| Term | Definition |
| nativists | psychologists that emphasized the genetic and "natural" characteristics |
| empiricists | psychologists that emphasized learning and experience or "nurture" |
| evolutionary psychology | A field of psychology emphasizing evolutionary mechanisms that may help explain human commonalities in cognition, development, emotion, social practices, and other areas of behavior. |
| behavioral genetics | An interdisciplinary field of study concerned with the genetic bases of individual differences in behavior and personality |
| genes | The functional units of heredity; they are composed of DNA and specify the structure of proteins. |
| chromosomes | Within every cell, rod-shaped structures that carry the genes. |
| DNA | The chromosomal molecule that transfers genetic characteristics by way of coded instructions for the structure of proteins. |
| noncoding DNA | DNA that lies outside the genes. |
| genome | The full set of genes in each cell of an organism (with the exception of sperm and egg cells), together with noncoding DNA located outside the genes. |
| linkage studies | take advantage if the tendency if genes lying close together on a chromosome to be inherited together across generations. |
| genetic markers | A segment of DNA that varies among individuals, has a known location on a chromosome, and can function as a genetic landmark for a gene involved in a physical or mental condition. |
| evolution | A change in gene frequencies within a population over many generations; a mechanism by which genetically influences characteristic of a population may change. |
| mutate | When an error occurs in the copying of original DNA sequence, genes can spontaneously change. |
| natural selection | The evolutionary process in which individuals with genetically influences traits that are adaptive in a particular environment tend to survive and to reproduce in greater numbers that do other individuals; as a result, their traits become more common. |
| mental modules | Independent mental modules to handle specific survival problems. |
| language | A system that combines meaningless elements such as sounds or gesture to form structured utterances that convey meaning. |
| surface structure | the way the sentence is actually spoken or signed (in language) |
| deep structure | how a sentence is to be understood. |
| syntax | the rules of grammar |
| universal grammar | a theory that everyone is sensitive to the core features common to all languages. |
| overregularizations | When a child has learned the syntax, but is naive to other things "goed" "taked me to the store" |
| computer neural networks | Mathematical models of the brain that "learn" by adjusting the connections among hypothetical neurons in response to incoming data. |
| sociobiology | An interdisciplinary field that emphasizes evolutionary explanations of social behavior in animals, including human beings. |
| heritability | A statistical estimate of the proportion of the total variance in some trait that is attributable to genetic difference among individuals within a group. |
| identical (monozygotic) twins | Twins that develop when a fertilized egg divides into two part that develop into separate embryos. |
| fraternal (dizygotic) twins | Twins that develop from two separate eggs fertilized by different sperm; they are no more alike genetically that are any other pair of siblings. |
| intelligence quotient (IQ) | A measure of intelligence originally computed by dividing a person's mental age by his or her chronological age and multiplying the result by 100; it is now derived from norms provided for standardized intelligence tests. |
| epigenetics | The study of changes in gene expression dues to mechanisms other than structural changes in DNA. |
