Evolutionary Psychology

Question 1

What is evolution ?

Answer 1

• Descent with modification
• Descent = a lineage of organisms characterised by hereditary similarity between parents and offspring
• Modification = changes across generations in the distribution of characteristics, or traits, in a lineage
• So evolution = the change in the frequencies of hereditary characteristics across generations in a lineage

Question 2

What causes evolution?

Answer 2

• Natural selection
• Pre-requisite: Within a species there is heritable variability of phenotypes (caused by mutations or recombination during sexual reproduction)
• Some variations result in more offspring (differential reproductive success); these offspring will themselves therefore possess these beneficial differences, i.e., natural selection

Question 3

Different types of evolutionary fitness?

Answer 3

• Classical fitness = a measure of an individual’s ability for direct reproductive success
• Inclusive fitness = a measure of an individual’s ability for both direct and indirect reproductive success (Hamilton 1964)

Question 4

What are the products of evolution?

Answer 4

• Adaptations: Inherited characteristics that emerged through natural selection because they aided in solving problems related to survival and/or reproduction. - Example: umbilical cord
• By-products: Characteristics that do not solve adaptive problems and do not have functional design. They are coupled to adaptations. - Example: belly button
• Noise: Random effects produced by chance mutations that do not affect survival and/or reproductive success.

Question 5

EP: Confirmation of Darwin’s prediction?

Answer 5

• “In the distant future … psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation.” (On the Origin of Species, 1859)
• Evolutionary Psychology: “The mind is a set of information-processing machines [modules] that were designed by natural selection to solve adaptive problems faced by our hunter-gatherer ancestors” (Cosmides & Tooby, 1997, p. 1)

Question 6

Evolutionary Psychology vs. evolutionary psychology?

Answer 6

• Evolutionary Psychology: - “A way of thinking about psychology that can be applied to any topic within it” (Cosmides & Tooby, 1997, p. 1)
• “Most important scientific revolution in the history of psychology” (David Buss)
• V.S. evolutionary psychology: (Merely another) field of inquiry; a sub-discipline/approach within psychology.

Question 7

The goal of Evolutionary Biology + Cognitive Psychology

Answer 7

• Goal is to understand the human mind/brain from an evolutionary perspective
• The mind is composed of many innate, specialised, modules ‘designed’ by natural selection
• These modules emerged through natural selection to solve pre-historical adaptive problems (1.8 million – 10,000 years ago).

Question 8

What is EP reacting against?

Answer 8

• Standard Social Science Model (SSSM):
  1. Non-human animals are rigidly controlled by their biology, human behaviour determined by culture.
  2. Human infants born with nothing apart from a few reflexes and an ability to learn.
  3. Learning is a general-purpose process used in all domains of knowledge; children learn how to behave in their culture through imitation, reward, and punishment.

Question 9

Core Tenets of EP

Answer 9

• All behaviour is a function of psychological mechanisms + input to those mechanisms
• Not generally controversial but according to proponents of EP it needs emphasising:
• “it is clear that no behavior can be produced in the absence of psychological mechanisms” (Buss, 1995)

Question 10

“Modern skulls house a stone-age mind” (Cosmides & Tooby, 1997)

Answer 10

• Natural selection designed our minds to deal with problems that our ancient ancestors faced on the African savannahs
• This was our Environment of Evolutionary Adaptedness (EEA; 1.8 million – 10,000 years ago) and still is.

Question 11

Characteristics of the EEA

Answer 11

• The EEA probably consisted of:
• Hunter/gatherer/scavenging subsistence
• Nomadic or semi-nomadic
• Low population density
• Small kin-based groupings
• Simple technology
• High infant mortality and low life expectancy
• Vulnerability (e.g., to predators, disease)
• Few lifestyle options
• Development of agriculture, living in towns, cities: Only 10,000 years ago (~1000th of human history!)

Question 12

Adaptive Problems in the EEA

Answer 12

• Our minds were designed by natural and sexual selection to solve adaptive problems faced by our hunter-gatherer ancestors:
• Surviving/avoiding predators
• Food selection
• Attracting mates
• Forming reciprocal alliances
• Parenting
• Reading others people’s minds
• All of these play a role in the success with which one’s genes are passed on. So natural selection designed mental mechanisms to solve these problems (Evolved Psychological Mechanisms)

Question 13

The Massive Modularity Hypothesis

Answer 13

-Our mind consists of many domain-specific information processing modules (Evolved Psychological Mechanisms)
-Each is “an expert in one arena of interaction with the world” (Pinker, 1997)
E.G.,
-Mate selection; Theory of mind; Perception of colour; Language; Detecting cheaters during social exchanges

Question 14

Mismatches between EEA and current environment

Answer 14

• Modern fear responses reflect ancient dangers (Ohman & Mineka, 2001)
• “Supernormal stimuli” (Barrett, 2010)

Question 15

Ultimate and Proximate Causation

Answer 15

• Evolution produces adaptations that on average increase survival/reproductive fitness.
• We do not (necessarily) do those things that maximize fitness today; we execute those adaptations that in the past increased fitness.
• WHY does a certain trait exist?
• ULTIMATE CAUSE – the reason why it increased fitness in the evolutionary past
• PROXIMATE CAUSE – the immediate psychological, physiological, biochemical, and environmental reasons

Question 16

EP of human mating behaviour

Answer 16

• Humans (of both sexes) engage in short- and long-term mating
• Human mating is inherently strategic
• These strategies are designed to solve (prehistoric) adaptive problems
• The adaptive problems differ according to:
  1) Temporal context (short- or long-term)
  2) Sex (male or female)

Question 17

Starting point 1: Sexual selection

Answer 17

• Evolution of traits that afford a direct reproductive advantage (Darwin, 1871)
• Two paths: a) Success at intersexual attraction b) Success at intrasexual competition

Question 18

Starting point 2: Parental investment theory (Trivers, 1972)

Answer 18

• The sex that invests more in offspring will be more discriminating about who they mate with
• The sex that invests less will compete more vigorously for access to valuable high-investing members of the opposite sex

Question 19

Differences between men and women in minimum obligatory parental investment

Answer 19

• Women:
• Internal fertilisation and gestation
• Lactation
• Maximum number of children is about 12
• Thus, expect women to be more discriminating
• Men:
• Donate sperm
• Expect them to be less discriminating but more vigorous in competition

Question 20

General prediction: “Short-term mating will represent a larger component of men’s sexual strategy [compared to that of women]” (Buss & Schmitt, 1993, p. 210).

Answer 20

-Adaptive problems of males in a short-term mating context:
– finding enough partners
– finding women who are sexually accessible
– minimising cost, risk and investment
– identifying women who are fertile

Question 21

Specific prediction: ‘Men will express greater desire for short-term mates than will women’

Answer 21

• Level of seeking increases from short-term to long-term for women
• Level of seeking decreases from short-term to long-term for men
• Overtime, men have more partners than woman

Question 22

Specific prediction: In a short-term mating context, ‘men will be willing to engage in intercourse after less time has elapsed in knowing a potential partner than will women’
-Clark and Hatfield (1987, 1989):

Answer 22

– Would you go out with me tonight?
– Would you come over to my apartment tonight?
– Would you go to bed with me tonight?

Question 23

Clark and Hatfield (1987) - Results

Answer 23

-Percentage who said ‘yes’
– Would you go out with me tonight? - (50% male, 50% female)
– Would you come over to my apartment tonight? (70% male, 5% female)
– Would you go to bed with me tonight? (75% male, 1% female)

Question 24

Specific prediction: Men’s preferences in a short-term mating context will reflect male short-term adaptive problems

Answer 24

• SHORT TERM: want a mate who is good looking, physically attractive, promiscuous, higher sex appeal and sexually experienced
• LONG TERM: want a partner who is committed, lower sex drive, more prudish, not as sexually experienced, less about looks

Question 25

General prediction: Women will tend to favour a long-term mating strategy (compared to men)

Answer 25

``` -Adaptive problems of women in a long-term context involve finding men who: – are able to invest – are willing to invest – offer physical protection – offer commitment – have good parenting skills – have good gene quality ```

Question 26

Specific prediction: In a long-term context, ‘women, more than men, will desire cues to a potential mate’s ability to acquire resources, including ambition, good earning capacity, professional degrees and wealth’

Answer 26

- 20 women and 28 men evaluated the importance of certain characteristics: - has a promising career - has good financial prospects - likely to succeed in their profession - likely to earn a lot of money - has a reliable future career - Long-term resource potential: women's mate preferences - Higher means for long term than short term

Question 27

Buss (1989) | -Inter-continent consistency of women’s higher valuation of financial prospects in a long-term mate compared to men:

Answer 27

- Women consistently valued money over men in all countries | - Japan and Zambia highest, Australia lowest

Question 28

EP of human mating behaviour: Some criticisms

Answer 28

-The data are often open to non-evolutionary based explanations -Take, e.g., Buss’ (1989) cross-cultural study of sex differences in the valuation of financial prospects in a long-term mate -Low socio-economic status groups highly underrepresented – The sex difference diminishes as economic inequality between the sexes diminishes

Question 29

Challenges to EP: Massive modularity?

Answer 29

- Could general mechanisms (e.g., social learning) not be applied to different adaptive problems? - The most fully articulated accounts of modularity (e.g., Fodor, 2000) posit that while some processes are indeed modular (‘input processes’), ‘central’ cognitive functions are domain general.

Question 30

Challenges to EP: Do modern skulls really house a stone-age mind?

Answer 30

- EP framework claims 10,000 years insufficient for “new complex designs” - Did natural selection just stop? - Aren’t human minds still adapting rather than already adapted? - Reliance on the unknown (unknowable?) EEA - EEA more variable than EP assumes?

Question 31

Challenges to EP: Massive modularity? (cont..) | -Evidence that modular specialisation is determined over the course of within-individual brain development

Answer 31

> Additive vs. subtractive neuronal processes > Genes only involved in the additive type… > …and yet it is the subtractive type that is responsible for modular specialisation > Specialised modules are thus the result of an individual’s history of interaction with the local environment