Childhood disorders characterized by gross deficits in many areas of cognitive, emotional and social development that are linked with severe and pervasive impairment of social interaction and communication skills.

phenylketonuria (PKU) - A disease caused by a recessive allele that fails to produce an enzyme necessary to metabolize the protein phenylalanine; if untreated immediately at birth, damages the nervous system and causes mental retardation.

phonological awareness - The understanding of the sounds of a language and of the properties, such as the number of sounds in a word, related to these sounds.

phonological loop - A ‘slave system’ in the working memory model that deals with speech sound information.

phonology - The system of sounds that a language uses.

Piagetian theory - A theory of cognitive development that sees the child as actively seeking new information.

pituitary gland - A so-called master gland, located at the base of the brain, which triggers the secretion of hormones by all other hormone-secreting (endocrine) glands.

placenta - A fleshy, disk-like structure formed by cells from the lining of the uterus and from the zygote that, together with the umbilical cord, serves to protect and sustain the life of the growing organism.

planning - The deliberate organization of a sequence of actions orientated towards achieving a goal.

plasticity - The capacity of the brain, particularly in its developmental stages, to respond and adapt to input from the external environment.

pleiotropy - A gene is pleiotropic if it is expressed differently in different parts of the brain.

popular children - Children who are liked by many peers and disliked by very few.

postconventional level - Kohlberg’s third level of moral development, in which the child’s judgements are rational, and his conduct is controlled by an internalized ethical code that is relatively independent of the approval or disapproval of others.

postformal thinking - Thought based on logical solutions but recognizing the role of relative perspectives and context in making judgements.

pragmatics - A set of rules that specify appropriate language for particular social contexts.

preconventional level - Kohlberg’s first level of moral development, in which he sees the child’s behaviour as based on the desire to avoid punishment and gain rewards.

prejudice - An attitude, or set of attitudes, which is often based on stereotypes towards a particular group, and is usually negative.

premoral stage - Piaget’s first stage of moral development, in which the child shows little concern for rules (also referred to as the amoral stage).

preoperational representations - In this subperiod, the ability to use symbols facilitates the learning of language; this stage is also marked by pre-logical reasoning, egocentricity – in which the child sees the world from her own point of view – and intuitive behaviour, in which the child can solve problems using mental operations but cannot explain how she did so.

pre-programmed theory (or Dev-Age) - The theory that our rate of physical ageing is set by our genes, and is therefore, in large part, inevitable.

preterm - A term describing a premature baby that is born before its due date and whose weight, although less than that of a full-term infant, may be appropriate to its gestational age.

primary ageing - The gradual deterioration in physical ability due to genetic or ‘pre-programmed’ factors.

primary circular reactions - Behaviours focused on the infant’s own body that the infant repeats and modifies because they are pleasurable and satisfying.

proactive aggression - The use of force to dominate another person or to bully or threaten others.

problem solving - The identification of a goal and of steps to reach that goal.

production deficiency - Inability to generate and use known memory strategies spontaneously.

productive language - The production of speech.

progesterone - A hormone that, in females, helps regulate the menstrual cycle, and prepares the uterus to receive and nurture a fertilized egg.

propositional reasoning - Logical thinking that involves evaluating a statement or series of statements based on the information in the statement alone.

prosocial behaviour - Behaviour designed to help or benefit other people.

prosocial reasoning - Thinking and making judgements about prosocial issues.

protodeclarative - A gesture that an infant uses to make some sort of statement about an object.

protoimperative - A gesture that either an infant or a young child may use to get someone to do something she or he wants.

proximal-distal - The pattern of human physical growth wherein development starts in central areas, such as the internal organs, and proceeds to more distant areas, such as arms and legs.

psychoanalytic theory of attachment - Freud’s theory that babies become attached first to the mother’s breast and then to the mother herself as a source of oral gratification.

psychodynamic approach - The set of theories based on Freud’s stage model of development, with movement through stages usually marked by the resolution of some form of conflict.

psychodynamic theory - In this view of development, which is derived from Freudian theory, development occurs in discrete stages and is determined largely by biologically based drives shaped by encounters with the environment and through the interaction of the personality’s three component: the id, ego and superego.

psychosocial theory - Erikson’s theory of development, which sees children developing through a series of stages largely through accomplishing tasks that involve them in interaction with their social environment.

psychostimulant medications - Drugs, such as amphetamines and caffeine, that increase alertness and attention as well as psychomotor activity.

puberty - The onset of sexual maturity.

