White, K. G. & J. T. Wixted (1999).
Psychophysics of remembering.
Journal of the Experimental Analysis of Behavior,
71, 91-113.
We
present a new model of remembering in the context of conditional discrimination. For
procedures such as delayed matching to sample, the effect of the sample stimuli at the
time of remembering is represented by a pair of Thurstonian (normal) distributions of
effective stimulus values. The critical assumption of the model is that, based on prior
experience, each effective stimulus value is associated with a ratio of reinforcers obtained
for previous correct choices of the comparison stimuli. That ratio determines the choice
that is made on the basis of the matching law. The standard deviations of the distributions
are assumed to increase with increasing retention-interval duration, and the distance
between their means is assumed to be a function of other factors that influence overall
difficulty of the discrimination. It is a behavioral model in that choice is determined by
its reinforcement history. The model predicts that the biasing effects of the reinforcer
differential increase with decreasing discriminability and with increasing retention-
interval duration. Data from several conditions using a delayed matching-to-sample
procedure with pigeons support the predictions.
Key words: remembering, conditional discrimination, forgetting functions,
discriminability, reinforcer probability, delayed matching to sample, pigeon