1. Introduction to Psychology Suzy Scherf Lecture 2: How Did We Get Here? Critiquing the SSSM Evolution, Heredity, and Behavior

2. What is Psychology Like w/o Evolution? 1. 2. 3. 4. 5.

3. 6. It presumes that learning operates by a very small number of general-purpose mechanisms. What is Psychology Like w/o Evolution?

4. Some things we are overprepared to learn Other things we are underprepared to learn 6. It presumes that learning operates by a very small number of general-purpose mechanisms. What is Psychology Like w/o Evolution?

5. 7. It underestimates the biological constraints on behavior. What is Psychology Like w/o Evolution?

6. Universal People – Donald Brown (1991) Universal Characteristics: 7. It underestimates the biological constraints on behavior. What is Psychology Like w/o Evolution?

7. 8. It assumes that the psychologists’ job is to discover how culture and experience produce variation in human behavior. What is Psychology Like w/o Evolution?

8. Psychology with Evolution 1. It has a basic understanding of what the mind is for.

9. 2. Psychologists can ask questions about why the mind exists in terms of its designed function Psychology with Evolution

10. 3. Research findings across sub-disciplines make more sense Psychology with Evolution

11. Debunking Myths about Evolution 1. Evolution doesn’t make sense because there is no fossil record that shows how humans came from chimps! Myth: Truth:

12. Myth: GREAT CHAIN OF BEING Angels Humans Apes Plants GOD Rocks Lowest complexity Highest complexity Debunking Myths about Evolution

13. Truth: Beginning Today ChimpsMonkeys Clams E. Coli Twigs = Extinct Species Humans Cousins Debunking Myths about Evolution

14. Truth: Debunking Myths about Evolution

15. 2. Humans are the ultimate goal of evolution. Myth: Debunking Myths about Evolution Truth:

16. Who thinks we are “higher” than a virus? Debunking Myths about Evolution

17. 3. Step-children are more likely to be abused, so it must be “natural.” Myth: Truth: Debunking Myths about Evolution

18. 3. Naturalistic Fallacy Debunking Myths about Evolution Herbert Spencer - Social Darwinism “The poverty of the incapable, the distresses that come upon the imprudent, the starvation of the idle, and those shoulderings aside of the weak by the strong…are the decrees of a large, farseeing benevolence.”

19. The Theory of Evolution What does the theory explain? How does evolution influence change in biological organisms?

20. What does the Theory of Evolution Explain?

22. 1. 2.

23. Evolution via Natural Selection How does it Work?

24. What is Natural Selection? Natural Selection is a filter that weeds out those who get to pass on their traits from those that don’t. Eventually, traits that get passed down become more common and individuals are better able to deal with current environmental challenges.

25. Environmental Barriers to Reproduction And Survival Natural Selection - Filter Analogy Individuals in Current Generation

26. Natural Selection is Survival of the Fittest, Right?

27. Natural Selection is Survival of the Fittest, Right?

28. Natural Selection is... Frigate BirdGalapagos Penguins Beach lizards

29. Evolution via Natural Selection Selection can only choose from existing alternatives Evolution is cumulative - Traits spread b/c they yield a net profit in reproductive success

30. What does Natural Selection Produce?

31. What are Adaptations? Natural Selection is always designing organisms for the sole purpose of reproduction. Adaptations are

32. What are Adaptations? Natural Selection can design any traits that contribute to reproduction. Including:

33. How do We Recognize Adaptations? 1. Structural complexity (many parts) - 2. Designed for a particular function - 3. Specialized for a narrow function -

34. Types of Adaptations Obligate adaptations - Including:

35. Types of Adaptations Facultative adaptations - Including:

36. Psychological Adaptations Specialized mental organs (modules) each: Including:

37. Psychological Adaptations Remember - natural selection cannot design behavior itself Natural selection designs Psychological organs -

38. Out-of-Date Adaptations Evolution measured in generations human generation ≈ bacteria generation ≈ So, human evolution If local environments change faster than does a generation -

39. Out-of-Date Adaptations Example: Use this thinking to try and understand why most of our ancestors were never overweight, but many of us are overweight now.

40. Are All Traits Adaptations? Is the nose an adaptation for holding up glasses?

41. A Special Kind of Selection: Sexual Selection What’s up with the elaborate feathers?

42. Sexual Selection Traits spread b/c they lead to more offspring than they cost. What about traits like the peacock feathers that make an organism more vulnerable to predators?

43. Sexual Selection: The Peacock Come on Mamma. I got what you need!

44. Sexual Selection Often acts unevenly in the two sexes because of differences in reproductive rate. Reproductive Rate = Fast rate = Slow rate =

45. Sexual Selection When males > females reproductive rate (most mammals): 1. 2.

46. Sexual Selection Sexual selection favors traits that help increase the # of matings in the fast sex: 1. 2.

47. Sexual Selection Sexual selection favors traits that help increase the quality of matings in the slow sex: 1. 2.

48. Sexual Selection When males = females reproductive rate (lots of birds): 1. 2.

49. Sexual Selection What would you expect the sex differences to be like in a species in which male ≈ female reproductive rate?

50. Sexual Selection Predict the reproductive rates in this species.

51. Sexual Selection Predict the reproductive rates in this species.