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Q

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R

random assignment - The technique by which researchers assign individuals randomly to either an experimental or control group.

range of reaction - The notion that the human being’s genetic makeup establishes a range of possible developmental outcomes, within which environmental forces largely determine how the person actually develops.

reactive aggression - Aggressive behaviour as a response to attack, threat or frustration.

recast - A technique adults use in speaking to young children in which they render a child’s incomplete sentence in a more complex grammatical form.

receptive language - Understanding the speech of others.

recessive - The weaker of two alleles in a heterozygous combination.

reciprocal instruction - A tutoring approach based on the ideas of the zone of proximal development and scaffolding.

reflex - An involuntary response to external stimulation.

reflex smile - A smile seen in the newborn that is usually spontaneous and appears to depend on some internal stimulus rather than on something external such as another person’s behaviour.

regulation factor - A substance that influences non-protein-coding DNA to regulate transcription of protein-coding DNA into mRAN and, later, protein
.
rehearsal - A memory strategy in which one repeats a number of times the information one wants to remember, either mentally or orally.

rejected children - Children who are disliked by many peers and liked by very few.

relational aggression - Damaging or destroying interpersonal relationships by such means as excluding another or gossiping about or soiling another’s reputation.

relational victimization - The attempt by a peer to damage or control another child’s relationships with others.

relationship - A continuing succession of interactions between two people that are affected by their shared past interactions, and that also affect their future interactions.

REM sleep - REM, or rapid eye movement, sleep is characterized by rapid, jerky movements of the eyes and, in adults, is often associated with dreaming.

representativeness - The degree to which a sample actually possesses the characteristics of the larger population it represents.

reputational bias - Children’s tendency to interpret peers’ behaviour on the basis of past encounters with and feelings about them.

reserve capacity - The capacity to push one’s body a little further if undertaking strenuous physical activities.

reversibility - The understanding that the steps of a procedure or operation can be reversed, and that the original state of the object or event can be obtained.

Rh factor incompatibility - A condition in which an infant’s Rh-negative blood opposes its mother’s Rh-positive blood and which threatens foetuses in later births, when the mother’s body has had time to produce antibodies that will attack foetal blood cells.

romantic love - Intimacy and passion without commitment.

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S

sample - A group of individuals who are representative of a larger population.

scaffolding - An instructional process in which the more knowledgeable partner adjusts the amount and type of support he offers to the child to fit with the child’s learning needs over the course of the interaction.

schema - An organized unit of knowledge that the child uses to try to understand a situation; a schema forms the basis for organizing actions and thoughts in response to the environment.

scientific methods - The use of measurable and replicable techniques in framing hypotheses, and collecting and analysing data to test a theory’s usefulness.

script - A mental representation of an event or situation of daily life, including the order in which things are expected to happen and how one should behave in that event or situation.

secondary ageing - The deterioration of the body in light of injuries and illnesses over time.

secondary circular reactions - Behaviours focused on objects outside the infant’s own body that the infant repeatedly engages in because they are pleasurable and satisfying.

secondary reinforcer - A person or other stimulus that acquires reinforcing properties by virtue of repeated association with a primary reinforcer.

secular trend - A shift in the normative pattern of a characteristic, such as height, that occurs over a historical time period, such as a decade or century.

secure attachment - A kind of attachment displayed by babies who are secure enough to explore novel environments, who are minimally disturbed by brief separations from their mothers, and who are quickly comforted by their mothers when they return.

secure base - According to Ainsworth, a caregiver to whom an infant has formed an attachment, and whom the child uses as a base from which to explore and as a safe haven in times of stress.

selective attention - A strategy in which one focuses on some features of the environment and ignores others.

selective optimization with compensation (SOC) - The theory that, as people age and cognitive capacities decline, they seek to compensate for this decline by finding alternative ways of completing tasks.

self-control phase - According to Kopp, the second phase in learning self-regulation, when the child becomes able to comply with caregiver expectations in the absence of the caregiver.

