Proprioceptive sample stimuli and associative symmetry in pigeons

Marco Alexandre Barbosa Vasconcelos, Purdue University

Abstract

Symmetry (the ability to match B to A after learning to match A to B) has been difficult to observe in nonhumans. This difficulty led to the appreciation that a stimulus to us is quite different from the functional stimulus for other animals. Animals seem to perceive stimuli as a conjunction of visual, spatial, and temporal characteristics and when such characteristics are controlled symmetry does emerge in nonhumans (cf. Frank & Wasserman, 2005; Urcuioli, in press). Recently, however, Garcia and Benjumea (2006) reported symmetry in pigeons without controlling for temporal order. In their experiments, the sample was presented at one of two different spatial locations on each training trial and, at test, the same comparison was presented at both those locations at trial onset. This study explored their paradigm and the ingredients for their success. The Preliminary Experiment and Experiment 1 were designed to replicate their findings and to examine different symmetry measures using their procedure. Both experiments returned evidence for symmetry using Garcia and Benjumea’s test and a latency-based test. Experiment 1 also returned evidence for symmetry using a consistent versus inconsistent manipulation. Experiment 2a tested the claim that the functional samples in their procedure are proprioceptive rather than exteroceptive by requiring pigeons to peck 20 times to a stimulus presented on one side key and to space two pecks at least 3 s apart to the same stimulus presented on the other side key. Subsequent tests revealed that the pattern-choice relations learned in training were not symmetrical. Experiment 2b showed that comparison choice in Experiment 2a had been cued by sample location rather than by the differential sample behaviors conditioned to each side key. Although further research is needed, it seems that the functional samples in this task are exteroceptive rather than proprioceptive. Experiment 3 adapted the Garcia and Benjumea procedure to test for symmetry in a successive matching task in order to evaluate their contention that simultaneous presentation of at least two comparisons is necessary for the emergence of symmetry. Contrary to their prediction, evidence for symmetry was obtained. The results of these experiments suggest that language is not a prerequisite for symmetry and that symmetry might simply result from the reinforcement contingencies of training.

Degree

Ph.D.

Advisors

Urcuioli, Purdue University.

Subject Area

Experimental psychology|Cognitive psychology

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