Behavioural Processes 41 (1997) 227 – 236 Win-stay/lose-shift and win-shift/lose-stay learning by pigeons in the absence of overt response mediation Christopher K. Randall, Thomas R. Zentall * Department of Psychology, Uniersity of Kentucky, Lexington, KY 49596, USA Received 23 January 1997; received in revised form 29 April 1997; accepted 22 May 1997 Abstract 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. © 1997 Elsevier Science B.V. Keywords: Win-stay/lose shift; Win-shift/lose-stay; Response 1. Introduction Rats show evidence of a natural predisposition to avoid recently visited locations whether they have been fed there (e.g. Dember and Fowler, 1958) or not (Timberlake and White, 1990). Such shift behavior does not appear to be characteristic of all species, however. For example, there is a prevalent notion that pigeons are predisposed to exhibit stay behavior. This hypothesis has been supported by findings that pigeons tend to perse- verate (Goodwin, 1967; Bond et al., 1981; Zentall et al., 1990). Feral pigeons, for example, habitu- ally forage in established patches (Goodwin, 1967) and possess excellent long-term memory for those locations (Levi, 1974). * Corresponding author. Tel.: +1 606 2574076; e-mail: zentall@pop.uky.edu 0376-6357/97/$17.00 © 1997 Elsevier Science B.V. All rights reserved. PII S0376-6357(97)00048-X