Biological Level Of Analysis

1. Biological Level Of Analysis How does or physiology and genetics effect our behavior?

3. Development of Biological Perspective • 370 BC….Hippocrates and his 4 Humors

4. Two things really catapulted us to think that biology effected behavior… 1848 Phineas Gage 1859 Charles Darwin wrote “On the Origin of Species” Idea that all species developed over time with the idea that “behavior is adaptive”.

5. Outline the principles that define the biological level of analysis and how they are demonstrated in research. Studies Terms Neurotransmitters Hormones Brain Evolutionary Psychology Monozygotic Twins Dizygotic Twins Concordance rate Cerebral Cortex Neuroplasticity • Phineas Gage • Bouchard et al • Rosenzweig and Bennet

6. Principles of BLA Outline the principles that define the biological level of analysisand how they are demonstrated in research • emotions and behavior are products of anatomy and physiology and endocrine systems • patterns of behavior can be inherited • animal research can help us understand behavior

7. Emotions and behavior are products of anatomy and physiology and endocrine systems Links have been found between psychological events and physiological activities in 3 main areas • The effect of neurotransmitters • The effect of hormones • The effect of brain localization

8. Research Example Phineas Gage

9. 2. Patterns of behavior can be inherited Based on work of Darwin • Genetics • Evolutionary Psychology Traits are passed on from generation to generation. Especially those that help ensure our survival.

10. Research Example Twins

11. Let’s take a better look at Twins…. • Monozygotic Twins (MZ or identical) come from the same sperm and egg and share 100% of there genes. • Dizygotic Twins (DZ or fraternal) come from two different eggs and share about 50% of their genes. • Regular siblings also share around 50% of their genes.

12. Twins In twin studies, researches focus on something called a concordance rate… • The probability that if one individual has the trait the other will also have it. • It tells us if a trait is inherited. Schizophrenia Fraternal Twins: 15% Identical Twins: 50%

13. Usually in twin studies, one twin acts as a control for the other twin. • In good twin research sets of MZ are compared to sets of DZ for a trait of disorder. • High concordance rates with MZ and lower with DZ indicates the trait is due to genes (inherited). • Differences within pairs of MZ are thought to be environmental factors.

14. Bouchard et al. (1990)Twin study investigating genetic inheritance in intelligence • This study used a self-selected sample of MZ twins who had been reared together (MZT) and MZ twins who had been reared apart (MZA). • Looked at a lot of factors but we will focus on intelligence.

15. Bouchard et al. (1990)Twin study investigating genetic inheritance in intelligence Results: • Used the WAIS to measure intelligence. • The concordance rates for MZA was 69%, for MZT it was 88%.

16. Bouchard et al. (1990)Twin study investigating genetic inheritance in intelligence • The researchers concluded that environmental factors do play a role in development of intelligence but IQ is to a large extent inherited. • 70% of the observed variation in the sample could be attributed to genetic variation.

17. Bouchard et al. (1990)Twin study investigating genetic inheritance in intelligence • They claim that in their sample (white, middle class, industrialized nation) genetic inheritance in IQ accounts for around 2/3 of observed variance of IQ. • They also said that their findings do not indicate that IQ cannot be increased by environmental factors.

18. Bouchard et al. (1990)Twin study investigating genetic inheritance in intelligence Evaluation • Correlational data cannot establish cause/effect relationships. • Concordance rates were high, but far from 100%. • No control for the effect of environmental variables. • Self-selected sample.

19. 3. Animal research may inform our understanding of behavior • Based on Darwin’s idea of evolution we share a common ancestry with animals. • So in some ways we are fundamentally the same. • Examples…..

20. Critical Periods • the optimal period shortly after birth when an organism’s exposure to certain stimuli or experiences produce proper development. Imprinting • Conrad Lorenz • The process by which certain animals form attachments during a critical period very early in life.

21. Harry Harlow and his Monkeys • Discovered that monkeys preferred the soft body contact of a cloth mother, over the nourishment of a hard/wirily mother.

22. Neuroplasticity Although localization of function does occur… • The specific location of that function is not fixed for all individuals. • It can change according to environmental demands

23. Rosenzweig and Bennett (1972)

24. Rosenzweig and Bennett (1972) Findings • Rats in the stimulating environment had an increased thickness in the cortex. • The frontal lobe (thinking, planning , decision making) was heavier in the rats that had been in the stimulating environment. • Having toys created the best conditions for developing cerebral thickness.

25. Rosenzweig and Bennett (1972) Issues • These findings can be generalized to human only to some extent. • it is difficult to decide what is considered to be anenriched environmental for a specific person. • Rats were sacrificed (Ethical)?