1. GENETICS AND BEHAVIOUR
IB Psychology LAJM

2. What are genes?
Long molecules of DNA (deoxyribonucleic acid) that exist in chromosome structures in every cell nucleus

3. What are genes?
Genes code and regulate the production of protein molecules
Structural proteins
Enzymes
Structural proteins form the structure every cell in the body. Enzymes control the chemical reactions in every cell. Basically, genes make us what we are.

4. What are genes?
Genome is the entirety of individual’s genetic information
The human genome contains 23 pairs of chromosomes

5. What are genes?
Not all genes that individual possesses are expressed at the same time
Genes can be switched on and off

6. Remember the interactionist approach!
Genes and behaviour
Genes are entwined with the environment and behaviour
Influences what genes are switched on and off
Genes do not function in void, genes are always expressed in context. Hormones affect the expression of genes from the inside of the body and environmental events from the outside. Interactionist approach: biology and environment influence each other reciprocally.
Remember the interactionist approach!

7. Genes and behaviour
Epigenetics refers to changes in gene functions that do not change the actual DNA structure
Watch the following video on epigenetics:

8. Genes and behaviour
Genotype refers to set of genes an individual inherits
Phenotype refers to observable properties of the body and behavioural traits

9. Genetic similarities Genetic similarity refers to relatedness
Heredity means passing on traits from parents to offspring
The greater the genetic similarities between two individuals or a group of individuals the higher the degree of relatedness. Inherited traits tend to be similar

10. Genetic similarities
Genetic research in humans is largely based on correlational studies on twins, families and adoption
The question is: how much do genes effect our behaviour?

11. TASK
Read Crane 52–53
Find out the basics of twin, family and adoption studies

12. TASK Watch the following video on twin studies

13. TASK
Read Crane 53–56
Find out how the heritability of intelligence has been studied

14. Genetic explanation of behaviour
Evolution is the process where genes that are better for survival and reproduction become more common within a population
Those who adapt best to the environment have the best chances of survival and reproduction. This is natural selection. The environment challenge each individual. Evolution pressures individuals to behave in a manner that improves their chances to survive and reproduce.

15. TASK Watch the following video on evolution Pick the following terms:
Pick the following terms:
Recombination
Mutation
Selection

16. Genetic explanation of behaviour
Adaptation is an inherited characteristic that increases individual’s chances for survival and reproduction
Adaptation is a process where species develop characteristics that make it more competitive in its environment. Evolution is a long term adaptation process.

17. Genetic explanation of behaviour
Evolutionary psychology attempts to explain human behaviour based on the development of our species over time
Basically, all the psychological characteristics that have served our ability survive and reproduce are in the centre of evolutionary psychology. Natural selection cannot select for a behaviour; it can only select for mechanisms that produce behaviour. If genes code for behaviour as well as physical traits, then behaviour is subject to evolutionary pressures in the same way that physical traits are subject to evolutionary pressures.

18. Genetic explanation of behaviour
Darwing noted that humans communicat certain emotional expressions like other animals. Blind people smile, although they have never seen anyone smiling.

19. Genetic explanation of behaviour
Six basic emotional expressions are universal in all human cultures
(Darwin 1872/1965; Ekman & Friesen 1975, 1982)

20. Genetic explanation of behaviour
Eyebrow flash is a universal sign of greeting among friends
. (Eibl-Eibesfield, 1989)

21. Genetic explanation of behaviour
We are biologically predisposed to express certain emotions in species-typical way
This characteristic has served our ability survive and reproduce. This doesn’t mean that ALL emotional expressions are universal. Cultures differ in when, how and to whom basic emotions are allowed to be expressed. In addition, culture-specific emotions exist.

22. TASK
Read Crane 58–59
Find out how disgust has been studied from the perspective of evolutionary psychology
(Fessler, 2006; Curtis et al., 2004)

23. Genetic explanation of behaviour
Monogamy: equal male and female parental investment. Polygyny: high female, low male parental investment. Polyandry: High male, low female parental investment. Promiscuity: investment in group => harmony within the group.

24. Genetic explanation of behaviour
Human children require extended period of care
Rearing offspring require near equal parental investment
Humans are primarily monogamous, but moderately polygynous
This characteristic has served our ability survive and reproduce

25. Genetic explanation of behaviour
Emotions of romantic love and sexual jealousy are found in every culture
Help to develop and preserve strong emotional ties between couples
This characteristic has served our ability survive and reproduce + take care of our offspring

26. Genetic explanation of behaviour
Lust can motivate to engage in sex outside bonds
Male motives
Spread more copies of his genes
Female motives
Increase chances of conception
Increase evolutionary fitness
Provisions more than one man
This characteristic has served our ability survive and reproduce

27. TASK What are the pros and the cons of evolutionary psychology?
Try to integrate some TOK as well into your thoughts

28. Sources
Bjorklund, D. & Gray, P. (2014). Psychology (7th edition). New York: Worth Publishers.
Crane, J. & Hannibal, J. (2009). Psychology Course Companion. Oxford: Oxford University Press.

29. Picture sources
Chromoseme-DNA < Accessed 10th of November 2017.
Rotating DNA < Accessed 10th of November 2017.
Human chromosomes < Accessed 10th of November 2017.
Human gene < Accessed 26th of August 2017.
Genes, environment and behaviour. Björklund & Gray, 2014, page 59.
Gene, environment and phenotype < Accessed 10th of November 2017.
Heredity < Accessed 10th of November 2017.
Twins < Accessed 11th of November 2015.
Types of twins < Accessed 10th of November 2017.
Nancy Segal < Accessed 10th of November 2017.
Wheel head < Accessed 10th of November 2017.
Charles Darwin < Accessed 10th of November 2017.

30. Picture sources
Evolution < Accessed 10th of November 2017.
Adaptation < Accessed 10th of November 2017.
Evolutionary psychology < Accessed 10th of November 2017.
The expression of the emotions in man and animals < Accessed 10th of November 2017.
Blind child smiling < Accessed 10th of November 2017.
Six basic emotions < Accessed 10th of November 2017.
Eyebrow flash < Accessed 10th of November 2017.
Six basic emotions 2 < Accessed 23rd of October 2017.
Disgust < Accessed 10th of October 2017.
Mating systems < Accessed 10th of November 2017.
Child learning to walk < Accessed 10th of November 2017.
Jealousy < Accessed 10th of November 2017.
Lust < Accessed 10th of November 2017.
Evolution cartoon < Accessed 10th of November 2017.