A group of people who were born at about the same time and thus move through life together, experiencing the same historical events and cultural shifts at about the same age.
A group of ideas, assumptions and generalizations that interpret and illuminate the thousands of observations that have been made about human growth. A developmental theory provides a frame work for explaining the patterns and problems of development.
A grand theory of human development that holds that irrational, unconscious drives and motives, often originating in childhood, underlie human behavior
A grand theory of human development that focuses on changes in how people think over time. According to this theory, our thoughts shape our attitudes, beliefs and behaviors.
Social Learning Theory
An extension of behaviorism that emphasizes the influence that other people have over a person's behavior. Even without specific reinforcement, every individual learns many things through observation and imitation of other people.
The central process of social learning, by which a person observes the actions of others and then copies them.
An emergent theory that holds that development results from the dynamic interaction of each person with the surrounding social and cultural forces.
Zone of Proximal Development
In sociocultural theory, a metaphorical area, or zone, surrounding a learner that includes all the skills, knowledge and concepts that the person is close to acquiring but cannot yet master without help.
In sociocultural theory, a technique in which skilled mentors help novices learn not only by providing instruction but also by allowing direct, shared involvement in the activity. Also called apprenticeship in thinking.
An emergent theory of development that considers both the genetic origins of behavior (within each person and within each species) and the direct, systematic influence that environmental forces have, over time, on genes.
A general term for the traits, capacities and limitations that each individual inherits genetically from his or her parents at the moment of conception.
A general term for all the environmental influences that affect development after an individual is conceived.
The single cell formed from the fusing of 2 gametes, a sperm and an ovum.
Twins who originate from one zygote that splits apart for early in development. Also called identical twins. Triplets and Quads can occur as well.
Twins who are formed when two separate ova are fertilized by two separate sperm at roughly the same time.
A condition in which a person has 47 chromosomes instead of the usual 46, with three rather than two chromosomes at the 21st position. people with Down Syndrome typically have distinctive facial features, heart abnormalities, and language difficulties.
A person's position in society as determined by income, wealth, occupation, education, place of residence and other factors.
The first two weeks of prenatal development after conception, characterized by rapid cell division and the beginning of cell differentiation.
The stage of prenatal development from approx. the third through the 8th week after conception, during which the basic forms of all body structures, including internal organs, develop.
The stage of prenatal development from the 9th week after conception until birth, during which the organs grow in size and mature in functioning.
The organ that surrounds the developing embryo and fetus, sustaining life via the umbilical cord. The placenta is attached to the wall of the pregnant woman's uterus.
One of the billions of nerve cells in the central nervous system, especially the brain.
A fiber that extends from a neuron and receives electrochemical impulses transmitted from other neurons via their axons.
A fiber that extends from a neuron and transmits electrochemical impulses from that neuron to the dendrites of other neurons.
The intersection between the axon of one neuron and the dendrites of other neurons.
Fine Motor Skills
Physical abilities involving small body movements, especially of the hands and fingers, such as drawing and picking up a coin.
Gross Motor Skills
Physical abilities involving large body movements, such as walking and jumping.
An unlearned, involuntary action or movement emitted in response to a particular stimulus. A reflex is an automatic response that is built into the nervous system and occurs without conscious thought.
The realization that objects (including people) still exist when they can no longer be seen, touched or heard.
A sequence in which an infant first perceives something that someone else does and then performs the same action a few hours or even days later.
According to Ainsworth"an affectional tie" that an infant forms with a caregiver- a tie that binds them together in space and endures over time.
A coordinated, rapid, and smooth exchange of responses between a caregiver and an infant.
An infant's distress when a familiar caregiver leaves, most obvious between 9 and 14 months.
A relationship in which an infant obtains both comfort and confidence from the presence of his or her caregiver.
Goodness of Fit
A similarity of temperament and values that produces a smooth interaction between and individual and his or her social context, including family, school and community.
Inborn differences between one person and another in emotions, activity, and self regulation. Temperament in epigenetic, originating in genes but affected by child rearing practices.
A long, thick band of nerve fibers that connects the left and right hemispheres of the brain and allows communication between them.
A tiny brain structure that registers emotions, particularly fear and anxiety.
The process by which axons become coated with myelin, a fatty substance that speeds the transmission of nerve impulses from neuron to neuron.
Literally, sidedness, referring to the specialization in certain functions by each side of the brain, with one side dominant for each activity. The left side of the brain controls the right side of the body and vice versa.
The principle that the amount of a substance remains the same (is conserved) when its appearance changes.
Piaget's term for children's tendency to think about the world entirely from their own personal perspective.
The speedy and sometimes imprecise way in which children learn new words by tentatively placing them in mental categories according to their perceived meaning.
Pretend play in which children act out various roles and themes in stories that they create.
