Theory of mind

• What do animals know about the minds of others?

  • People make inferences about mental states of others = theory of mind - develops during childhood
  • know other people have thoughts, feelings, beliefs, intentions
• evidence of ToM in deception

  • numerous observations of apparent deception in wild

  alternate explanations

  • lack of control - don't know history of animals - what happened on different circumstance?
  • cherry-picking - widespread behaviours or rare occurrences
• Chimpanzee & cups

  • observes food while being hidden by cup & then add cup
  • 2 experimenters enter:
  • Helpful experimenter uncovers food if chimp points at correct cup - chimp behaves normally
  • Unhelpful experimenter uncovers food if chimp points at wrong cup - chimp decieves
• Chimpanzees & lights 


  • red light = able to points at empty cup
  • green = food cup
  • Cup & light tasks = don't require ToM - essentially visual discrimination tasks - learn links
• Attribution of knowldge 


  • can chimpanzee can infer mental states beyond association between individual & rewards
  • barrier between chimpanzee & 4 cups - can't see
  • researcher hides food - observes
  • 2nd researcher enters - both point to different cups
  • receives food if points at correct cup
  • If understands knowledge states of researchers = should understand 1st researcher knows where food is & will choose correct
• Attribution of knowledge - results

  • Chimpanzees can solve - understood what experimenters knew?
  • doesn't require ToM - may point to location indicate person longer there - visual discrimination task
  • not solving through ToM - solving task very slowly - acquisition taking over 100 trials - what discrimination task look like - associative learning slow
• Attribution of knowledge - 2nd experiment 


  • 2 observers - 1 bag on head - 3rd person enters, places food, leaves
  • "knower" should know where food placed - watching
  • "guesser" doesn't - couldn't see
  • chimpanzee had to choose 1 - after training - passed
  • could still be visual discrimination
• Begging

  • Chimpanzees had attentive & inattentive trainer = should beg more from attentive trainer - appear more likely to give food
  • didn't reliably learn to beg from attentive trainer
  • 1 old chimp learned - due to extensive experience with people? - could've learnt to discriminate relevant visual stimuli
• Begging - experiment may failed because

  • co-operative - competition for food might be more natural
  • cross-species
• Competition for food 


  • dominant & subordinate chimp opposite each other
  • food only visible to subordinate
  • released into arena
  • subordinate takes food only when dominant doesn't see placement
  • could be discrimination even over 64 trials & repeated training