Developmental Psychology
a branch of psychology that studies physical, cognitive, and social change throughout the life span.
Zygote
the fertilized egg; it enters a 2-week period of rapid cell division and develops into an embryo.
Embryo
the developing human organism from about 2 weeks after fertilization through the second month.
Fetus
the developing human organism from 9 weeks after conception to birth.
Teratogens
agents, such as chemicals and viruses, that can reach the embryo or fetus during prenatal development and cause harm.
Fetal Alcohol Syndrome (FAS)
physical and cognitive abnormalities in children caused by a pregnant woman's heavy drinking. In severe cases, symptoms include noticeable facial misproportions.
Habituation
decreasing responsiveness with repeated stimulation. As infants gain familiarity with repeated exposure to a visual stimulus, their interest wanes and they look away sooner.
Maturation
biological growth processes that enable orderly changes in behavior, relatively uninfluenced by experience.
Cognition
all the mental activities associated with thinking, knowing, remembering, and communicating.
Schema
a concept or framework that organizes and interprets information.
Assimilation
interpreting our new experience in terms of our existing schemas.
Accommodation
Development - adapting our current understandings (schemas) to incorporate new information.
Sensorimotor Stage
in Piaget's theory, the stage (from birth to about 2 years of age) during which infants know the world mostly in terms of their sensory impressions and motor activities.
Object Permanence
the awareness that things continue to exist even when not perceived.
Preoperational Stage
in Piaget's theory, the stage (from 2 to about 6 or 7 years of age) during which a child learns to use language but does not yet comprehend the mental operations of concrete logic.
Conservation
the principle (which Piaget believed to be a part of concrete operational reasoning) that properties such as mass, volume, and number remain the same despite changes in the forms of objects.
Egocentrism
in Piaget's theory, the preoperational child's difficulty taking another's point of view.
Theory of Mind
people's ideas about their own and others' mental states�about their feelings, perceptions, and thoughts, and the behaviors these might predict.
Concrete Operational Stage
in Piaget's theory, the stage of cognitive development (from about 6 or 7 to 11 years of age) during which children gain the mental operations that enable them to think logically about concrete events.
Formal Operational Stage
in Piaget's theory, the stage of cognitive development (normally beginning about age 12) during which people begin to think logically about abstract concepts.
Autism
a disorder that appears in childhood and is marked by deficient communication, social interaction, and understanding of others' states of mind.
Stranger Anxiety
the fear of strangers that infants commonly display, beginning by about 8 months of age.
Attachment
an emotional tie with another person; shown in young children by their seeking closeness to the caregiver and showing distress on separation.
Critical Period
an optimal period shortly after birth when an organism's exposure to certain stimuli or experiences produces proper development.
Imprinting
the process by which certain animals form attachments during a critical period very early in life.
Temperament
a person's characteristic emotional reactivity and intensity.
Basic Trust
according to Erik Erikson, a sense that the world is predictable and trustworthy; said to be formed during infancy by appropriate experiences with responsive caregivers.
Self-Concept
all our thoughts and feelings about ourselves, in answer to the question, "Who am I?
Gender
in psychology, the biologically and socially influenced characteristics by which people define male and female.
Aggression
physical or verbal behavior intended to hurt someone.
X Chromosome
the sex chromosome found in both men and women. Females have two of these; males have one. One chromosome from each parent produces a female child.
Y Chromosome
the sex chromosome found only in males. When paired with an X chromosome from the mother, it produces a male child.
Testosterone
the most important of the male sex hormones. Both males and females have it, but the additional levels in males stimulates the growth of the male sex organs in the fetus and the development of the male sex characteristics during puberty.
Role
a set of expectations (norms) about a social position, defining how those in the position ought to behave.
Gender Role
a set of expected behaviors for males or for females.
Gender Identity
our sense of being male or female.
Gender Typing
the acquisition of a traditional masculine or feminine role.
Social Learning Theory
the theory that we learn social behavior by observing and imitating and by being rewarded or punished.
Adolescence
the transition period from childhood to adulthood, extending from puberty to independence.
Puberty
the period of sexual maturation, during which a person becomes capable of reproducing.
Primary Sex Characteristics
the body structures (ovaries, testes, and external genitalia) that make sexual reproduction possible.
Secondary Sex Characteristics
nonreproductive sexual characteristics, such as female breasts and hips, male voice quality, and body hair.
Menarche
the first menstrual period.
Identity
our sense of self; according to Erikson, the adolescent's task is to solidify a sense of self by testing and integrating various roles.
Social Identity
the "we" aspect of our self-concept; the part of our answer to "Who am I?" that comes from our group memberships.
Intimacy
in Erikson's theory, the ability to form close, loving relationships; a primary developmental task in late adolescence and early adulthood.
Emerging Adulthood
for some people in modern cultures, a period from the late teens to mid-twenties, bridging the gap between adolescent dependence and full independence and responsible adulthood.
Menopause
the time of natural cessation of menstruation; also refers to the biological changes a woman experiences as her ability to reproduce declines.
Cross-Sectional Study
a study in which people of different ages are compared with one another.
Longitudinal Study
research in which the same people are restudied and retested over a long period.
Crystallized Intelligence
our accumulated knowledge and verbal skills; tends to increase with age.
Fluid Intelligence
our ability to reason speedily and abstractly; tends to decrease during late adulthood.
Social Clock
the culturally preferred timing of social events such as marriage, parenthood, and retirement.