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 co mpared using a two-alternative conditional discrimination for which th e number of trials involving each of the task components could be prec isely 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-shif t). Another group was rewarded for pecking the location just pecked if those pecks were not followed by food and for pecking the other locat ion if those pecks were followed by food (win-shift/lose-stay). With i ncreasing delay to comparison choice, pigeons were more accurate on tr ials when initial pecking was followed by the absence of food than by food (Experiment 1). However, when hypothesized overt response mediati on was discouraged (Experiment 2), a win-stay superiority effect emerg ed with increasing delay to comparison choice. Thus, unlike rats, pige ons may be somewhat predisposed to repeat a response to a location to which responses have been previously rewarded. (C) 1997 Elsevier Scien ce B.V.