Non-spatial delayed alternation by the pigeon.

Pigeons were trained on a non-spatial delayed alternation task in which the color not pecked on the previous trial was correct. When varying delays were interposed between trials, alternation accuracy decreased as a function of delay, but remained greater than chance with a 45-sec delay. Successful alternation on the longer delays was accomplished without behavioral mediation of the delay intervals. Also, during initial testing when a position cue was available in addition to the color cue after incorrect trials, alternation accuracy was greater after a preceding incorrect trial than after a correct trial. When the position cue was removed, no differences occurred as a function of the outcome of the preceding trial.