See erratum, January 2004, 81, 4.
Pietras, C. J., Locey, M. L., & Hackenberg, T. D. (2003).
Human risky choice under temporal constraints: Tests on an energy-budget model.
Journal of the Experimental Analysis of Behavior,
80, 59-74.
Risk-sensitive foraging models predict that choice between fixed
and variable food delays should be influenced by an organism's
energy budget. To investigate whether the predictions of these
models could be extended to choice in humans, risk sensitivity in
4 adults was investigated under laboratory conditions designed to
model positive and negative energy budgets. Subjects chose
between fixed and variable trial durations with the same mean
value. An energy requirement was modeled by requiring that five
trials be completed within a limited time period for points
delivered at the end of the period (block of trials) to be
exchanged later for money. Manipulating the duration of this time
period generated positive and negative earnings budgets (or,
alternatively, "time budgets"). Choices were consistent with
the predictions of energy-budget models: The fixed-delay option
was strongly preferred under positive earnings-budget conditions
and the variable-delay option was strongly preferred under
negative earnings-budget conditions. Within-block (or
trial-by-trial) choices were also frequently consistent with the
predictions of a dynamic optimization model, indicating that
choice was simultaneously sensitive to the temporal requirements,
delays associated with fixed and variable choices on the upcoming
trial, cumulative delays within the block of trials, and trial
position within a block.
Key words: risky choice, energy budget, optimal foraging theory,
monetary outcomes, adult humans