Serial pattern learning in pigeons: Rule-based or associative?

Abstract

Extensive research has documented evidence for rule learning in sequential behavior tasks in both rats and humans. We adapted the 2-choice serial multiple choice (SMC) task developed for use with rats (Fountain & Rowan, 1995a) to study sequence behavior in pigeons. Pigeons were presented with 8 disks arranged in a circular array on a touchscreen, and pecking to an illuminated disk could lead to reward. Correct responding consisted of serial patterns involving "run" chunks of 3 elements (123 234, etc.). Some pigeons experienced a violation of the chunk rule in the final chunk. Unlike rats, pigeons made fewer errors on violation chunks than run chunks, suggesting the use of low-level cues to guide choices. Removal of low-level cues and increasing the number of simultaneously illuminated disks to an 8-choice SMC task resulted in more errors on the violation chunk. Pigeons were able to use the rule when the array of disks was contracted or expanded, and when chunk length was extended to 4 and 5 elements, but not when disks were removed from or added to the array. Pigeons were also able to abstract structure from a "trill" pattern (121 232 etc.), as shown by high error rates on a violation trial. These results suggest that pigeons, like rats and humans, can abstract sequence structure, but do so primarily in the absence of specific low-level feature-based information. (PsycINFO Database Record