Win-stay/lose-shift and win-shift/lose-stay learning by pigeons in the absence of overt response mediation.

Win-stay/lose-shift and win-shift/lose-stay behavior in pigeons was compared using a two-alternative conditional discrimination for which the number of trials involving each of the task components could be precisely controlled. One group was rewarded for pecking the location just pecked if those pecks were followed by food and for pecking the other location if those pecks were not followed by food (win-stay/lose-shift). Another group was rewarded for pecking the location just pecked if those pecks were not followed by food and for pecking the other location if those pecks were followed by food (win-shift/lose-stay). With increasing delay to comparison choice, pigeons were more accurate on trials when initial pecking was followed by the absence of food than by food (Experiment 1). However, when hypothesized overt response mediation was discouraged (Experiment 2), a win-stay superiority effect emerged with increasing delay to comparison choice. Thus, unlike rats, pigeons may be somewhat predisposed to repeat a response to a location to which responses have been previously rewarded.