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 experiences in terms of our existing schemas
accommodation
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 about 2 to 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
scaffold
a framework that offers children temporary support as they develop higher levels of thinking
autism spectrum disorder (ASD)
a disorder that appears in childhood and is marked by significant deficiencies in communication and social interaction, and by rigidly fixated interests and repetitive behaviors
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 early life
strange situation
a procedure for studying child-caregiver attachment; a child is placed in an unfamiliar environment while their caregiver leaves and then returns, and the child's reactions are observed
secure attachment
demonstrated by infants who comfortably explore environments in the presence of their caregiver, show only temporary distress when the caregiver leaves, and find comfort in the caregiver's return
insecure attachment
demonstrated by infants who display either a clinging, anxious attachment or an avoidant attachment that resists closeness
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?"
sex
biologically influenced categories by which people define male and female
gender
the socially influenced characteristics by which people define boy, girl, man, and woman
aggression
any physical or verbal behavior intended to harm someone physically or emotionally
relational aggression
an act of aggression (physical or verbal) intended to harm a person's relationship or social standing
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, attitudes, and traits for males or for females
gender identity
our sense of being male or female, or some combination of the two
social learning theory
the theory that we learn social behavior by observing and imitating and by being rewarded or punished
gender typing
the acquisition of a traditional masculine or feminine role
androgyny
displaying both traditional masculine and feminine psychological characteristics
transgender
an umbrella term describing people whose gender identity or expression differs from that associated with their birth designated sex
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
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
a period from about age 18 to the mid-twenties, when many in Western cultures are no longer adolescents but have not yet achieved full independence as adults
x chromosome
The sex chromosome found in both men and women. Females have two X chromosomes; males have one. An X 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 male sex hormone
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
spermarche
first ejaculation
menarche
the first menstrual period
intersex
a condition present at birth due to unusual combinations of male and female chromosomes, hormones, and anatomy; possessing biological sexual characteristics of both sexes
AIDS (acquired immune deficiency syndrome)
a life-threatening, sexually transmitted infection caused by the human immunodeficiency virus (HIV); depletes the immune system, leaving the person vulnerable to infections.
sexual orientation
an enduring sexual attraction toward members of either one's own sex (homosexual orientation) or the other sex (heterosexual orientation)
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
research that compares people of different ages at the same point in time
longitudinal study
research in which the same people are restudied and retested over a long period
neurocognitive disorders (NCDs)
acquired (not lifelong) disorders marked by cognitive deficits; often related to Alzheimer's disease, brain injury or disease, or substance abuse
alzheimer's disease
a neurocognitive disorder marked by neural plaques, often with an onset after age 80, and entailing a progressive decline in memory and other cognitive abilities
social clock
the culturally preferred timing of social events such as marriage, parenthood, and retirement