Developmental psychology

• The branch of psychology that studies how people change over the lifespan

Chromosome

• A long, threadlike structure composed of twisted parallel strands of DNA; found in the nucleus of the cell

Gene

• The basic unit of heredity that directs the development of a particular characteristic; the individual unit of DNA instructions on a chromosome

Deoxyribonucleic acid (DNA)

• The chemical basis of heredity; carries the genetic instructions in the cell

Genotype

• The underlying genetic makeup of a particular organism, including the genetic instructions for traits that are not actually displayed

Phenotype

• The observable traits or characteristics of an organism as determined by the interaction of genetics and environmental factors

Dominant gene

• In a pair of genes, the gene containing genetic instructions that will be expressed whether paired with another dominant gene or with a recessive gene

Recessive gene

• In a pair of genes, the gene containing genetic instructions that will not be expressed unless pair with another recessive gene

Sex chromosomes

• Chromosomes designated as X or Y that determine biological sex; the 23rd pair of chromosomes in humans

Sex-linked recessive characteristics

• Traits determined by recessive genes located on the X chromosome; in males, these characteristics require only one recessive gene to be expressed

Prenatal stage

• The stage of development before birth; divided into the germinal, embryonic, and fetal periods

Germinal period

• The first two weeks of prenatal development

Embryonic period

• The second period of prenatal development, extending from the third week through the eighth week

Teratogens

• Harmful agents or substances that can cause malformations or defects in an embryo or fetus

Fetal period

• The third and longest period of prenatal development, extending from the ninth week until birth

Temperament

• Inborn predispositions to consistently behave and react in a certain way

Attachment

• The emotional bond that forms between an infant and caregiver(s), especially his or her parents

Comprehension vocabulary

• The words that are understood by an infant or child

Production vocabulary

• The words that an infant or child understands and can speak

Sensorimotor stage

• In Piaget’s theory, the first stage of cognitive development, from birth to about age 2; the period during which the infant explores the environment and acquires knowledge through sensing and manipulating objects

Object permanence

• The understanding that an object continues to exist even when it can no longer be seen

Preoperational stage

• In Piaget’s theory, the second stage of cognitive development, which lasts from about age 2 to age 7; characterized by increasing use of symbols and prelogical thought process

Symbolic thought

• The ability to use words, images, and symbols to represent the world

Egocentrism

• In Piaget’s theory, the inability to take another person’s perspective or point of view

Irreversibility

• In Piaget’s theory,the inability to mentally reverse a sequence of events or logical operations

Centration

• In Piaget’s theory, the tendency to focus,or center , on only once aspect of a situation and ignore other important aspects of the situation

Conservation

• In Piaget’s theory, the understanding that two equal quantities remain equal even though the form or appearance is rearranged, as long as nothing is added or subtracted

Concrete operational stage

• In Piaget’s theory, the third stage of cognitive development, which lasts from about age 7 to adolescence; characterized by the ability to think logically about concrete objects and situations

Formal operational

• In Piaget’s theory, the fourth stage of cognitive development, which lasts from adolescence through adulthood; characterized by the ability to think logically about abstract principles and hypothetical situations

Information-processing model of cognitive development

• The model that views cognitive development as a process that is continuous over the lifespan and that studies the development of basic mental processes such as attention, memory, and problem solving

Adolescence

• The transitional stage between late childhood and the beginning of adulthood, during which sexual maturity is reached

Identity

• A person’s definition or description of himself or herself, including the values, beliefs, and ideals that guide the individual’s behavior

Moral reasoning

• The aspect of cognitive development that has to do with how an individual reasons about moral decisions

Menopause

• The natural cessation of menstruation and the end of reproductive capacity in women

Activity theory of aging

• The psychosocial theory that life satisfaction in late adulthood is highest when people maintain the level of activity the displayed earlier in life

Authoritarian parenting style

• Parenting style in which parents are demanding and unresponsive toward their children’s needs or wishes

Permissive parenting style

• Parenting style in which parents are extremely tolerant and not demanding; permissive-indulgent parents are responsive to their children, whereas permissive indifferent parents are not

Authoritative parenting style

• Parenting style in which parents set clear standards for their children’s behavior but are also responsive to their children’s needs and wishes

Induction

• A discipline technique that combines parental control with explaining why a behavior is prohibited

Mary D. Salter Ainsworth (1913-1999)

American psychologist who devised the Strange Situation procedure to measure attachment; contributed to attachment theory

Renee Baillargeon (b. 1954)

Canadian-born psychologist whose studies of cognitive development during infancy using visual rather than manual tasks challenged beliefs about the age at which object permanence first appears

Noam Chomsky (b. 1928)

American linguist who proposed that people have an innate understanding of the basic principles of language, which he called a “universal grammar.”

Erik Erikson (1902-1994)

German-born American psychoanalyst who proposed an influential theory of psychological development throughout the lifespan

Lawrence Kohlberg (1927-1987)

American psychologist who proposed an influential theory of moral development

Jean Piaget (1896-1980)

Swiss child psychologist whose influential theory proposed that children progress through distinct stages of cognitive development

Lev Vygotsky (1896-1934)

Russian psychologist who stressed the importance of social and cultural influences in cognitive development