An Evolutionary E xplanation of Emotion

1. An Evolutionary Explanation of Emotion By Mr Daniel Hansson

2. Questions • If you had three cows, but only enough to keep two of them alive, which one would you slaughter? • Why don’t we marry our sisters or brothers? • Why are apples sweet? Why do you think children like sweets? • Consider the following quote. What does it mean? “We have stone age genes and minds forced to live in a space age culture.”

3. Darwin • Went on a round-the-world journey with “The beagle” 1831 • Author of Origin of species (1859) and Descent of Man (1871)

4. Influence of Darwin • On Galapagos, Darwin noticed that the beaks of finches differed depending on the islands • The beaks were highly adapted to the food source on the island

5. Darwin’s Theory of Evolution 1. Evolution: Life on earth has evolved (developed gradually) over millions of years from a few common ancestors 2. Heredity: Offspring inherits the traits of their parents 3. Natural selection: Competition of resources must inevitably arise between organisms. Traits which enhance adaptation and thereby survival and reproduction rates, are the most likely to be transmitted over generations.

6. Darwin’s Theory of Evolution 4. Speciation: Development of different species occurs because the more adaptive species in an environment overcomes competitors. 5. Variation: Even if more adaptive traits are most common, there is a variation of traits in a population of a species. This enables the species to adapt to sudden environmental changes.

7. Fitness • An organism’s ability to survive depends on how well its characteristics allow it to: • Exploit the opportunities available in its environment • Avoid or deal with the threats presented by its environment • We call this the organism’s fitness www.psychlotron.org.uk

8. Fitness www.psychlotron.org.uk

9. Fitness Yummy! www.psychlotron.org.uk

10. Arse. Arse. Arse. Fitness www.psychlotron.org.uk

11. Fitness • Fit organisms are more likely to survive into adulthood than unfit ones. • Consequently, they are more likely to mate and have offspring • They pass on their genes to the next generation • Gradually, the genes for successful characteristics spread through the population www.psychlotron.org.uk

12. Fitness • Fitness is all about how well an organism is adapted to its environment • The environment changes over time – sometimes gradually, sometimes rapidly • So a characteristic/gene that is adaptive at one time may become maladaptive if the environment changes www.psychlotron.org.uk

13. Challenging Evolution • If the purpose of all life is to reproduce, why aren’t there more men donating sperm? • If traits that enhance reproduction are more likely to survive, why is there homosexuality?

14. Answers by Evolutionary Psychologists • The genetic drive to reproduce is an unconscious urge that nature expresses by fixed behavioural patterns, e.g. sexuality. • Homosexual individuals can still have children. The gene related to homosexuality may increase fertility in women.

15. An Evolutionary Explanation of Emotion • Motivates behaviour (e.g. to avoid danger) • Aids communication within a group

16. Supporting Study 1 • Ekman (1973) interviewed and tested participants from 22 countries, including the South Fore people in Papua Guinea, who have had no prior contact to western culture • People with different cultural background chose the same facial expression for their emotions • The conclusion is that our basic emotional life may be innate and has been formed by natural selection

18. Supporting Study 2: Fear • Disposes us to avoid what may harm us • Arouses the body, make it more apt to flee the threat • Freezing may help concealment from a predator • By submission you can avoid aggression from a stronger opponent

19. Empirical Support: Disposition for Fear • Buss (1999): Even though electricity and cars are more dangerous to us, we are more likely to fear snakes, heights, confided spaces, strangers and unfamiliar settings • Mineka (1987): It is easier for infant Rhesus monkeys to learn to fear toy snakes than to learn to fear flowers • Mineka (1989): Participants are more likely to associate pain with snakes and spiders than flowers or mushrooms (problem: spiders have never posed a major threat to humans)

20. Evolution of phobias

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27. Disgust • Disgust helps us to avoid bad food in order to minimize disease and infection

28. Empirical support: Innate Disgust • Fessler (2006): Women in the first trimester of their pregnancy are more sensitive to disgusting scenarios involving food • Curtis (2004): Disgust reactions are most strongly elicited for those which threaten one’s immune system and decreases with age

29. Sadness • Sadness triggered by failure or loss may discourage the behaviour that led to them • To signal need and to elicit help from others (Cutili et al., 2010)

30. Evaluation of theory: Strengths • Can provide insights into our psychology • Empirical support • Universality: Similar behaviors have been observed across cultures (e.g. Ekman 1973)

31. Evaluation: Limitations • Animal studies: Problems with generalising to humans • Use of correlation studies: Cannot infer cause-effect • Because little is known of early humans, statements of how humans used to be is hypothetical

32. Evaluation of theory: Limitations • Underestimation of cognitive and socio cultural influences on behavior (e.g. cultural and gender schemas, social learning) • Not all biological traits are adaptations – some are just side-effects or by-products of adaptations (Gould, e.g. writing ability)