Rasmussen, E.B. & Newland, M.C. (2008).
Asymmetry of reinforcement and punishment in human choice.
Journal of the Experimental Analysis of Behavior, 89, 157-167.
The hypothesis that a penny lost is valued more highly than a penny earned
was tested in human choice. Five participants clicked a computer mouse under
concurrent variable-interval schedules of monetary reinforcement. In the
no-punishment condition, the schedules arranged monetary gain. In the
punishment conditions, a schedule of monetary loss was superimposed on
one response alternative. Deviations from generalized matching using
the free parameters c (sensitivity to reinforcement) and log k (bias)
were compared in the no-punishment and punishment conditions. The
no-punishment conditions yielded values of log k that approximated zero
for all participants, indicating no bias. In the punishment condition,
values of log k deviated substantially from zero, revealing a 3-fold bias
toward the unpunished alternative. Moreover, the c parameters were
substantially smaller in punished conditions. The values for bias and
sensitivity under punishment did not change significantly when the
measure of net reinforcers (gains minus losses) was applied to the
analysis. These results mean that punishment reduced the sensitivity
of behavior to reinforcement and biased performance toward the
unpunished alternative. We concluded that a single punisher subtracted
more value than a single reinforcer added, indicating an asymmetry in
the law of effect.
Key words: choice, punishment, matching law, concurrent VI VI schedules, monetary gain, monetary loss, symmetrical law of effect, humans