Een van de experimenten door Frans de Waal uitgevoerd met
chimpansees gaat over “onrechtvaardige beloning”. Een chimpansee weigert een
beloning met voedsel als hij ziet dat een andere chimpansee lekkerder voedsel
krijgt.
Het experiment wordt nog
eens dunnetjes overgedaan door het Max Planck Instituut in Leipzig;
samenvatting hieronder. Ik begrijp niet waarom hiervoor chimpansees in gevangenschap
gehouden moeten worden. Welk
belang hebben dit soort experimenten voor de dieren?
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Chimpanzees’
refusal of less-preferred food when an experimenter has previously provided
preferred food to a conspecific has been taken as evidence for a sense of
fairness. Here, we present a novel hypothesis—the social disappointment
hypothesis—according to which food refusals express chimpanzees' disappointment
in the human experimenter for not rewarding them as well as they could have. We tested
this hypothesis using a two-by-two design in which food was either distributed
by an experimenter or a machine and with a partner present or absent. We found
that chimpanzees were more likely to reject food when it was distributed by an
experimenter rather than by a machine and that they were not more likely to do
so when a partner was present. These results suggest that chimpanzees’ refusal
of less-preferred food stems from social disappointment in the experimenter and
not from a sense of fairness.
