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 three 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 four and five 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.

Learning of hierarchical serial patterns emerges in infancy

“…In essence, it has frequently been noted that hierarchical patterns are characterized by a fundamental ambiguity in that they can potentially be represented in multiple ways (Fountain, ; Fountain & Doyle, ; Greeno & Simon, ; Jones, ). This issue has been most elegantly addressed by Fountain and colleagues (Fountain, ; Fountain & Doyle, ; Fountain & Rowan, ; Garlick et al, ; Muller & Fountain, ) who have provided compelling evidence for the existence of hierarchical versus associative representations in animals. For our purposes, the critical aspect is not the exact nature of the hierarchical representation, but rather that our findings demonstrate that infants can reliably discriminate hierarchically structured from non‐hierarchically (e.g., linear or associative) patterns.…”

“…In essence, it has frequently been noted that hierarchical patterns are characterized by a fundamental ambiguity in that they can potentially be represented in multiple ways (Fountain, 2008;Fountain & Doyle, 2011;Greeno & Simon, 1974;Jones, 1981). This issue has been most elegantly addressed by Fountain and colleagues (Fountain, 2008;Fountain & Doyle, 2011;Fountain & Rowan, 1995;Garlick et al, 2017;Muller & Fountain, 2016) who have provided compelling evidence for the existence of hierarchical versus associative representations in animals.…”

“…Classic research with these types of patterns has shown that human adults learn them as abstract rule-governed entities (Restle, 1972). More recent work with rats and pigeons has demonstrated that animals also can learn such abstract rule-governed entities (Fountain, 2008;Fountain & Doyle, 2011;Fountain & Rowan, 1995;Garlick et al, 2017;Muller & Fountain, 2016).…”

“…Humans and animals exhibit a remarkable ability to perceive, learn, produce, and remember hierarchically organized serial patterns (Fountain & Rowan, ; Garlick, Fountain, & Blaisdell, ; Greenfield, ; Lashley, ; Martin, ; Restle, ; Restle & Burnside, ). These types of patterns are characterized by the rule‐governed, recursive embedding of lower‐level units (chunks) into higher‐level units.…”

Evidence for Object-Place binding in pigeons in a sequence-learning procedure

“…Prior studies have shown that pigeons will naturally (i.e., without explicit reinforcement) encode sequences of locations (Froehlich et al, 2004;Herbranson & Stanton, 2011;Herbranson, Xi, & Trinh, 2014), though they can also learn sequences through reinforcement (Garlick, Fountain, & Blaisdell, 2016). Perhaps prior studies that failed to show lasting feature binding resulted from procedures that failed to sufficiently increase the salience of, and thereby attention to feature conjunctions.…”