In an operant feature-positive discrimination, a response during a target stimulus (A) is reinforced when presented with a feature stimulus (X), but not when presented alone (XA+/A-). When the feature and the target occur simultaneously, direct control of the response by X is typically observed, whereas serial pairings produce occasion setting. The present experiment evaluated the effects of the temporal arrangement and spatial stability of the target in a spatial task with pigeons. On separate trials, Features W and X (display color) were simultaneously presented with Landmarks A and B (visual icons) displayed at the same location (out of a row of eight locations) across trials, and pecks at the same response box were reinforced on every trial (goal; simultaneous/static). On other trials, Features Y and Z preceded the onset of Landmarks C and D, which varied in their location across trials, and the reinforced response box was positioned relative to the landmark (serial/dynamic). Transfer tests compared responding to features and landmarks with similar (i.e., W:B, X:A, Y→D, Z→C; Test 1) or different (i.e., W:D, X:C, Y→B, Z→A; Test 2) training histories. Test 1 revealed evidence more consistent with occasion setting during serial/dynamic transfer, whereas evidence more consistent with direct control was observed during simultaneous/static transfer. Test 2 revealed asymmetries in transfer when the features and the targets from different training histories were tested. The results are largely consistent with past research, but testing within a spatial task allowed for an analysis of whether and where responses occurred. (PsycInfo Database Record (c) 2026 APA, all rights reserved).
Nerz et al. (Thu,) studied this question.