Rough and Tumble Play
Play that mimics aggression through wrestling, chasing or hitting, but which there is no intent to harm.
Nonphysical acts, such as insults or social rejection, aimed at harming the social connection between the victim and other people.
Unprovoked, repeated physical or verbal attack, especially on victims who are unlikely to defend themselves.
Initiative vs. Guilt
Erikson's third psychosocial crisis, in which children undertake new skills and activities and feel guilty when they do not succeed at them.
The period between early childhood and early adolescence, from approx. ages 7-11
The time it takes to respond to a stimulus, either physical (with a reflexive movement such as an eye blink) or cognitively (with a thought).
A process in which repetition of a sequence of thoughts and actions makes the sequence routine, so that is no longer requires conscious thoughts.
In an adult, having a BMI of 30 or more. In a child, having a BMI above the 95th percentile, according to the U.S. Centers for Disease Control's 1980 standards for children of a given age.
A marked delay in a particular area of learning that is not caused by an apparent physical disability, by mental retardation, or by an unusually stressful home environment.
A developmental disorder marked by an inability to relate to other people normally, extreme self absorption, and an inability to acquire normal speech.
The ability to concentrate on some stimuli while ignoring others.
Concrete Operational Thought
Piaget's term for the ability to reason logically about direct experiences and perceptions.
A body of knowledge in a particular area that makes it easier to master new information in that area.
The component of the information-processing system in which virtually limitless amounts of information can be stored indefinitely.
The component of the information processing system in which current conscious mental activity occurs.
"Thinking about thinking." or the ability to evaluate a cognitive task in order to determine how best to accomplish it, and then to monitor and adjust one's performance on that task.
The capacity to adapt well to significant adversity and to overcome serious stress.
Repeated, systematic efforts to inflict harm through physical, verbal or social attack on a weaker person.
Culture of Children
The particular habits, styles and values that reflect the set of rules and rituals that characterize children as distinct from adult society.
The ability to understand social interactions, including the causes and consequences of human behavior.
Conventional Moral Reasoning
Kohlberg's second level of moral reasoning, emphasizing social rules.
The time between the first onrush of hormones and full adult physical development. Puberty usually lasts three to five years. Many more years are required to achieve psychosocial maturity.
Primary Sex Characteristics
The parts of the body that are directly involved in reproduction, including the vagina, uterus, ovaries, testicles and penis.
Secondary Sex Characteristics
Physical traits that are not directly involved in reproduction but that indicate sexual maturity such as man's beard and a woman's breasts.
A person's idea of how his or her body looks.
An eating disorder characterized by self-starvation. Affected individuals voluntarily undereat and often overexercise, depriving their vital organs of nutrition. Anorexia can be fatal.
An eating disorder characterized by binge eating and subsequent purging, usually by induced vomiting and/or use of laxatives.
Formal Operational Thought
In Piaget's theory, the 4th and final stage of cognitive development, characterized by more systematic and logically thinking and by the ability to understand and systematically manipulate abstract concepts.
An adolescents egocentric conviction that he or she cannot be overcome or even harmed by anything that might defeat a normal mortal, such as unprotected sex, drug abuse, or high-speeding driving.
An aspect of adolescent egocentrism characterized by an adolescent's belief that his or her thoughts, feelings, and experiences are unique, more wonderful or awful than anyone else's.
The other people who, in an adolescents egocentric belief, are watching and taking note of his or her appearance, ideas and behaviors. This belief makes teens very self-conscious.
Reasoning that includes propositions and possibilities that may not affect reality.
Reasoning from a general statement, premise, or principle, through logical steps, to figure out (deduce) specifics. Also called top-down reasoning.
The logical principle that certain characteristics of an object remain the same even if other characteristics change.
A socially acceptable way for adolescents to postpone identity achievement. Going to college is a common example.
Erikson's term for premature identity formation, which occurs when an adolescent adopts parents' or society's roles and values wholesale, without questioning and analysis.
Erikson's term for the attainment of identity, or the point at which a person understands who he or she is as unique individual, in accord with past experiences and future plans.
Encouragement to conform to one's friend's or contemporaries in behavior, dress, and attitude; often a positive force, but usually considered a negative one, as when adolescent peers encourage one another to defy adult authority.
Thinking about suicide, usually when some serious emotional and intellectual or cognitive overtones.
The direction of a person's sexual and romantic attraction, whether toward others of the same sex, the opposite sex or both.
Seeking information about how to react to an unfamiliar or ambiguous object or event by observing someone else's expressions and reactions. That other person becomes a social reference.
Piaget's term for the way infant's think-by using their senses and motor skills-during the first period of cognitive development.
Piaget's term for cognitive development between the ages of about 2 and 6; it includes language and imagination (which involve symbolic thought), but logical, operational thinking is not yet possible.