Johnstone, V., & Alsop, B. (1996).
Human signal-detection performance: Effects of signal presentation probabilities and reinforcer distributions.
Journal of the Experimental Analysis of Behavior,
66, 243-263.
University students participated in one of four standard
two-choice signal-detection experiments in which signal
presentation probability was varied and the reinforcement
distribution was held constant and equal. In Experiments 1, 3 and
4, subjects' performance showed a systematic response bias for
reporting the stimulus presented least often. Experiments 1 and 4
showed that this effect was reliable with extended training and
monetary, rather than point, reinforcement. In Experiment 2, all
correct responses were signaled in some way, and this produced
the opposite relationship between signal presentation probability
and response bias. Experiments 1 and 3 found that explicitly
deducting money (intended as punishment) for equal numbers of
incorrect responses on each alternative, or varying the obtained
overall rate of reinforcement, produced no clear change in
response bias. The bias, shown by humans, for reporting the
stimulus presented least often remains a challenge for theories
of stimulus detection.
Key words: signal detection, signal presentation probability,
reinforcer distribution, discriminability, response bias, humans