Is it all in the GENES?

Discussion – Pair and Share  What is a personality characteristic, talent, or skill that runs in your family?  Who in your family has it?  Make a little family tree chart depicting it  What is the likelihood that the trait is genetically influenced? Why do you say so?  What is the likelihood that the environment has more to do with the trait being in the family?

What is heritability?  Review…  An estimate of the proportion of the total variance in some trait that is attributable to genetic differences among individuals within a group.  In other words…when looking at a group, how much of a certain trait is genetic (vs. environmental)?  Key points:  1. Only applies to a group living in the same environment  2. DOES NOT apply to individuals, only to variations within a group  3. Even highly heritable traits can be modified by the environment

How do we test heritability?  Twin Studies  Why?  Why identical vs. fraternal? What would each show us?  F79LY F79LY  Adoption Studies?  Why?

Is your I.Q. genetic?  Intelligence Quotient  For many years calculated as:  Mental age/chron. Age X 100.  Is this a good way?  What about other ways of showing intelligence?  Biases?  Twin studies results:  Identical twins scores correlated more than fraternal  Adoption Studies:  Children correlated more with biological parents than adopted parents.

I.Q. tests as a way to further RACISM  HH Goddard’s tests on immigrants (middle 105)  The Bell Curve  Remember Phrenology?  Eugenics  applied science or the bio-social movement which advocates the use of practices aimed at improving the genetic composition of a population  Reading from “Race” is a Four-Letter Word: the Genesis of the Concept

Flaws in Heritability Estimates  Most groups compared to mainly white samples.  People as Tomato Plant metaphor:  (pg 107!)

Genes and Personality  Heredity and Temperament  Temperament = how we typically respond to our environment  Jerome Kagan did research on infant temperaments and how that would affect people later in life  20% all babies highly reactive (excitable/nervous)  20% all babies highly NONreactive (laidback/curious)  Other 60% are somewhere in between  Reactive children…mild stressors caused more action in the sympathetic nervous system, more norepinephrine (adrenaline) and cortisol (increases blood sugar)

Heredity and Personality Traits  Trait  habitual way of thinking, behaving, and feeling  Raymond B. Cattell’s Factor Analysis studies supported the idea of the BIG 5  1. Introversion vs. Extroversion  2. Neuroticism/ negative emotionality  3. Agreeableness  4. Conscientiousness  5. Openness to experience

Final Thoughts  If many studies show a.5 correlation between a trait and genetic inheritance, that means the other.5 of our make-up is influenced by our environment.  Some studies my underestimate the impact of the environment  Even traits that are highly heritable are not rigidly fixed and can be modified by experience.

 “The wave of acceptance of genetic influence on behavior is growing into a tidal wave that threatens to engulf the second message of this research: These same data provide the best available evidence for the importance of environmental influences” (Plomin, 1989).

Discussion Questions:  ***Get into your Group Trip to the Australian Outback***  1. Just because a behavior is universal doesn’t mean that there is necessarily a genetic basis for the behavior. Geneticist Richard Lewontin point out that if 99% of Finnish are Lutheran, it doesn’t mean that Finns have a gene for Lutheranism. What other behaviors are universal (or almost universal), but are unlikely to be genetically determined?

 2. Suppose that scientists developed a genetic test that would tell prospective parents whether they were carriers of a gene that contributes to obesity. Should this test be routinely offered to couples? What about a test that could predict lower than average intelligence? More generally, what are the consequences to individuals and to society of genetic engineering?

 3. Evolutionary theory argues that variability is important for the ultimate survival of a species. But some would use genetic engineering to reduce variability and eliminate undesirable characteristics. What might be the possible problems with this approach? Can you imagine a scenario in which a genetic “flaw” resulting in obesity, for example, might be adaptive?

 4. If a gene is found for a predisposition to antisocial behavior, should this finding change the way we deal with criminals? If so, how?