Lecture 7 (Bechtold)

Question 1

rate of social monogamy in mammals?

Answer 1

Few mammalian species display exclusive mate bonding

Social monogamy in only 2-3% of mammals

Question 2

what defines a social/affiliative bond?

7

Answer 2

Ability to recognise specific individuals

Recognition associated with positive emotion affect that stimulates proximity seeking, physical interactions that reinforce positive affect and imitation

Physical separation of the individuals causes negative emotions and searching behaviour

Aggression towards intruders that threaten the exclusivity of the bond

Some element of reciprocity

Relationship bonds are long term

Social and emotional dependence between individuals that promotes survival and reproductive success

Question 3

what is natural selection?

Answer 3

evolutionary forces which favours progression of advantageous traits/ phenotypes (increase likelihood of passing on genotype)

Question 4

what is sexual selection?

Answer 4

acts on an organism’s ability to obtain or successfully copulate with a mate (often by any means necessary!)
powerful enough to produce features that are harmful to the individual’s survival.

Question 5

what leads to natural selection?

Answer 5

variation, differential reproduction, and heredity,

Question 6

what is the effect of bonding on direct fitness?

Answer 6

often bonding is associated with an apparent sacrifice of direct fitness.

Question 7

advantages to social bonding?

Answer 7

Protection against predators

Food provision

Stress reduction (fear, anxiety…)

Social learning

Social reward/positive affect
Increased chance of reproductive success

Survival/care of young

Question 8

what are altricial animals?

Answer 8

born in a very “incomplete” state that will take time/care to become fully operational, alert and active with all its senses and actions. mother care critical to survival

Question 9

what are precocial animals?

Answer 9

refers to species in which the young are relatively mature and mobile from the moment of birth or hatching.

need bonding, ie deer could just walk off and die

Question 10

Which 3 theories explain monogamy in mammals?

Answer 10

Parental care hypothesis: Benefit of a second parent produces healthier, stronger, smarter offspring.

Discrete range hypothesis: Female become intolerant of other females and occupy non-overlapping territorial ranges. Inability to prevent rival males mating and reduced access to drives monogamy.

Infanticide hypothesis: Males kill the offspring off rival males to bring the female back into oestrus. Long lactation period makes infants vulnerable. Monogamy was driven by the need for males to protect offspring

2 and 3 not mutually exclusive

Question 11

What is behavioural imprinting?

Answer 11

Phase-dependent and non-associative learning.

no positive or negative feedback, learnt regardless.

ie duckies

Question 12

What is Filial imprinting?

Answer 12

young animal learns the characteristics of its parents

Question 13

What is Fraternal imprinting?`

Answer 13

learns the characteristic of its own species

Question 14

What is sexual imprinting?

Answer 14

young animal learns the characteristics of a

desirable mate

Question 15

example of early life imprinting in birds

Answer 15

Lorenz used the graylag goose to demonstrate imprinting (He took over the maternal role for a group of goslings). also rubber ball worked.

In birds, cross-fostering leads to imprinting on first object or individual that they see, leading to fixed social and sexual preferences.

This sexual imprint is pre-programmed and occurs at an early stage in development.

Question 16

mammals and imprinting?

Answer 16

Mammals are more complex and flexible…

but sexual imprinting still occurs

Question 17

Sheep and goats (cross fostering suitability)

Answer 17

Genetically similar enough to breed and produce infertile offspring (vary rare ‘Geep’)

So amenable to cross fostering (allow the mother goat to accept and rear baby sheep and visa versa)

Question 18

Cross fostering experiments in sheep and goats

Answer 18

Kendrick 1998
mix goat kids and lambs with other species foster mother –> juveniles allowed to mix socially with members of
their own genetic species as they grew up.

Play and grooming behaviour resembles that of adopted mother (AND NOT THEIR GENETIC SPECIES)

Aggression, climbing, feeding vocalisation unaffected and resembled genetic origin

Question 19

Cross fostering and sexual preference?

Answer 19

Male sheep/goats always chose the adopted species for mating, consistent for 4 years.

Female sheep/goats revert to their own species after initially choosing foster.

Therefore males imprint strongly on their maternal species, females much less so

Question 20

Sheep and facial recognition?

Answer 20

Right temporal and medial frontal cortex cells respond more strongly to a familiar face.
This region of the brain is also implicated in humans with facial recognition

Male goats and sheep select their foster species over genetic (Oedipus boi). Females are much less selective when cross fostered

Question 21

Parental influence on mate choice in humans?

Answer 21

Women born to older fathers give stronger attraction ratings to older men.

Big study found no evidence for effect of father on female partner choice but some evidence for men choosing women that looked like their mother (yuck)

Question 22

reverse sexual imprinting in humans?

Answer 22

the Westermarck effect (after Edvard Westermarck)

Desensitized to later close sexual attraction

individuals develop sexual aversion with other individuals that were raised in the same peer or family group; stronger for women than men (parental investment, inbreeding avoidance)

Westermarck effect has since been observed in many places and cultures i.e Amish

Question 23

Primate bonding strategies

Answer 23

FOR PRIMATES:
Olfactory recognition and olfactory inputs are downregulated; recognition is based on integration of multimodal sensory cues; increased redundancy in hormonal priming for motivated behaviour; increased importance of social learning

Question 24

Small mammal bonding strategies

Answer 24

requires individual recognition by olfactory cues (also auditory, visual)

activation of neural mechanisms concerned with social reward by these cues

gender-specific hormonal priming for behavioural output