Rate of Response-Independent Events as Discriminative Stimuli

The study of stimulus rates is relevant to understanding how discrete events integrated in time come to function as a single molar unit that can be discriminated from other comparable units. Two experiments examined the roles of stimulus rates as discriminative stimuli in a conditional discrimination paradigm. Pigeons responding according to a fixed interval (FI) schedule of reinforcement were presented concurrently with pairs of stimulus rates (response-independent blackouts of the operant boxes), so that access to food was granted if the pigeons pecked a comparison key associated to each stimulus rate. One-blackout versus two-blackouts stimulus rates were used on the first experiment, whereas two- and three-blackouts were used in the second experiment. The results replicate previous findings congruent with a Weber\u27s law interpretation, emphasizing the relative difference in stimulus magnitude as the controlling factor. The concomitant pattern of responding produced by FI schedule requirements is also proposed to influence the accuracy of the discrimination. Finally, some further implications of the results for the analysis of molar variables are discussed