Primate Behaviour

Question 1

primate basics

Answer 1

• Mammals of the order Primates
• Live in tropic/subtropic climates of Americas, Africa, Asia
• Large size range (30-200+kg)
• Large brain size compared to other mammals of similar sizes, as well as improved vision (specifically depth perception), and decreased olfactory abilities
• Most have opposable thumbs -> influence behaviour
• Slower rates of development compared to other similar sized mammals

Question 2

primate phylogenetic tree

Answer 2

• Built using genome sequence data

- Genetic difference between human and gorilla: ~1.6% (4-5% if genetic deletions included)

Question 3

new ape species identified

Answer 3

• Pongo tapanuliensis: great ape species
• First new great ape identified since the bonobo (1929)
• Identification based on: genetic (mitochondrial), anatomical (bones), and ecological data
• Location: Indonesian island of Sumatra
• Population at risk (<800 members)

Question 4

types of primate behaviours

Answer 4

• cooperative behaviour
• empathy
• altruism and fairness

Question 5

cooperative behaviour

Answer 5

• Yerkes Primate Centre: Training young chimps by putting food on top of box, but it was too heavy for 1 chimp to pull box over alone -> had to work together
• If one chimp is hungry but the other isn’t, it will still help with encouragement from other chimp (understands need for cooperation) -> this is due to reciprocity (partner will return favour in future)

Question 6

empathy

Answer 6

• ability to recognize and respond to the emotions of others; many mammals are capable of it (ie. Dogs)
• 2 branches: emotional and cognitive

Question 7

emotional branch of empathy

Answer 7

• aka: primitive empathy
• subjective state that results from emotional contagion -> responding appropriately to someone’s emotions (facial expression, posture); often unconscious
• Brain areas activated: thalamus, limbic areas, mirror neuron system

Question 8

cognitive branch of empathy

Answer 8

• conscious drive to recognize and understand another’s emotional state
• Additional brain areas activated: prefrontal cortex, language processing centres
• Limited number of mammals have been shown to be capable of cognitive empathy (ex. Elephants)

Question 9

yawn contagion

Answer 9

• yawning when others yawn; best predictor of “yawn contagion” in humans = related kin (kin > friends > acquaintances > strangers)
• • Activates many of the same areas in the brain as empathy responses
• • Association in humans: high degree of yawn contagion and high empathy
• • Lack of an association: eg. Autism (decreased empathy) -> no yawn contagion
• • Why is this important? -> as social beings, it is important to “share others’ emotions” (empathy)
• • Primates are capable of “yawn contagion”

Question 10

altruism

Answer 10

• It was previously assumed that only humans cared about altruism and welfare of others
• Study: if chimps can pick a “selfish” token that only feeds them vs. A “pro-social” token that can feed both them and their partner, they’ll choose pro-social more often
• • Only exception: if partner is demanding and puts pressure on them, pro-social choices decrease

Question 11

fairness

Answer 11

• primates recognize fairness
• Same set-up as token experiment; Capuchin monkeys had to deliver rock to experimenter to receive a reward (cucumber or grape)
• • If both receive cucumbers, they’ll both eat it, but if one receives cucumber and the other receives grapes (better food), the cucumber monkey will be upset -> recognizes that the situation is unfair
• • This recognition of fairness isn’t unique to primates, but it has been well-documented in them