self-delay gratification - To put off until another time possessing or doing something that gives one pleasure.

self-disclosure - The honest sharing of information of a very personal nature, often with a focus on problem solving; a central means by which adolescents develop friendships.

self-regulation phase - According to Kopp, the third phase in learning self-regulation, when children become able to use strategies and plans to direct their own behaviour and to delay gratification.

self-regulation - The child’s ability to control behaviour on her own without reminders from others.

self-report - Information that people provide about themselves, either in a direct interview or in some written form, such as a questionnaire.

semantic memory - All the world knowledge and facts a person possesses.

semantics - The study of word meanings and word combinations.

sensitive care - Consistent and responsive caregiving that begins by allowing an infant to play a role in determining when feeding will begin and end, and at what pace it will proceed.

sensitive period - A period of development (age range) at which particular experiences are important for typical development. If those experiences do not occur during that period, typical development may still occur.

sensitization - An increase in the strength of response to a repeated stimulus. Like habituation, sensitization is also classified as a simple learning mechanism as it occurs in response to only a single stimulus.

sensorimotor period - Piaget’s name for the first stage of cognitive development that he described, during which children’s abilities are rooted in their physical interactions with objects.

sensory register - The mental processing unit that takes information from the environment and stores it in original form for brief periods of time.

separation protest - An infant’s distress reaction to being separated from his or her mother, which typically peaks at about 15 months of age.

sequential method - A research method that combines features of both the cross-sectional and the longitudinal methods.

sex chromosomes - In both males and females, the 23rd pair of chromosomes, which determine the individual’s sex and are responsible for sex-related characteristics; in females, this pair normally comprises two X chromosomes, in males an X and a Y chromosome.

sexual orientation - The preference for same- or opposite-gender sexual partners.

shape constancy - The ability to perceive an object’s shape as constant despite changes in its orientation and the angle from which one views it.

shared environment - A set of conditions or experiences shared by children raised in the same family; a parameter commonly examined in studies of individual differences.

short-term memory - The mental processing unit in which information is stored temporarily; the ‘work space’ of the mind, where a decision is made to discard information, work on it or transfer it to permanent storage in long-term memory.

size constancy - The tendency to perceive an object as constant in size regardless of changes in its distance from the viewer and in the image it casts on the retinas of the eyes.

social learning theory - A learning theory that stresses the importance of observation and imitation in the acquisition of new behaviours, with learning mediated by cognitive processes.

social referencing - The process of ‘reading’ emotional cues in others to help determine how to act in an uncertain situation.

social-convention rules - Socially based rules about everyday conduct.

socially unskilled - Being unskilled at solving interpersonal problems.

sociocultural theory - A theory of development, proposed by Lev Vygotsky, that sees development as emerging from children’s interactions with more skilled people, and the institutions and tools provided by their culture.

sociometric technique - A procedure for determining children’s status within their peer group; each child in the group either nominates others whom she likes best and least, or rates each child in the group for desirability as a companion.

sperm - The male reproductive cell.

spermarche - In males, the first ejaculation of sperm-containing ejaculate.

stages of development - Comprehensive, qualitative changes over time in the way a child thinks and/or acts.

stereotype threat - Being at risk of confirming a negative stereotype about the group to which one belongs.

Strange Situation - A testing scenario in which mother and child are separated and reunited several times; enables investigators to assess the nature and quality of a mother–infant attachment relationship.

stranger distress - A fear of strangers that typically emerges in infants around the age of 9 months.

structured observation - A form of observation in which researchers structure a situation so that behaviour(s) they wish to study is/are more likely to occur.

substance abuse - The excessive use of legal or illegal drugs in such a way as to interfere seriously with one or more important area(s) of functioning in life: work, intimacy with another, or general interpersonal and social relationships.

sudden infant death syndrome (SIDS) - The sudden, unexplained death of an infant while sleeping; also called cot death.

superego - In Freudian theory, the personality component that is the repository of the child’s internalization of parental or societal values, morals and roles.

symbolic representation - The ability to use symbols, such as images, words and gestures, to represent objects and events in the world.

symbolic thought - The use of mental images and concepts to represent people, objects and events.

synapse - A specialized site of intercellular communication where information is exchanged between nerve cells, usually by means of a chemical neurotransmitter.

synaptic pruning - The brain’s disposal of the axons and dendrites of a neuron that is not often stimulated.

synaptogenesis - The forming of synapses.

syntax - The part of grammar that prescribes how words may combine into phrases, clauses and sentences.

