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Updated: May 23, 2026
13:04
Measuring the Subjective Value of Risky and Ambiguous Options using Experimental Economics and Functional MRI Methods
Published on: September 19, 2012
Risk and the evolution of human exchange
Hillard S Kaplan1, Eric Schniter, Vernon L Smith
1Department of Anthropology, University of New Mexico, Albuquerque, NM 87131, USA. hkaplan@unm.edu
Proceedings. Biological Sciences
|April 20, 2012
Summary
Humans engage in extensive food sharing to mitigate risks from unpredictable resource acquisition. This behavior, driven by the expectation of reciprocity, is crucial for buffering against high-variance foraging outcomes.
Area of Science:
- Evolutionary Anthropology
- Behavioral Economics
- Social Psychology
Background:
- Human sociality is characterized by extensive non-kin exchange, unlike other species.
- This exchange may have evolved to buffer risks associated with specialized diets, particularly from hunting.
- Existing evidence for reciprocity is challenged by the 'tolerated theft' hypothesis.
Purpose of the Study:
- To test the risk-reduction hypothesis for reciprocal exchange.
- To investigate if individuals form reciprocal relationships in response to resource acquisition variance.
- To determine if this occurs without external enforcement of agreements.
Main Methods:
- A laboratory experiment using a virtual world simulation.
- Participants foraged in either high-mean, high-variance (HV) or low-mean, low-variance (LV) resource patches.
- The design allowed for voluntary resource transfers between individuals.
Main Results:
- Minimal resource sharing occurred after low-variance (LV) foraging.
- Significant increases in sharing were observed among high-variance (HV) foragers over time.
- Individuals demonstrated a predisposition to evaluate exchange gains.
Conclusions:
- Human propensity for reciprocal trading relationships is strongly supported.
- Individuals respond to unsynchronized variance in resource availability through endogenous exchange.
- Exchange serves as a key strategy for managing foraging risks in humans.
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