Relational discrimination by pigeons in a go/no-go procedure with compound stimuli: a methodological note

Abstract

A go/no-go procedure with compound stimuli typically establishes emergent behavior that parallels in structure and typical outcome that of conventional tests for symmetric, transitive, and equivalence relations in normally capable adults. The present study employed a go/no-go compound stimulus procedure with pigeons. During training, pecks to two-component compounds A1B1, A2B2, B1C1, and B2C2 were followed by food. Pecks to compounds A1B2, A2B1, B1C2, and B2C1 re-started the 30-s stimulus presentation interval. The absence of pecking to those compounds for 30 s ended the trial. Subsequent tests presented these components in new spatial arrangements and/or in recombinative compounds that together corresponded to conventional tests of symmetry, transitivity, and equivalence: B1A1, B2A2, C1B1, C2B2, A1C1, A2C2, C1A1, C2A2 vs. B1A2, B2A1, C1B2, C2B1, A1C2, A2C1, C1A2, C2A1 (positive vs. negative instances of symmetric, transitive, and equivalence relations). On tests for symmetric relations, all pigeons behaved in a manner consistent with training on both positive instances (i.e., by responding) and on negative instances (i.e., by not responding). By contrast, the pigeons' behavior on tests for transitivity and equivalence was inconsistent with baseline training, thus failing to show the recombinative discrimination performance that is typical of normally capable humans when trained and tested using the go/no-go procedure with compound stimuli.

Keywords: Go/no-go procedure; compound stimuli; key peck; pigeons; stimulus equivalence.

Fig 1

Illustration of the compound stimuli presented during the experimental phases and their designations. R indicates red; B, blue; O, orange; G, green; Y, yellow and P, purple.

Fig 2

Discriminative ratio for each session during AB training, BC training and AB and BC training for Subjects P9, P10, P11 and P21.

Fig 3

Number of responses to baseline and symmetry test compound stimuli during symmetry test for Subjects P9, P10, P11 and P21. The left portion presents the baseline compounds. The right portion presents the symmetry test compounds. Black columns refer to “related” compounds and white columns refer to “not-related” compounds.

Fig 4

Number of responses to baseline and transitivity test compound stimuli during transitivity tests for Subjects P9, P10, P11 and P21. The left portion presents the results of Session 1 and the right portion presents the results of Session 2. In each graph, the left portion presents the baseline compounds and the right portion presents the transitivity test compounds. Black columns refer to “related” compounds and white columns refer to “not-related” compounds.

Fig 5

Number of responses to baseline and equivalence test compound stimuli during equivalence test for Subjects P9, P10, P11 and P21. The left portion presents the results of Session 1 and the right portion presents the results of Session 2. In each graph, the left portion presents the baseline compounds and the right portion presents the equivalence test compounds. Black columns refer to “related” compounds and white columns refer to “not-related” compounds. Subject P11's baseline data from the first equivalence test session are not presented here because, as the text notes, transitivity and equivalence tests were conducted inadvertently in the same session. Therefore, baseline data are presented only in Figure 4.