Theory of Mind in Animals

1. Primates

Machiavellian Hypothesis:
•	Success in primate societies often determined by Machiavellian strategies (social exploitation)  tap expertise acquired by others (scrounge resources from them, learn from them)
•	It is this rather than physical problem-solving, foraging, tool-making, etc. that has led to primary advances in primate cognition (human and non-human)

Social Knowledge:
•	Can predict behaviour of conspecifics (other primates) based on past experience or emotional displays
•	Develop social strategies to influence others (e.g., grooming)
•	Many anecdotes:
•	Savannah baboon being chased by another stopped and looked in the distance
•	Monkeys traveled in such a way as to keep an occluder such as a tree between themselves and a human observer
•	Human raised and captive chimpanzees and bonobos follow gaze of humans to objects

•	But interpretation difficult:
•	Did baboon understand chaser’s belief, or just their behavioural reaction?
•	Do monkeys understand human’s mental state (what can see), or just that human won’t do anything aversive when s/he can’t be seen?
•	Do bonobos understand mental state of vision, or just use body or head direction cues to discover the interesting thing?

Arguments Against a Theory of Mind in Primates (i.e., no understanding that can affect others through communicative efforts):
•	Do not point to objects to share attention
•	Do not hold up objects for others to see and share
•	Do not actively give or offer objects to other individuals
•	Do not teach one another
•	Engage in simple cooperation that doesn’t require deep understanding of others

Gaze Following/Seeing
Human Infants:
•	6 to 12 months: Follow adult’s gaze (head & eyes) to side, though stop on first object in sight & don’t follow gaze behind self
•	12 to 18 months: Focus on thing adult looking at, use eyes alone, & follow gaze behind

Chimpanzees:
•	are like 18-month-old human infants
•	selected for in evolution  early detection of predators, predicting movements of others in troop
•	eye gaze important in chimp society  direct eye gaze important in friendly social relations, as well as aggression, reconciliatory periods following aggression, and chimps more drawn to those who make direct eye contact
•	if don’t find anything interesting when follow gaze, then check gaze again and re-follow

Does this mean chimps understand mental state of seeing, or does chimp merely understand behavioural configurations that are associated with successful social interactions?

Hare et al. (2000):
Experiment 2:
•	subordinate gets more food in hidden-visible condition
•	But both animals released at same time  subordinate goes to hidden location because follow dominant’s motion and dominant moves to visible location?

Experiment 3:
•	release subordinate slightly before dominant so subordinate will be half-way to location before dominant enters
•	Subordinate approached a particular location before dominant released in 77% of trials  of these trials, they approached the hidden location on 73% of trials
•	Dominant has reverse strategy  goes for visible food first, then collects hidden food at leisure  not a rigid learned strategy to go for hidden food, but a flexible strategy based on what other sees

Experiment 4:
•	Is subordinate’s choice of hidden location due to thinking food looked closer or more accessible?
•	No  choose 50-50 from hidden-visible locations when no competitor

Experiment 5:
•	Did subordinate think dominant wouldn’t go to hidden location because food harder to get behind barrier?
•	Transparent barriers  no preference for object behind barrier  with same delay preference was significant for visible location

All Experiments:
•	subordinate’s behaviour was strategic  approached hidden location, but then hesitated because dominant close by, then grabbed food when dominant turned back, rushed over to “greet” (delay) dominant, then grab hidden food when dominant not looking

2. Dogs
•	have lived with humans for thousands of years – at least 14,000, possibly 135,000
•	6- to 12-week-old puppies imprint if exposed to humans – accept humans (generally) as member of own species
•	certain characteristics have been chosen as desirable (including loyalty, affection, and possibly social insight) in humans’ breeding of dogs and in dogs’ survival?

