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Adaptive decisions require that decision makers factor in the subjective values of different possible outcomes, and the probability of these outcomes occurring. Subjective values depend, among other things, on how far an outcome is away in time. This can be captured by assessing an individual’s delay discounting of different options. An individual’s risk preference also affects how attractive particular choice options appear to them. In humans, probability discounting and delay discounting are often related. People who show more risky behaviors also tend to be more impulsive and less patient. Based on such findings, single-process models of delay discounting and probability discounting have been suggested. In the current study, we tested if this relationship is equally present in chimpanzees, one of human’s closest extant evolutionary relatives. We presented 23 chimpanzees with a patience task and a risky-choice task. The patience task was designed to explicitly distinguish between delay preference and self-control (i.e., the ability to wait a given delay). Still, we found no strong correlations between risk and delay preferences. As this task has not been used with humans before, we implemented a computerized version and tested it in a sample of twenty adult participants. Initial results indicate that the task is well suited to capture patience, and it makes a promising candidate to be used in behavioral delay discounting experiments in humans.
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Chimpanzee locomotor risk-taking points to the importance of parental and alloparental supervision in humans
Adolescence is generally considered the life stage with peak risk-taking among humans, though this may be specific to the type of risk. To circumvent the safety constraints that limit experiments of physical risk-taking in humans, we used the natural behavior of wild chimpanzees as a model. All chimpanzees must navigate the same arboreal substrates where falls from the tree canopy are a major cause of trauma, and therefore have clear fitness consequences. Using instances of locomotor free flight as a proxy, we found that height from the ground and sex did not predict physical risk-taking. The latter finding is similar to human and chimpanzee economic risk-taking studies. We found that physical risk-taking correlated with age, peaking in infancy and decreasing gradually thereafter through juvenility and adolescence. We hypothesize that a similar pattern would be exhibited in humans if oversight were relaxed earlier in childhood, as it is among chimpanzees.Not Available
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- Award ID(s):
- 1850328
- PAR ID:
- 10666945
- Publisher / Repository:
- Cell Press
- Date Published:
- Journal Name:
- iScience
- Volume:
- 29
- Issue:
- 1
- ISSN:
- 2589-0042
- Page Range / eLocation ID:
- 114452
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1016/j.isci.2025.114452
