Sequential stimuli and relative numerosity discriminations in pigeons.

Abstract

Pigeons were trained in symbolic matching-to-sample procedures. The sample stimuli were sequences of red and blue flashes of light. If more blue flashes appeared in a sequence, then one side key was correct and provided occasional reinforcement, and the other side key produced a short blackout. If there were more red flashes, these contingencies were reversed. The number of flashes, their ordering, flash durations, and gaps between flashes were varied in 3 experiments. The proportion of «more blue» responses was an orderly function of the proportion of blue stimuli. Varying the gaps between flashes showed that both temporal and ordinal locations were important variables. Increasing the duration of flashes increases their salience. Mechanisms for discriminating the relative numerosity of successive stimuli are discussed