Shead, N.W. & Hodgins, D.C. (2009).
Probability discounting of gains and losses: Implications for
risk attitudes and impulsivity.
Journal of the Experimental Analysis of Behavior, 92, 1-16.
Sixty college students performed three discounting tasks: probability
discounting of gains, probability discounting of losses, and delay
discounting of gains. Each task used an adjusting-amount procedure,
and participants' choices affected the amount and timing of their
remuneration for participating. Both group and individual discounting
functions from all three procedures were well fitted by hyperboloid
discounting functions. A negative correlation between the probability
discounting of gains and losses was observed, consistent with the
idea that individuals' choices on probability discounting tasks
reflect their general attitude towards risk, regardless of whether
the outcomes are gains or losses. This finding further suggests
that risk attitudes reflect the weighting an individual gives to
the lowest-valued outcome ( e.g., getting nothing when
the probabilistic outcome is a gain or actually losing when the
probabilistic outcome is a loss). According to this view,
risk-aversion indicates a tendency to overweight
the lowest-valued outcome, whereas risk-seeking indicates a
tendency to underweight it. Neither probability discounting of gains
nor probability discounting of losses were reliably correlated with
discounting of delayed gains, a result that is inconsistent with the
idea that probability discounting and delay discounting both reflect a
general tendency towards impulsivity.
Key words: risk-taking, probability discounting, delay discounting,
hyperboloid, humans