Pavlovian appetitive contingencies and approach versus withdrawal to conditioned stimuli in pigeons.

Abstract
Investigated the directed skeletal movements of 21 female White Carneaux pigeons toward signals of food or no food in 3 experiments. Ss approached and pecked an illuminated key that was positively correlated with food delivery, and positioned themselves relatively far from an illuminated key that was negatively correlated with food delivery. Key illuminations alone, random presentations of key illuminations and food, and backward pairings of key illuminations and food did not produce keypecking or consistent approach-withdrawal. Therefore, directed skeletal behavior-often believed to be conditioned and maintained primarily or exclusively by operant procedures-also emerges on Pavlovian procedures. Several kinds of alternative explanations (e.g., conditioned reinforcement effects, and stimulus substitution) for these phenomena are considered, and some potential implications for operant discrimination learning are briefly explored. (17 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved)