Lecture 3

Question 1

What was the record for the most amount of kids for male and females respectively?

Answer 1

Female: 69 kids, held by Feodor Vassilyev
Male: In 1703, he had 867 kids, held by Moulay Ismail Ibn Sharif

Question 2

What is Robert Triver’s Parental Investment Theory?

Answer 2

Different mating/reproductive strategies are based on the relative amount of investment a parent makes in an offspring. Any investment by the parent that increases the offsprings chance of survival costs in terms of the parents ability to invest in other offspring.

Question 3

Which sexes investment is generally higher?

Answer 3

Female (95% of the time) . They have a higher obligatory parental investment

Question 4

What is anisogamy?

Answer 4

Reproduction by the union of two different gametes (ova and sperm). The ova invests more energy

Question 5

How does pregnancy cause a higher investment?

Answer 5

Internal gestations have a high metabolic cost for females

Question 6

How does post-birth care cause a higher investment?

Answer 6

Example: Lactation is metabolically costly

Question 7

What percentage of carnivores and primates show paternal investment?

Answer 7

30-40% of genera.

Question 8

What are the reproductive consequences of a female investing more in offspring?

Answer 8

On average, over the course of her lifetime, an individual female will produce less offspring than an individual male.

Question 9

What is a typical females variation in reproductive success?

Answer 9

It is usually low, meaning that there is not much difference in the number of offspring between females (doesn’t differ greatly from the mean). Males, on the other hand, have a high variation.

Question 10

What is Bateman’s Principle?

Answer 10

Predicts that variability in reproductive success is greater in males than females.

Question 11

What did Brown et al find about Bateman’s Principle in humans?

Answer 11

They found that 18/19 of human societies they studied, the males had a greater variance for reproductive success.

Question 12

Why do males have greater variation in reproductive success?

Answer 12

Due to parental investment theory.

Question 13

What is the process of female reproductive strategies (4 steps)

Answer 13

1) Greater female investment
2) Individual female has potentially lower reproductive rate and number of offspring
3) Prediction: Females would be more selective about mates than males
4) Leads to process of female choice becoming a more important strategy than female-female competition.

Question 14

What is the process of male reproductive strategies? (4 steps)

Answer 14

1) Less male investment
2) Potentially higher reproductive rate
3) Prediction: Males are less choosy and search out as many fertilizations as possible to best rivals
4) Leads to process of male-male competition being more important than male choice.

Question 15

Which species shows higher male investment?

Answer 15

The Red Necked Phalarope. The male takes care of the eggs and the female courts.

Question 16

What are some characteristics of female Red Necked Phalaropes?

Answer 16

Larger than males, more brightly coloured, fight with other females for mate access, reproductive rate is potentially higher for females.

Question 17

What complicates our discussion of sexual selection in humans?

Answer 17

The fact that males invest heavily in offspring.

Question 18

What kind of spectrum do sex differences exist on?

Answer 18

A continuum. Males and females can fall at any point, but their averages are different.

Question 19

How has the size dimorphism in humans changed overtime and what does this suggest?

Answer 19

Size dimorphism has decreased, 8% difference in height and about 15-20% difference in weight. Demonstrates that direct physical competition may not be as important.

Question 20

What is same sex physical aggression viewed as?

Answer 20

An expression of competition. Aggression is motivated by competition.

Question 21

What is competition?

Answer 21

A rivalry between two or more individuals for a resource that is perceived to be insufficient or limited in quality.

Question 22

What is one of the largest and most reliable male-female behavioural differences?

Answer 22

Physical aggression-human males engage in more physical aggression than females.

Question 23

What was found in a study on same-sex homicides?

Answer 23

Out of 14 000 cases studied, 97% of the perpetrators were male. Males also make up the majority of both homicide victims and accused.

Question 24

What percentage of homicide victims and homicide accused were male in Canada in 2017?

Answer 24

Accused: 87%
Victims: 77%

Question 25

What male body traits could have been shaped by male male competition?

Answer 25

Facial hair, vocal characteristics, facial shape.

Question 26

What are secondary sex characteristics usually used for in men?

Answer 26

They are more effective at intimidating other men than they are at attracting women.

Question 27

Why is there variance in reproductive success according with male-male competition? (Batemans)

Answer 27

Some males can best other males and mate more often

Question 28

What percentage of men are descendants of Ghengis Khan?

Answer 28

0.5%

Question 29

What is social status?

Answer 29

Your relative access to contested resources within a social group by non-agonistic means (individual doesn’t use force or the threat of force to get what they want)

Question 30

What happens if one has high status?

Answer 30

Allows greater access to desirable things, and that access is typically not actively restricted by subordinates. Receivers of submissive displays.

Question 31

What did Von Rueden et al study?

Answer 31

The Tsimane people in Bolivia to see if high status males have more children than lower status.

Question 32

What types of data did Von Rueden et al collect?

Answer 32

1) Ranked all males in a social hierarchy
2) Time allocation of male activities
3) Interviews about food production and income
4) Weekly calorie count
5) Demographics, including data on offspring survival and extra-marital affairs.

Question 33

What were the results of Von Rueden et al’s study?

Answer 33

High status males had higher intramarital fertility: More affairs, but their reproductive success gains are mainly from within their marriages. Tsimane males invest in a single wife their entire reproductive careers. They also had lower offspring mortality.

Question 34

What did Hopcroft study in contemporary males?

Answer 34

Status and reproductive success.

Question 35

What kind of data did Hopcroft collect?

Answer 35

1) Number of biological children claimed by a sample of US males (Children did not have to reside in the same house or from current relationship)
2) collected data on respondents income as a form of social status

Question 36

What were the results of Hopcrofts study?

Answer 36

There was a positive relationship between income and biological children (yet we are still unsure of the proximate reasons why)

Question 37

Do high income females tend to have more children than low income?

Answer 37

No. Some studies show that educational achievement is negatively related to fertility (number of offspring). American women with a high school education have a 0.5% higher fertility rate than college educated children.

Question 38

Why don’t high income females have more children?

Answer 38

Delaying the age of your first birth lowers females reproductive outputs. Later pregnancies mean less chance to have more.

Question 39

Why is high status in women beneficial?

Answer 39

1) Proximate level: Gain success, respect, and prowess.
2) Investment in existing offspring
3) widening of mate choice options

Question 40

When female-female competition happens, what is it usually over?

Answer 40

1) Mates (sexual access to mates)
2) Resource competition
Among mammal species, competition is usually over resources

Question 41

How does female-female competition work in the primate order?

Answer 41

Food is the main limiting resource for females. Some species have a female dominance hierarchy in which access to food depends on rank.

Question 42

What is another reason female primates may compete with other females?

Answer 42

For access to male friends. They use their friends as protection from males outside the group from infanticide. It is less about sexual access, and more about attention

Question 43

What are some of the benefits that males get from having female friends?

Answer 43

Preferential grooming, preferential proximity to female, may mate with her friend

Question 44

Why does female-female competition occur over access to attention from males?

Answer 44

1) Males provide access to resources like paternal care, territorial resources for females and/or offspring
2) If males vary in quantity or quality of resources provided (ex: offspring care)

Question 45

What are the 2 types of human competition?

Answer 45

1) Direct competition

2) Indirect competition

Question 46

What is direct competition?

Answer 46

Force or threats of force are used to exclude same sex rivals from resources. You can see this type of competition

Question 47

What is indirect competition?

Answer 47

Instigator manipulates others to attack the victim, or by other means makes use of the social structure in order to harm the target.

Question 48

What is the goal of using indirect tactics?

Answer 48

1) Ostracism- may be a way to exclude an individual from an important resource
2) Competitor derogation- Any act that is performed for the purpose of decreasing, relative to oneself, a rivals value

Question 49

What was the study by Vaillancourt and Sharma done on competitor derogation in women>

Answer 49

86 heterosexual females were paired with either a friend or a strange, then randomly assigned to 2 experimental conditions: 1) Participants exposed to a conservatively dressed, 21 year old, caucasian female. 2) Same female, except dressed provocatively.
Target does not interact with participants. Wanted to measure how intolerant the females were to the provocatively dressed female

Question 50

How was intolerance measured in the study by Vaillancourt and Sharma?

Answer 50

Video and audio recordings captured the people before and after the target entered the room. Video clips were presented to 13 other women for classification on 2 DVS 1) Whether or not they thought the participant exhibited “bitchy” behaviour (indirect aggression) and 2) how bitchy the reaction was on a scale of 1-10

Question 51

What was the operational definition of bitchy?

Answer 51

Negative facial expressions, disgust, eye rolls, dismissive and avoidant behaviours, one-overs, death stares, body postures, mocking, sarcasm etc

Question 52

What were the results of the Vaillancourt and Sharma study?

Answer 52

Conservative bitchiness scores were lower than sexy. Friend and stranger had similar scores. Sexy: Had high bitchiness scores, were more likely to demonstrate bitchy behaviour, ridicule her appearance, and suggest she was sexually behaviour. All comments were made after the target left, with the exception of one.