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
accommodation
adapting our current understandings (schemas) to incorporate new information
assimilation
interpreting our new experiences in terms of our existing schemas
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
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
egocentrism
in Piaget's theory, the preoperational child's difficulty taking another's point of view
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
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
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
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
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
schema
a concept or framework that organizes and interprets information
stranger anxiety
the fear of strangers that infants commonly display, beginning by about 8 months of age
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.
teratogens
(literally, "monster maker") agents, such as chemicals and viruses, that can reach the embryo or fetus during prenatal development and cause harm
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