When is a choice not a choice? Pigeons fail to inhibit incorrect responses on a go/no-go midsession reversal task.

In a 2-stimulus visual discrimination choice task with a reversal in reward contingencies midway through each session, pigeons produce a surprising number of both anticipatory errors (i.e., responding to the second-correct stimulus before the reversal) and perseverative errors (i.e., responding to the first-correct stimulus after the reversal). Here, we used a go/no-go version of the task to examine the degree to which these errors can be attributed to failure to inhibit incorrect responses near the reversal. We presented pigeons with either a green or red stimulus (randomized across trials), with pecks to 1 reinforced with food and pecks to the other stimulus leading to a 10-s time-out; the reward versus time-out contingencies reversed after 40 trials. Pigeons rarely withheld responses when reward was provided for pecking, but produced many incorrect pecks near the reversal. Subsequent experiments examined these errors with longer sessions and multiple reversals, as well as on choice tasks. Our results suggest that pigeons' errors may be due to an inability to inhibit incorrect responses rather than a deliberate choice of the incorrect stimulus on simultaneous discrimination midsession reversal procedures. Results suggest that pigeons learned independent rules about the 2 stimuli, and that training with multiple reversals changed the rules that governed pigeons' responding. (PsycINFO Database Record