Similarities to Humans
•	show anxiety in strange situation (if owner leaves unfamiliar room)
•	demonstrate object permanence understanding (though not mirror self-recognition)

Miklósi, Polgárdi, Topál, & Csányi (1998): 
•	two containers, each impregnated with food scent
•	experimental trials: experimenter points, bows (and looks toward), nods toward, turns head toward, or glances toward (head still) a dish
•	gesture occurred, then no gesture, then dog chooses
•	control trials: experimenter looks toward ceiling and dog allowed to choose container – before and after experimental trials

Experimenter

Food Dishes

Dog

•	find pointing, bowing, nodding easy, head-turning harder, glancing harder still (though can learn)
•	general consensus that dogs are empathic (sensitive to states of distress in humans) though no hard experimental evidence & unclear whether understand distress as a mental state
•	unlike primates, dogs live with humans
•	some learning could occur during dog’s lifetime (6-month-old dogs understand other dogs’ gestures but not humans’, 4-year-old dogs understand humans’ gestures), as well as sensitivity to cues selected for in breeding

How should primates’ and dogs’ theory of mind be characterised?
Povinelli:
•	primate social world is complex  deceive each other, have clear dominance hierarchies, have complicated and shifting alliances as means of maintaining or gaining in dominance hierarchy, are sensitive to recent interactions (whether positive or negative)
•	How?  knowledge is implicitly represented in primates, humans have “re-described” it so that it is explicit
Carruthers (1996):
•	Primates have implicit understanding and explicit understanding isn’t possible without language

What might language allow?
•	Provides means to reflect on contingencies in world (e.g., eye gaze – behaviour) to formulate and refine explicit theories

What are the advantages of explicit understanding?
•	Flexibility to think about when deception/etc. will be most effective, and what will be the best specific action on an occasion

Why are primates successful on Hare et al.’s task but not tasks in which they must understand humans’ seeing?
•	Conspecifics versus humans
•	Competitive situation

Evaluation: none of these insights likely requires a “theory of mind” (understanding of mental states) in contrast to a “theory of behaviour”  but insights are still invaluable to social life

•	Might not understand visual experience is a mental state but this has little relevance for real life if can reliably understand behavioural consequences of visual experience
•	Understanding could be both implicit and behavioural, yet still valuable

Intention
•	one person pours juice out purposely, another accidentally spills it  chimp given choice of who they would like to get juice again  no consistent preference for clumsy human
•	don’t distinguish between accidental and intentional acts
•	pouring juice out of cup not an ecologically valid test?
•	In real world there are anecdotes about one primate getting particularly angry when another primate has misled him/her  might index understanding of intentional deceit (doesn’t mean understand that deceit is done to create false beliefs, just false actions)
•	In real world are anecdotes about one female primate being aggressive to an individual who harms the female’s infant, but only when act intentional

Knowledge
•	one human, behind an occluder, hid food in one of four cups, other human stayed outside
•	chimp could choose either knowledgeable (always got food) or ignorant (never got food) human to inform regarding food whereabouts  3 of 4 chimps learned after 100 to 300 trials with accuracy around 70% in late trials
•	transfer phase: ignorant human stayed in room with bag on head, knowledgeable human watched hiding  in first five trials 3 previously correct chimps were now random

False Belief
•	primates fail a non-verbal false belief task that children pass (Call & Tomasello, 1998)
Pointing
•	if point to a box, don’t go to box unless finger happens to be closer to that box than to the other
•	but no ecological validity?  chimps don’t point in real life so examining pointing as a cue to attention is inappropriate

Imitation/Emulation
Naturalistic Observations
•	Ant dipping at Gombe  use long wand (66 cm. mean) and use free hand to swipe off into mouth
•	Ant dipping at Tai  use short stick with only 15 ants, swept off with lips
•	Both troops have long sticks available
•	Suggests imitation taking place among Gombe (imitate use of swiping action along wand)

Experimental Studies (Whiten, 1988)
•	Saw 4 ways of getting into artificial fruit
•	Twist far bolt – twist near bolt – spin pin – turn handle – lift lid
•	Poke far bolt – poke near bolt – turn pin – pull handle – lift lid
•	On third trial, chimpanzees followed sequential order observed
•	Perhaps chimps inferring “plan” of model
•	Perhaps chimps simply understand how to get fruit

Call & Tomasello (1996):
•	Strongest evidence of imitation comes from primates reared by humans or who have interacted with humans in pseudo parent-child relationship
•	These apes develop concept of intention (i.e., differentiate means from ends) that wild apes lack