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Endowment effects in gorillas (Gorilla gorilla).
Lindsey A Drayton1, Sarah F Brosnan, Jodi Carrigan
1Zoo Atlanta.
Journal of Comparative Psychology (Washington, D.C. : 1983)
|September 25, 2013
Summary
Western lowland gorillas exhibit endowment effects with food items, showing a stronger response than chimpanzees. This comparative study sheds light on the mechanisms behind endowment effects in primates.
Area of Science:
- Comparative psychology
- Primate behavior
- Cognitive evolution
Background:
- Endowment effects, the tendency to overvalue items one owns, are increasingly reported in nonhuman primates.
- However, the underlying mechanisms driving these effects across species remain poorly understood.
- Investigating endowment effects in diverse primate species can reveal behavioral nuances crucial for understanding their evolutionary basis.
Purpose of the Study:
- To investigate endowment effects in western lowland gorillas (Gorilla gorilla).
- To compare gorilla endowment effects with those previously observed in chimpanzees (Pan troglodytes) and orangutans (Pongo spp.).
- To contribute to hypotheses regarding the mechanisms and evolutionary factors shaping primate endowment effects.
Main Methods:
- Utilized a standardized experimental paradigm previously employed with chimpanzees and orangutans.
- Tested western lowland gorillas' endowment effects using both food and nonfood items.
- Employed statistical analyses to compare effect sizes across species.
Main Results:
- Gorillas demonstrated significant endowment effects for food items but not for nonfood items.
- The endowment effect in gorillas was statistically stronger than in chimpanzees.
- Gorilla endowment effects were not statistically stronger than those observed in orangutans.
Conclusions:
- Findings suggest that primate endowment effects may be linked to inhibitory control or risk aversion.
- The results highlight species-specific differences in the manifestation of endowment effects.
- Further research is warranted to elucidate the precise cognitive and ecological factors influencing these effects in primates.
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