1. Are your feelings just another evolutionary adaptation?
A discussion of the field of
evolutionary psychology
In order to understand the field of evolutionary psychology we need to discuss what the field of psychology studies and what the field of evolutionary biology studies
We have to understand what an adaptation is to determine whether our feelings are adaptations

2. Psychology The study of behavior and mental function
Goal is to understand behavior
Very diverse field

3. Evolutionary Biology Studies how evolution has generated the diversity
of living organisms

4. Evolution – what is it? A change in a population over time
Before we talk about what ev psych I’d like to spend some time discussing what evolution is. This will aid in your understanding of looking at our behavior from an evolutionary perspective
Evolution is a change in a population over time
There are 4 main ways for population to evolve – however, the major way is natural selection

5. Evolution – via natural selection
The kind of evolution relevant to ev psych is natural selection

6. Peppered Moths (Biston betularia)
Pre-Industrial Revolution
Two color morphs – same species
Color has a genetic basis – genes determine color
Pre industrial England lichen covered trees, which are camouflaged better? Light ones Dark ones get eaten by bird predators more frequently
Causes dark to be found at low numbers in the population
environment (bird and lichen) are selective pressures cause light moths to be more
Mention survival of the fittest
Color is an adaptation to the environment – one color is more adaptive than another depending on enviro.
Fittest

7. Industry established
Dark Background
Different selective pressure

8. Evolution – via natural selection
What we see are physical changes in a population
Genetic changes really underlie that physical change
Evolution = change in genetic make up of a population over time
It is genetic changes that natural selection acts upon, selects for or against.
Just as we see evolution in the moths, and as we see evolution in bacteria as they become resistant to antibiotics, evolution has occurred in our own species

9. Differential retention of alternatives
Genetic differences are the source of variation in a population
These are acted upon by the process of natural selection
Natural selection selects either for or against a particular characteristic.
Favorable characteristics increase in a population over time
If selected for, characteristic will increase over time in a population
If selected against, characteristic will decline over time

10. Human Evolution Bipedalism (walking upright)
Genetic change moved foramen magnum
A genetic change (mutation) may have moved the location of the foramen magnum closer to the front
Freed up hands, foraged more efficiently, survive, reproduce pass
Arose from many small genetic changes over long periods of time
Genes mutate. Individuals are selected. Populations evolve

11. Bipedalism Freed up hands for more efficient foraging
Increased nutrients, improved reproductive success
Characteristic passed on to next generation

12. So our physical characteristics are a result of evolution through natural selection
Natural selection causes organisms to be adapted to a particular environment
What about our emotions/feelings??

13. Evolutionary Psychology
Field looks at whether our feelings/emotions are adaptations that increase our survival
Orgs that are adapted well – live long enough to reproduce and pass genes on to next generation

14. Environment of Evolutionary Adaptation (EEA)
Our behaviors are looked at in light of when they evolved
Our Environment of Evolutionary Adaptation
African Savannah, Hunter gatherer lifestyle

15. Characteristics we have today are the result of selection that occurred in the past.
Many of our behaviors or feelings may not necessarily make sense in relation to our modern lives.

16. Evolutionary Psychology
Cooperation
Kin Detection
Mate Choice
Infidelity
Emotions as adaptations – anger, jealousy, guilt

17. Jealousy Romantic jealousy
Emotional state caused by a perceived threat to a valued intimate relationship

18. Question
Imagine you discover that your partner formed a deep emotional and passionate sexual relationship with another person.
Which aspect of your partner's involvement would make you more jealous?
the deep emotional relationship? OR
the passionate sexual relationship?

19. Emotional relationship Sexual relationship
Emotional jealousy Physical jealousy
Intimacy confiding in another female
spending time with another female

21. Why the difference Difference in the size of
male and female reproductive cells (gametes)
Sperm smaller and more numerous
Eggs larger and less numerous
170 million sperm per day
I egg once per month

22. Creates different motivations
Using reproductive cells entails a different amount of parental investment
Females - lots of investment
Males less
Pregnancy, birth, nursing,
In the environment in which we evolved, males wouldn’t necessarily have to if they were around in a family group they could certainly reproduce again quickly in comparison to females

23. Females are choosy about a mate as a result
Males are less choosy

24. Human Evidence

25. What are females looking for?
Biggest and most colorful …..
Humans?? Nice car, good job
Indicate resource gathering skills
Indication of males ability to provide resources to her and offspring
Or just indication of genes that offspring will contain

26. Why are resources so important?
Ultimate goal of an organism is to have offspring and aid in survival of offspring
Passes genes into next generation
Biological Fitness = # of offspring

27. So females are choosy in order to increases fitness
Males don’t necessarily have to be choosy to increase fitness

28. Back to jealousy
Females are more likely to feel emotional jealousy because…….
Of potential redirection of resources
Jealousy an adaptive feeling kind of like a
warning alarm to indicate potential
resource redirection

29. What about males? Strategy to be less choosy
Gametes are made rapidly, low potential parental investment
SO when in a monogamous relationship have physical jealousy

30. Cuckoldry Fear of cuckoldry Raising another males offspring
Physical jealousy adaptation to reduce likelihood of cuckoldry

31. Evidence of cuckoldry in humans?
Testes size in relation to body size
Gibbons – monogamous – small
Chimpanzees – females have many partners
– large testes
Humans – somewhere in between
Size – ability to make sperm

32. Emotional jealousy Physical jealousy Potential Resource Fear of
Redirection Cuckoldry
Intimacy confiding in another female
spending time with another female
Adaptive because……

33. Summary
Human emotions (especially undesirable emotions) do appear to be adaptive
They can be seen as warning lights of a potential decline in biological fitness

34. Further Resources Online Journal – Evolutionary Psychology
Center for Evolutionary Psychology – UC Santa Barbara
David Buss - Research on jealousy
Helen Fisher – Research on romantic love and feelings associated with love

35. References
Schützwohl, A. (2004) Which Infidelity Type Makes You More Jealous? Decision Strategies in a Forced-choice Between Sexual and Emotional Infidelity. Evolutionary Psychology . 2:
Source of question
Buss, D & Schmitt, D. (1993) Sexual strategies theory: An evolutionary perspective on human mating. Psychological Review 100:
Source of graphs on male/female choosiness