Study of Psychology Final PDF

GENES AND BEHAVIOR Chromosome ◦ Threadlike structures inside a cell’s nucleus that carries genes. Gene ◦ The section of a chromosome that controls the synthesis of one protein. ◦ Composed of DNA (deoxyribonucleic acid) Genome ◦ Set of all types of genes distinguished by their locus and base seque...

GENES AND BEHAVIOR Chromosome ◦ Threadlike structures inside a cell’s nucleus that carries genes. Gene ◦ The section of a chromosome that controls the synthesis of one protein. ◦ Composed of DNA (deoxyribonucleic acid) Genome ◦ Set of all types of genes distinguished by their locus and base sequence. Allele ◦ Any one of two or more genes that may occur alternatively at a given site on a chromosome. Genotype ◦ An organism’s genetic makeup. Phenotype ◦ An organism's observable traits. Dominant Gene ◦ A gene that mask’s the effect of other genes. Recessive Gene ◦ A gene that is expressed only in the absence of a dominant gene. Polygenic Transmission ◦ When a single phenotypic trait is controlled by more than one pair of genes. Epigenetics The study of heritable changes in gene function that do not involve changes in DNA sequence Knockout Procedure ◦ A technique in which a gene is made inoperative. ◦ Behaviour of KO’d animal is compared to a normal animal. ◦ More than one gene can be KO’d. ◦ Genes can also be “knocked-in” (i.e., replaced). ◦ Problems: ◦ Behaviour is often the product of multiple genes (not one) ◦ A single gene can have multiple effects Heritability : ◦ The extent to which the variation of a particular trait across individuals of a particular population is due to genes. ◦ Estimated using the heritability coefficient. ◦ E.g., 80% of the differences in height we observe in population x is due to genetics. ◦ Cannot be used to make statements about individuals. ◦ Can only be applied within a single group. Heredity : ◦ The passing of traits from parents to offspring by way of genes. Concordance : ◦ The likelihood that two people share the same characteristic. Family Studies ◦ Analysis of how characteristics run in intact families. ◦ Useful for estimating risk of a disorder among the relatives members afflicted with the disorder. ◦ Problems: ◦ Relatives share similar environment and genes (can’t separate genes and environment). Twin Studies ◦ Twins can be of two types: ◦ Identical ◦ Come from single zygote that split ( monozygotic ; MZ). ◦ Share 100% if genes. ◦ Fraternal ◦ Come from two separate zygotes ( dizygotic , DZ). ◦ Share 50% of genes. ◦ Logic: If MZ twins show more similarity on a particular trait than DZ twins, this is assumed to be reflective of genetic factors. ◦ Within both types of twins, environment is assumed to be controlled: ◦ Both types of twins grow up in the same home, at the same time, have similar neighbors, education, etc. Adoption Studies ◦ An analysis of how traits vary in individuals raised apart from their biol ◦ Adopted Person ◦ Shares genes and not environment with biological parents. ◦ Shares environment and not genes with adopted parents. ◦ Logic: ◦ If the adopted person shows a greater similarity to biological parents on a psychological assumed to be more heavily influenced by genes. ◦ If the adopted person shows a greater similarity to adopted parents on a psychological t assumed to be more heavily influenced by environment. ◦ Selective Placement Confound: ◦ Adoption agencies try and place children in homes similar to that of their biological pare ◦ Adoption studies assume that placement of the child in a home is random and not based socioeconomic or psychological status of the biological family. Reaction Range The genetically influenced limits within which environmental factors can exert their effects on an organism. Standard Deviations IQ score 55 70 85 100 115 130 145 Evolutionary Psychology ◦ A discipline that applies Darwin’s theory of Evolution by Natural Selection to human and non-human animal behaviour. ◦ Criticisms: ◦ Many claims of Evolutionary Psych are not testable and/or unfalsifiable (behaviour leaves no fossil record). ◦ Relies on many assumptions about early humans which we know very little about. ◦ Multiple “evolutionary” explanations are often possible and can conform to any finding we like