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Unit 34 – Experimental Monkey Business

Difficulty: Medium/hard

Time: 6 minutes

The following passage has been adapted from Not A Chimp – The Hunt To Find The Genes That Make Us Human, by Jeremy Taylor

Researcher, Brian Hare, decided to create an experimental set-up where he could frame the ‘seeing-knowing’ question in the context of competition for food between dominant and a subordinate chimp. The two chimps were separated by screens, which could be raised or lowered, from a central chamber which contained two barriers made out of opaque cloth bags. Both animals were allowed to watch while the experimenter placed two pieces of food in the central chamber, sometimes in the open and sometimes behind one of the barriers. Then both chimps were allowed into the chamber. The dominant, of course, took all the pieces of food it could see, and if both pieces had been placed in the open, it grabbed the lot. Occasionally, however, the experimenter had placed a piece of food behind one of the barriers in a way that was difficult for the dominant chimp to monitor. The question was whether or not the subordinate would preferentially go for the food only it could see, because it had been placed on its side of a barrier. The subordinate was given a very slight head start to encourage it to compete with the dominant and to ensure that it was not simply reacting to the dominant’s behaviour on release, but on the remembered ‘who saw what?’ condition when the chamber was baited.
Their measure of the choice the subordinate made was based on the completeness of its approach (half-way toward the barrier), and full approach, when the subordinate crossed the half-way line in the right direction.
Their results showed that subordinates did indeed go toward the food that only they could see much more often than the food that both they and the dominant could see (because it was either out in the open or the dominant had seen it placed behind a barrier). This suggested to Hare that they did understand something about seeing and not seeing. But did they understand anything about seeing being equivalent to knowing?
In a follow-up experiment the subordinate was always allowed to witness one piece of food being placed on its side of one or another of the barriers. In the first condition, the dominant was also allowed to witness the action; in the second condition the dominant was not allowed to see and was thus ignorant of food location; and in a third condition the dominant was misinformed about the food location in that he was first allowed to watch the food being placed, but the food was switched while his screen was subsequently lowered. The screen was always completely lowered on the dominant’s side for a few seconds before the subordinate, then the dominant, were released into the chamber. If the subordinate had remembered whether or not the dominant was looking, in the past, at the crucial moment when food was either placed or switched, and if he could thus compute that looking was akin to seeing (was akin to knowing), he should approach and retrieve the food more often when the dominant was either uninformed or misinformed about where it was, and thus avoid a bashing. He did.


1. Which of the following aspects of natural wild life is not simulated in any way in the experiments?

  • A      Foraging for food
  • B      Competition
  • C      Predation
  • D      Nesting


2. A valid criticism of the measure of choice used in the first experiment would be?

  • A      It has nothing to do with whether or not the subordinate takes the food
  • B      It doesn’t account for the subordinate’s reaction to the dominant’s behavior
  • C      The chimp would have been aware of the line drawn on the floor
  • D      It doesn’t account for the speed of the chimp’s approach


3. Based on information provided in the passage the key difference between the preliminary and follow-up experiments was:

  • A      The use of different chimpanzees
  • B      The inclusion of the condition in which the dominant was misinformed
  • C      The provision of the opportunity for the subordinate chimp to share
  • D      The order in which the chimps were released into the chamber


4. What do the findings of the experiments suggest about Chimpanzees?

A      They operate in a strictly hierarchical society
B      They make decisions based on what others do
C      They learn by observation of others
D      They have the cognitive capacity to make deductions based on evidence

  • 1-d, 2-d, 3-b, 4-d

    one side of me is telling me that ive invested in too much of ds, the other side is saying stop procrastinating.


    June 14, 2012

  • Answers:
    Q1: C
    the experiment is set in the context of two chimps, one dominant, one subordinate (competition) trying to get food (foraging). They start each experiment in their own chambers and return there after each round (nesting). Predation would be when a carnivorous animal from another species hunts the chimps. The other elements are at least vaguely simulated, but predation is not part of the experiment in any way.

    Q2: A
    In both experiments, the subordinate chimp was released a few seconds before the dominant so that his behaviour would not be dictated by the other. This rules out B. C is wrong because the chimp’s awareness of the line on the floor is irrelevant unless it has some ridiculous phobia of crossing lines. It’s a variable the experimenters would have needed to account for in the experiment but is not directly linked to the measure of choice which they used. D is also wrong because the speed of the chimp’s approach is not a metric that they wanted to record. The experiment was to determine whether or not the chimp understood that the other chimp did not know where the food was. The method of finding out the answer was to ask; will the subordinate take the food more often if we hide the location of the food from the dominant chimp? Their measure of choice doesn’t count whether or not the chimp does this, it only measures how far into the chamber the chimp moves. A is therefore the valid answer.

    Q3: B
    Whether or not they used different chimpanzees was not mentioned. If they did it would have been an experimental variable, not a key point of the test. There was no change made, according to the text, that would have enabled the chimps share the food. They were in the room together so that was up to them.
    It’s a poorly constructed sentence, but:
    “The screen was always completely lowered on the dominant’s side for a few seconds before the subordinate, then the dominant, were released into the chamber.” this shows that the order in which they were released did not change. The difference in the follow-up was the inclusion of different conditions relating to the placement of the food.

    Q4: D
    “The man but the food behind the screen. The other chimp cannot see the food behind the screen. Therefore the other chimp does not know that there is food behind the screen.” This is the deduction that the subordinate chimp must make before going for the food. He did, and this suggests that they have the capacity to make deductions like this one.
    The hierarchy of chimp society was not a finding, it was an established fact which the researchers acknowledged and incorporated into the experiment (sub and dominant). B would have been true if it was ‘they make decisions based on what they think others KNOW’. They didn’t appear to learn anything also. They made deductions and acted upon them. Learning by observation would be watching something happen and them imitating it.

    Gamsat Sample Questions

    June 14, 2012

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