Monkeys choose as if maximizing utility compatible with basic principles of revealed preference theory

Area of Science:

• Behavioral Economics
• Primate Cognition
• Neuroscience

Background:

• Revealed preference theory models consumer choices as utility maximization.
• Empirical implementation in animals is lacking to establish a common biological basis for choice.
• Understanding animal decision-making can illuminate fundamental economic principles.

Purpose of the Study:

• To empirically test revealed preference theory in non-human primates.
• To establish a common biological basis for economic decision-making.
• To investigate if rhesus monkeys make choices consistent with utility maximization.

Main Methods:

• Measured rhesus monkeys' choices between bundles of two liquids.
• Analyzed choice frequency to model indifference curves and marginal rate of substitution.
• Tested for transitivity and the Weak Axiom of Revealed Preference (WARP).

Main Results:

• Monkey choices aligned with revealed preference theory, showing trade-offs and indifference.
• Indifference maps exhibited properties like linearity, convexity, and varying slopes.
• Preferences were internally consistent (transitive) and satisfied WARP, indicating choice optimality.

Conclusions:

• Rhesus monkeys behave as if maximizing utility, demonstrating rational economic decision-making.
• Findings support a stochastic version of revealed preference theory in animals.
• This study provides empirical evidence for a common biological basis of economic choice.