GENETIC INHERETENCE Can you… Describe the influence of genetic inheretence on one behavior? Opinionate (and write to) the larger issue of to what extent genetic inheretence influences our behaviors? Support both of the above questions with specific research?

PART 1: How do we study genetics??? *Twin studies Using correlational research to establish a genetic argument for the origin of human behaviour

Correlation Correlations show the relationship between two variables. There is no manipulation of an IV, so cause and effect are not established. A correlation of +1.0 means as x increases, y increases. -1.0 means that x increases, y decreases. In twin research, we expect to find a higher correlational than when comparing a child to someone outside of the family.

What is inherited? Which of the following do you think might be inherited? Why? Intelligence Depression Risk-taking behaviour Homosexuality Problem solving skills Agoraphobia

Techniques Comparing Monozygotic twins (MZ) with Dyzygotic twins (DZ). Since MZ twins have identical DNA, there should be a higher concordance rate. Comparing MZ twins reared together vs. MZ twins reared apart. Why might this be better than the first technique?

Concordance Rate Twin studies MZ Twins DZ Twins Monozygotic twins Identical Twins Share 90% of genes Dizygotic twins None-identical twins Share 50% of genes Concordance Rate

ADOPTION STUDIES Adoption studies tend to compare the adopted child with the biological mother and the adoptive mother to determine which has the higher concordance rate for a given behaviour. Why might adoption studies at times be preferrable to twin studies?

Prospective Studies Prospective studies identify traits that are considered to be inherited. Those who are considered “genetically vulnerable” are then followed over many years to see if they actually manifest the behaviour. This is used, for example, in the study of schizophrenia. There is an ethical concern in such research that it may cause undue stress and lead to iatrogenic effects in those who are labeled as vulnerable.

STRENGTHS OF TWIN STUDIES Twin studies have produced a great deal of data in support of biological roots of disorders; this has helped psychologists to stress prevention for those who are vulnerable to such disorders. There is a high cross-cultural reliability of concordance levels.

Limitations OF TWIN STUDIES MZ twins are rarely separated at birth and raised in a totally different environment, yet this is really necessary to substantiate claims. MZ twins reared together share many of the same experiences. DZ twins reared together may not share the same experiences due to levels of attractiveness or temperament.

STRENGTHS OF Adoption STUDIES Adoption studies allow researchers to isolate variables. If a biological mother has no contact since birth and still matches for a specific trait - for example, the adopted child’s IQ is better than the adoptive mother and in concordance with the birth mother - this is strong evidence that genes play a significant role in the development of this trait.

Limitations OF Adoption STUDIES Selective placement is a problem. Babies tend to placed with families similar in background to the natural parents. Adopted children – as well as twins - are not representative of all children. The act of being given up for adoption may affect the child’s behaviour.

PART 2: Intelligence and Genetics What are your definitions? How was this measured USING the IQ Test?

Intelligence How much is intelligence based on genes? Binet Gottfredson, 1994 Judgment, otherwise called "good sense," "practical sense," "initiative," the faculty of adapting one's self to circumstances ... auto-critique. A very general mental capability that, among other things, involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly and learn from experience. It is not merely book learning, a narrow academic skill, or test-taking smarts. Rather, it reflects a broader and deeper capability for comprehending our surroundings—"catching on," "making sense" of things, or "figuring out" what to do. Gardner, 1993 A human intellectual competence must entail a set of skills of problem solving — enabling the individual to resolve genuine problems or difficulties that he or she encounters and, when appropriate, to create an effective product — and must also entail the potential for finding or creating problems — and thereby laying the groundwork for the acquisition of new knowledge. It's not how smart you are, it's how you are smart.

Psychology and critical thinking: the Nature vs Nurture debate Inherited characteristics Passed on by the genes of parents Environmental influences Learned through people and situations

Limitations Lots of variables: Too many variables that come into play when comparing families. (especially when it comes to adoption and reared apart twin studies.) Researcher Bias: Researcher can choose the family to study – bias tor prove what they want not meant to favour one outcome when doing research but in this hotly debated topic they often do. Correlation vs Causation This only gives proof that genes and behaviour are correlated but doesn’t prove causation

Intelligence Bouchard and McGue (1981) Bouchard et al. (1990) Read p. 52 – 56 (Crane-pdf on Moodle) Gather information on these three studies: Bouchard and McGue (1981) Bouchard et al. (1990) Scarr and Weinberg (1977) TO DO: COMPLETE THE WORKSEET & UPLOAD TO MOODLE (This will take approximately 45 minutes)

TOPIC 3: AGRESSION AND CRIMINALITY *Adoption scenarios Child shows sign of aggression Adoptive parents don’t show any sign of aggression Biological parents show sign of aggression Child shows no sign of aggression Adoptive parents don’t show any sign of aggression Biological parents show sign of aggression Genes or environment? Genes or environment?

PEDIGREE studies Family Tree analysis Look for trends in data over multiple generations BRUNNER et al, anyone?

Vanessa George News Report One of the most high profile recent criminals in the UK. Some of you may find the information in the video upsetting.

What influences Vanessa George to be a criminal? Working in pairs discuss all the potential influences that may have had an impact Place these factors in order of influence (the largest to the least)

How much does each have an influence? What do you think? Do you agree with this?

Ishikawa & Raine (2002) Read through the handout on the 2002 study. Complete a key study sheet.

Research support Meta-analysis (1994) Coccaro et al. (1997) Mason and Frick (1994) Approximately 50% of the difference between anti-social and non-antisocial behaviour could be caused by genes Estimated that: 1. Genes accounted for more than 40% of aggression 2. Environment accounted for around 50% of physical aggression and 70% of verbal aggression