Core - Chapter 2 - Evolution Flashcards
Describe a study on evolution, humans and chimps
Professor Tetsuro Matsuzawa (2007)
Describe a study on disgust in pregnant women
Dan Fessler (University of California) Emotion of disgust allowed our ancestors to survive long enough to produce offspring. Fessler (2006)
Describe a study on disgust
Curtis et al. (2004)
Describe some ethical considerations regarding research into genetic influences on behavior
Identifying particular genes involved in hereditary diseases - may pose risks to participants because of the link between genetic heritage and people’s life. Can be problematic for family or, if misused, information can be stigmatizing and may affect people’s ability to get jobs or insurance.
Can reveal unexpected information that may hard research participants, e.g. misattributed paternity, unrevealed adoptions, finding out that one has the gene which may cause the outbreak of a disease.
Professor Tetsuro Matsuzawa (2007)
Examined spacial memory in young chimps. Three pairs of chimps were taught to recognize the numerals from 1 to 9 on a computer monitor. Both the chimps and the human participants were later seated at a computer terminal, where numerals flashed up very briefly on a touch-screen monitor in a random sequence. The numbers were then replaces with blank squares, and the participants had to remember which numeral appeared in which location, and touch the squares in the appropriate sequence.
Human participants made many errors, and accuracy decreased as the numbers were replaces with blanks more quickly. The chimpanzees showed no difference when the numerals were shown for shorter durations.
Necessary adaptation for chimpanzees to have this type of memory so they can remember where food resources or danger are in the rainforest. Humans may have evolved away from it through the steady resource of agricultural yield, or surrendered the skill to develop language.
Curtis et al. (2004)
Research on the internet to test whether there were patterns in people’s disgust responses. An online survey showed participants 20 images and for each image they were asked to rank their level of disgust. 7 of the 20 pairs were infectious or potentially harmful to the immune system, others were visually similar but non-infectious. There were 77 000 participants from 165 countries. Findings confirmed that the disgust reaction was most strongly elicited for those images which threaten one’s immune system. The disgust reaction also decreased with age and were higher in women.
Limitations: hard to empirically test some evolution-based theories - confirmation bias may occur. Little is known about early homo sapiens - hypothetical claims of how we “used to be”. Evolutionary arguments often underestimate the role of cultural influences in shaping behavior.
Fessler (2006)
Nausea experience by women in their first trimester of pregnancy. An infusion of hormones lowers the expectant mother’s immune system so as not to fight the new foreign genetic material in her womb. Hypothesis was that nausea response helps to compensate for the suppressed immune system.
496 healthy pregnant women between the ages of 18 and 50 were gathered and asked to consider 32 potentially stomach-turning scenarios (walking barefoot on an earthworm, someone sticking a fish hook through their finger, maggots on a piece of meat in an outdoor waste bin). Before asking the women to rank the scenarios, Fessler posed a series of questions, designed to determine whether they were experiencing morning sickness.
Women in the first trimester scored much higher than those in the second and third trimester. When Fessler controlled the study for morning sickness, the response only held for disgusting scenarios involving food (maggot example). Many of the diseases are food-borne, but our ancestors could not be picky. Natural selection may have helped the reproduction by increasing susceptibility to food.
