Association for Behavior Analysis International

Recent empirical and conceptual developments (e.g., Wasserman & Frank, 2005; Urcuioli, 2008) have suggested that the failure to observe derived relational responding in nonhuman subjects is the result of irrelevant stimulus properties such as the spatial location of the stimuli gaining control over the response. Procedures that preclude the development of control by irrelevant features have begun to produce reliable evidence of associative symmetry in pigeons. This symposium brings together presentations from four different laboratories investigating derived relational responding with nonhuman subjects using this procedure. Campos & Debert present data on pigeons working with compound visual stimuli and ask whether the resulting performances are conditional discriminations. Vaidya & Stancato present some data on stimulus-parameter manipulations and their effects on pigeons' acquisition of baseline relations and performance on tests for associative symmetry. Bruce, Prichard, & Galizio report presents data on rats' acquisition of baseline relations and emergent symmetry using olfactory stimuli. Finally, Swisher & Urcuioli present some data on stimulus locations and their role in the emergence of associative symmetry in pigeons' go/no-go performances.

A go/no-go procedure with compound stimuli investigates stimulus class formation in tests that resemble the typical tests conducted with the matching-to-sample procedure. This experiment investigated stimulus class formation using a transfer of function test after training in a go/no-go procedure with compound stimuli. Six pigeons were trained to respond to A1B1, A2B2, B1C1, and B2C2 and refrain from responding to A1B2, A2B1, B1C2, and B2C1. Subsequently, subjects were trained to respond in DRL 3 s, a lower response rate, to A1 and in FR20, a higher response rate, to A2. Tests presented B1, C1, B2, and C2 to verify if subjects would show a lower response rate to B1 and C1 and a higher response rate to B2 and C2. Results showed a different response pattern for each stimulus and subject. Neither pattern was consistent with stimulus class formation. Stimulus class formation was not verified using transfer of function tests.

The Go, No-Go procedure has recently attracted attention for its use in establishing symmetrical relations/responding in pigeons (Frank and Wasserman, 2005, Urcuiolli, 2008). In our attempts to utilize the Go, No-Go procedure to systematically replicate Urcuioli (2008), we found evidence of selective attending to stimuli that possibly precluded contact with the relevant feature of the stimuli. As a result, components of the stimuli were systematically manipulated to bring pigeons responding in line with the experimenter defined baseline conditional relations. In particular, we began presenting the stimuli over the entire display as opposed to on small "keys". Our results suggest rapid acquisition of the conditional relations with both forms and colors. It remains to be seen if the performance on probe trials will meet the definition of emergent symmetry. The results will be discussed in terms of cross modal sample and comparison stimuli and the role that the procedural features in the establishment of baseline conditional discriminations and derived symmetrical relations.

Most studies of emergent symmetry in nonhumans have yielded negative results. However, symmetry has been demonstrated in pigeons using visual stimuli in a successive discrimination procedure (Frank & Wasserman, 2005; Urcuioli, 2008 and subsequent studies). We attempted to replicate Urcuioli's (2008) study in rats using scents as stimuli and comparisons in an automated olfactometer. Rats were trained on identity and arbitrary conditional discriminations and after meeting criterion, were tested for symmetry. Results failed to show evidence of emergent symmetry. A second group of rats was trained exclusively on identity relations using the same successive discrimination procedures and showed evidence of generalized identity matching.

Two previous experiments demonstrated symmetry in pigeons after concurrent training on hue-form symbolic, hue identity, and form identity go/no-go matching even with samples presented in one spatial location (center key) and comparisons in a different spatial location (left key). In the present study, one group of pigeons (Experimental) was trained using these same baseline contingencies. A second, control group received similar training except for its form identity task in which both samples and comparisons appeared in the same spatial location (center key). Subsequent symmetry probe trials were the same for both groups, consisting of center-key form samples and left-key hue comparisons. As predicted by Urcuioli's (2008) theory of stimulus-class formation, three of four pigeons in the Experimental group showed symmetry. Contrary to theory, however, so did two of four Control pigeons, although follow-up studies question whether that result might be replicable.