Developmental psychology
The psychological specialty that studies how organisms changed over time as the result of biological and environmental influences
Nature/ nurture issue
The long-standing discussion over the relative importance of nature (heredity) and nurture (environment) in their influence on behavior and mental processes
Interaction
A process by which forces work together or influence each other - as in the interaction between the forces of heredity and environment
Identical twins
A pair who started life as a single fertilized egg, which later split into two distinct individuals. Identical twins have exactly the same genes
Fraternal twins
A pair who started life as two separate fertilized eggs that happened to share the same womb. Fraternal twins, on the average, have about 50% of their genetic material in common
Continuity view
The perspective that development is gradual and continuous - as opposed to the discontinuity (stage) view
Discontinuity view
The perspective that development proceeds in an uneven (discontinuous) fashion - as opposed to the continuity view
Developmental stages
Periods of life initiated by significant transitions or changes in physical or psychological functioning
Prenatal period
The developmental period before birth
Zygote
A fertilized egg
Embryo
In humans, the name for the developing organism during the first eight weeks after conception
Fetus
In humans, the term for the developing organism between the embryonic stage and birth
Placenta
The organ interface between the embryo or fetus and the mother. The placenta separates the bloodstreams, but it allows the exchange of nutrients and waste products.
Teratogens
Substances from the environment, including viruses, drugs, and other chemicals, that can damage the developing organism during the prenatal period
Neonatal period
In humans, the neonatal (newborn) period extends through the first month after birth
Infancy
In humans, infancy spans the time between the end of the neonatal period and the establishment of language - usually at about 18 months to 2 years
Attachment
The enduring social-emotional relationship between a child and a parent or other regular caregiver
Imprinting
A primitive form of learning in which some young animals follow and form an attachment to the first moving object they see and hear
Contact comfort
Stimulation and reassurance derived from the physical touch of a caregiver
Maturation
The process by which the genetic program manifests itself over time
Grammar
The rules of language, specifying how to use words, morphemes, and syntax to produce understandable sentences
Morphemes
The meaningful units of language that make up words. Some whole words are morphemes (example: "word"); other morphemes include grammatical components that alter a word's meaning (examples: "-ed," "-ing," and "un-").
Overregularization
applying a grammatical rule too widely and creating incorrect forms
Schemas
In Piaget's theory, mental structures or programs that guide a developing child's thought
Assimilation
A mental process that modifies new information to fit into existing schemes
Accommodation
A mental process that restructures existing schemes so that new information is better understood
Sensorimotor stage
The first stage in Piaget's theory, during which the child relies heavily on innate motor responses to stimuli
Mental representation
The ability to form internal images of objects and events
Object permanence
The knowledge that objects exist independently of one's own actions or awareness
Preoperational stage
The second stage in Piaget's theory, marked by well-developed mental representation and the use of language
Egocentrism
In Piaget's theory, the self-centered inability to realize that there are other viewpoints beside one's own
Animistic thinking
A preoperational mode of thought in which inanimate objects are imagined to have life and mental processes
Centration
A preoperational thought pattern involving the inability to take into account more than one factor at a time.
Irreversibility
The inability, in the preoperational child, to think through a series of events or mental operations and then mentally reverse the steps
Concrete operational stage
The third of Piaget's stages, when a child understands conversation but still is incapable of abstract thought
Conservation
The understanding that the physical properties of an object or substance do not change when appearances change but nothing is added or taken away
Mental operations
Solving problems by manipulating images in one's mind
Theory of mind
An awareness that other people's behavior may be influenced by beliefs, desires, and emotions that differ from one's own
Temperament
An individual's characteristic manner of behavior or reaction - assumed to have a strong genetic basis
Psychosocial stages
In Erikson's theory, the developmental stages refer to eight major challenges that appear successively across the lifespan, which require an individual to rethink his or her goals, as well as relationships with others
Adolescence
In industrial societies, a developmental period beginning at puberty and ending (less clearly) at adulthood
Puberty
The onset of sexual maturity
Primary sex characteristics
The sex organs and genitals
Secondary sex characteristics
Gender-related physical features that develop during puberty, including facial hair and deepening voice in males, widened hips and enlarged breasts in females, and the development of pubic hair in both sexes
Formal operational stage
The last of Piaget's stages, during which abstract thought appears
Generativity
In Erikson's theory, a process of making a commitment beyond oneself to family, work, society, or future generations
Selective social interaction
Choosing to restrict the number of one's social contacts to those who are the most gratifying