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T

telegraphic speech - Two-word utterances that include only the words essential to convey the speaker’s intent.

teratogen - An environmental agent, such as a drug, medication, dietary imbalance or polluting substance, that may cause developmental deviations in a growing human organism; most threatening in the embryonic stage but capable of causing abnormalities in the foetal stage as well.

tertiary circular reactions - Behaviours in which infants experiment with the properties of external objects and try to learn how objects respond to various actions.

testosterone - A hormone that, in males, is responsible for the development of primary and secondary sex characteristics, and is essential for the production of sperm.

thalidomide - A drug once prescribed to relieve morning sickness in pregnant women but discontinued when found to cause serious foetal malformations. Current controversy surrounds its possible use in treating symptoms of such diseases as AIDS, cancer and Hansen’s disease (leprosy).

theory of mind - A person’s beliefs about the ‘mind’ and the ability to understand mental states.

theory of multiple intelligences - Gardner’s multifactorial theory that proposes eight distinct types of intelligence.

time out - Removing children from a situation or context in which they are acting inappropriately until they are able and ready to act appropriately.

transitive inference - The mental arrangement of things along a quantitative dimension.

triangular theory of love - Sternberg’s model of loving relationships, which includes three components – intimacy, commitment and passion – that vary in different relationship types.

triarchic theory of intelligence - A theory that proposes three major components of intelligence: information-processing skills, experience with a task, and ability to adapt to the demands of a context.

two moral worlds view - The view that there is a fundamental shift from heteronomous morality (morality is determined by adults and authority figures) to an autonomous morality (morality where we all participate and agree on moral rules as members of society).

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U

umbilical cord - A tube that contains blood vessels connecting the growing organism and its mother by way of the placenta; it carries oxygen and nutrients to the growing infant, and removes carbon dioxide and waste products.

undercontrolled disorders - A group of psychological disturbances in which a child appears to lack self-control and to ‘act up’ in a variety of ways, through such behaviours as non-compliance, disobedience and aggression.

underextension - The use, by a young child, of a single word in a restricted and individualistic way.

uninvolved parenting - Parenting that is indifferent and neglectful, and in which parents focus on their own needs rather than their children’s needs. Also known as neglecting-rejecting parenting.

‘use it or lose it’ - The idea that, to avoid cognitive or physical decline into old age, people must continue to use cognitive and physical abilities as much as possible.

utilization deficiency - Inability to use a known memory strategy or to benefit from the use of such a memory strategy.

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V

vignette - A short story that depicts a scenario or situation about which the child has to comment, discuss or make a judgement.

visual acuity - Sharpness of vision; the clarity with which fine details can be detected.

visual cliff - An apparatus that tests an infant’s depth perception by using patterned materials and an elevated, clear glass platform to make it appear that one side of the platform is several feet lower than the other.

visuospatial sketch-pad - A ‘slave system’ in the working memory model which deals with visual-spatial representations.

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W

wear-and-tear theory - The theory that ageing is due to environmental or external factors (such as injury or illness).

Wechsler Intelligence Scales - Three intelligence tests for preschool children, school-age children and adults, which yield separate scores for verbal and performance IQ as well as a combined IQ score.

working memory - A model of short-term memory processes incorporating a central executive, phonological loop (for storing auditory information), a visuospatial sketch-pad (for visual information) and an episodic buffer (for linking information across domains).

working memory model - Baddeley and Hitch’s (1976) model of human information processing, which emphasizes dynamic thought processes rather than more basic parameters like storage duration and capacity.

world knowledge - What a child has learned from experience and knows about the world in general.

X

X-linked genes - Genes that are carried on the X chromosome and that, in males, may have no analogous genes on the Y chromosome.

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Y

Z

zone of proximal development (ZPD) - The region of sensitivity for learning characterized by the difference between the developmental level of which a child is capable when working alone and the level she is capable of reaching with the aid of a more skilled partner.

zygote - The developing organism from the time sperm and egg unite to about the second week of gestation, during which the zygote undergoes rapid cell division.