1. LO #11: Examine one evolutionary explanation of behavior

2. Darwin’s Theory of Natural Selection
Those members of a species who have characteristics which are better suited to the environment will be more likely to survive, breed and thus pass on these traits

3. Galapagos Islands
Darwin observed that Finches on different islands had different types of beaks that were each suited to getting to the food available in their particular habitat
He concluded that the process of natural selection over several generations resulted in adaptation which means the best beak was passed down until it was the only beak

4. Interesting Fact
Darwin did not know how traits were passed down to the offspring through genes

5. Link from Animals to Humans
In The Descent of Man (1871) Darwin noted that humans have a number of behaviors in common with other animals including
mate selection
love of mother for offspring
self-preservation
Darwin, thus, laid the foundation for psychologists to study animals as a way of gaining insight into human behavior.

6. Is this the result of evolution in humans?

7. Spatial Memory (Matsuzawa, 2007)
AIM: to study spatial memory in chimpanzees and humans
PROCEDURE:
Chimps were taught to recognize numbers 1-9 on a computer monitor
Later, chimps and humans were shown numbers flashed briefly on a computer screen in random sequence
The numbers were then replaced with blank squares, and the participant had to remember which number appeared in which location and touch the square in the appropriate sequence

8. Findings
Human participants made many errors while chimps showed remarkable memory for the spatial distribution of the numbers
Psychologists argue that spatial memory in chimps has adapted over time so that they can find scarce food resources
Humans don’t need this skill to survive, so this memory power might now be used by humans to develop language memory

9. Disgust Study (Fessler, 2006)
AIM:
To prove that pregnant women experience nausea because it helps them avoid potentially harmful food that their bodies could not fight off with a suppressed immune system.
Fact:
The immune system in pregnant women is suppressed so that the body won’t try to fight off the foreign genetic material in her womb

10. METHOD
496 pregnant women were given a survey to determine whether they were experiencing morning sickness
They were then asked to consider 32 potentially stomach-turning scenarios (ex. maggots on a piece of meat, a fish hook stuck through a finger) and respond with levels of disgust

11. FINDINGS
Only the disgusting scenarios involving food earned the highest ratings of disgust
Women who were in the first trimester of pregnancy scored higher on the disgust scale
Fessler concluded that natural selection produced the nausea response in pregnant women so they would avoid foods that were a higher risk for disease, especially during the first trimester when they were most susceptible

12. Internet Disgust Study (Curtis, 2004)
AIM: To compare disgust responses to images of infectious or potentially harmful things to images of harmless things
METHOD: 77,000 male and female participants from 165 different countries were shown computer images of harmful and harmless things. For each image they were asked to rank their level of disgust

13. FINDINGS
The disgust reaction was the strongest for images that threatened the immune system
Disgust reactions decreased with age
Women were more disgusted than men
This supports the idea that disgust is a key to successful reproduction and thus survival of the species

14. Limitations of Evolutionary Evidence
Confirmation bias is possible where the research see what they expect to see
This is true because some theories are difficult to test empirically
We don’t really know what the behavior of early Homo Sapiens was
The evidence often underestimates the role of cultural influences

15. LO #12: Discuss Ethical Considerations in research into genetic influences on behavior
Participants should be informed of the aim, procedures, and any potential harm (including implications/predispositions for unwanted condition) and give their consent.
This must be done in plain language
Right to withdraw

16. Ethical Considerations (cont.)
Confidentiality and privacy should be protected
Participants must be informed what will happen to any genetic information obtained as part of the study
Reason: Genetic info can be misused by stigmatizing participants, affecting their ability to get jobs, insurance. It can even affect their legal rights.

17. Ethical Considerations (cont.)
Confidentiality can be protected with coding information or anonymizing the sample (this means even researchers cannot link results to individual people)
Unfortunately, this limits the scientific results

18. Ethical Considerations (cont.)
Genetic research can reveal unexpected information that may harm participants
Some examples are misattributed paternity, adoption, carrier of a genetic disorder
Counseling should be available for former participants

19. Ethical Considerations (cont.)
Religious and cultural issues
Cultural objections (genetic research incongruent with culture)

20. Ethical Considerations (cont.)
Political misuse of research
findings are used to marginalize a group in society
(eg. eugenics)