Genotype: Genetic makeup of an individual. (Never changes)
Phenotype: Observable characteristics produced by that genetic endowment. (Can be
affected by other genes)
Chromosome: A tightly coiled molecule of DNA that is partly covered by protein.
DNA contains genes. Genes code for the production of proteins.
Alleles: Alternative forms of a gene, which produces different characteristics.
Dominant Gene: The particular characteristics that it controls will be displayed.
Recessive Gene: The characteristic will not show up unless the other partner’s gene is
(Dark hair, brown eyes are dominant over blue eyes and light hair)
Polygenic transmission: Number of gene pairs combines their influences to create a
single phenotypic trait.
Recombinant DNA procedures, researchers use certain enzymes to cut the long threadlike
molecules of genetic DNA into pieces, combine them with DNA from another organism,
and insert them into a host organism.
(Used for human growth hormone)
Gene knockout: Alter a specific gene in a way that prevents it from carrying out its
normal function. Eliminates the gene.
Heritability coefficient: The extent to which variation in a particular characteristic within
a group can be attributed to genetic factors.
Adoption study: A person who was adopted in early life is compared on some
characteristic both with the biological parents, and with the adoptive parents.
Twin studies powerful technique used for genetic behavior.
1 Genetic Influences on Behavior
Reaction range: Range of possibilities, the upper and lower limits; that the genetic code
Evolution and Behavior
Biologically based mechanisms
Evolution: Change over time in frequency with which particular genes, and the
characteristics they produce, occur within an interbreeding population.
Genetic variation arises through mutations, which makes evolution possible
Natural Selection: Characteristics that increase the likelihood of survival and ability to
reproduce within a particular environment will be more likely to be preserved in the
population and therefore will become more common in the species overtime.
Adaptations: (Product of natural selection) Allows organisms to meet recurring
environmental challenges to their survival, therefore increasing their reproductive ability.
Domain-specific adaptations: Designed to solve a particular problem, such as selecting a
suitable mate, choosing safe foods to eat, etc. …
Human mind isn’t general; meant to handle specific adaptive problems.
Evolutionary personality theory: Limited number of basic dimensions.
Parental investment: The time, effort, energy, and risk associated with caring successfully
for each offspring.
Polygyny: One male may mate with many females.
Polyandry: One female may mate with many males.
Polygynandry: All members of the group mate with all other members of the group.
Cross-culturally, women tend to prefer males who show signs of willingness to invest in
children and physical health, ambitiousness, potential…
Male preferences include physical attractiveness, good health, and young age.
Monogamous mating system: Equal, or approximately equal, parental investment is
2 Species help each other 2 broad categories of helping:
- Cooperation: Situations in which one individual helps another and in so doing also
gains some advantage.
- Altruism: When one individual helps another, but in so doing he or she accrues
o Kin Selection Theory: Argues that altruism is developed to increase the survival
o Theory of reciprocal altruism: Argues that altruism is, in essence, long-term
cooperation. One individual may help another, but that action will be
reciprocated in the future. (Remember who has helped you; and help them
also)(No assistance to those who have failed to reciprocate)
How not to think about behavior genetics and evolutionary psychology
All behaviors are a function of a person’s biology and environment. We can regulate our
own behavior and exercise moral control (just as important to our survival)
Genes and environment affect each other over time.
Fallacies of evolutionary behavior:
- Genetic determinism: The idea that genes have invariant and unavoidable effects
that cannot be altered; the idea that genes are destiny.
- Social Darwinism: The notion of genetic superiority of those at the top of the social
hierarchy. (Destructive consequences Nazi)
- Evolution has a plan: (No plan, there is only adaptation to environmental demands
and the natural selection process that results.
3 Chapter 5
Synesthesia: “Mixing of the sense”
Sensation is the stimulus-detection process by which our sense organs respond to and
translate environmental stimuli into nerve impulses that are sent to the brain.
Perception: Making “sense” of what our senses tell us the active process of organizing
the stimulus input and giving it meaning.
Transduction is the process whereby the characteristics of a stimulus are converted into
Psychophysics: Studies relations between the physical characteristics of stimuli and
Absolute threshold: (Stimulus detection) The lowest intensity at which a stimulus can be
detected correctly 50% of the time. (The lower the absolute, the greater the sensitivity)
Decision criterion: (No exact threshold) Standard of how certain they must be that a
stimulus is present before they will they say they detect it. (Can change due to fatigue,
etc. … )
Signal detection theory: Concerned with factors that influence sensory judgments.
Difference threshold: Defined as the smallest difference between two stimuli that people
can perceive 50% of the time.
Weber’s Law states that the difference threshold is directly proportional to the magnitude
of the stimulus with which the comparison is being made.
4 The Sensory Systems: Vision
- Light waves enter the eye through the cornea.
(Transparent protective structure at the front of the eye)
- Behind the cornea is the pupil,
(Adjustable opening that