Human behaviour

Question 1

what characteristics make homo sapiens different to other animals?

Answer 1

widest geographical range

anatomy:

• largest relative brain size
• unique obligatory bipedal locomotion
• loss of body hair

behaviour:

• very social
• continuous (non-seasonal) sexual activity
• many different mating systems
• v sophisticated verbal + non-verbal communication

Question 2

who was Wilson and what did he do?

Answer 2

1st biologist that tried to unite animal behaviour and ecology with human social sciences

used evolutionary principles

took a reductionist
standpoint

called this new science Sociobiology

Question 3

what were Wilson’s thoughts on nature vs nurture?

Answer 3

denied the concept of ‘tabula rasa’ (clean slate)
i.e. that individuals are born with no innate mental concept
.:. he denied nurture over nature

Question 4

why did Wilson’s experiment spark a vehement debate?

Answer 4

right and left wing are offended

re-ignited the nature vs nurture debate

accused of racism, sexual discrimination and eugenics

Question 5

describe the example of of foraging in Ache nomadic foragers

Answer 5

live in groups 3-160 people

men hunt

women + children collect fruits, plants insects

diet:
56% meat (high calorie)
26% plants + insects
18% honey

Question 6

what was the prediction for whether or not optimal foraging theory can be used to predict food choice?

Answer 6

unprofitable food (prey) i.e. with low calorific return per hour, should be ignored

Question 7

what happened when guns were given to the Ache foragers in the 1980s?

Answer 7

increased food return rate of hunters from 910 cal/hr with bow and arrow, to 2360 cal/hr with guns

hunters spend less time than bow hunters pursuing difficult prey
-> they were no longer profitable

Question 8

give an example of evolution related to behaviour in humans

i.e. on Bajau people

Answer 8

dive for food and profit
- culture is built on water but not all dive

their spleens are all larger than those in the land dwelling population
- due to mutation PDE10A

Question 9

how is the reproductive physiology of sexes different?

what else may be different between sexes?

Answer 9

females
- make large initial parental investment
(large ovum, long gestation and lactation)

males
- make small initial parental investment

reproductive capacity
= max no. of offspring in a lifetime

Question 10

what is the reproductive success of each sex limited by?

what does sexual conflict have implications for?

Answer 10

females
= quality of partners

males
= no. of partners

mate choice
mating tactics
sperm competition

Question 11

describe human mate choice

Answer 11

all human societies have strong ideas about the attributes of potential breeding partners

Question 12

what are the predictions for human mate choice based on evolutionary theory?

Answer 12

males should be interested in mating with young, fertile females that can produce many offspring

females should seek wealthy males that can provide resources for offspring

Question 13

do humans have mating signals?

Answer 13

even though ovulation is concealed in humans

females can still ‘advertise’ their fertile period
- facial attraction for males is higher in ovulating females

Question 14

give an experiment where females displayed mating signals

Answer 14

lap-dancers earned more money per shift when they were in their fertile period

naturally-cycling lap-dancers earned more than pill users

so there must be some cue to advertise their fertile period

Question 15

describe parental care in Hadza hunter-gatherers

Answer 15

males spent more time with their children, if fewer single females were in the camp

-> trade-off between parental care and new matings

Question 16

why is the evolutionary approach to human behaviour powerful?

Answer 16

it replaces several currencies by 1
= potential reproductive success

it allows researches to develop models and test these models quantitatively

Question 17

what are the difficulties with evolutionary human behaviour?

Answer 17

it is difficult or illegal to carry out experiments on humans

(e. g. manipulate reproductive success)
- > so studies are observational or correlative
- > results are often open to alternative explanations

evolutionary approach does not imply that all behaviours are adaptive

Question 18

give examples to explain why ‘evolutionary approach does not imply that all behaviours are adaptive ‘

Answer 18

evolutionary lag due to lack of adaptation to artificial environment
- e.g. eating lots of fat in the past may have been adaptive in past, but not anymore

pleiotropy
- i.e. beneficial genes may have -ve side effects

evolutionary dynamics are driven by fluctuating landscapes