Generalization gradients following training on a symbolic matching-to-sample task

Stimulus Control of Pavlovian Facilitation

“…That is, generalization testing produced either decremental or flat gradients depending on the presence or absence of the facilitator. The recent findings of Bowers and Richards (1986) from a second group of birds treated similarly to Group FA (except for the instrumental contingency) are of considerable interest in relation to this result. In their successive matchingto-sample task, responding to a black vertical line on white background produced food if the previous sample was a blue light (BV+) but not if the sample had been red (RV-).…”

“…The facilitator's failure to control responding also conflicts with control gradients obtained following training on operant conditional discriminations. Using procedures very similar to Pavlovian facilitation except for the presence of instrumental contingencies, Bowers and Richards (1986) obtained line-orientation gradients following successive (one key) symbolic matching-to-sample training. Specifically, one group of pigeons received food for responding to a red comparison stimulus if a previously presented stimulus (sample) had been a black vertical line on a white background (VR+) but not if the previous sample had been a white light (WR-).…”

“…In the foregoing discussion, it was suggested that dimensional control by the Pavlovian facilitator failed to develop because the lines' orientation was overshadowed by some feature of the visual stimulus. Overshadowing seemed likely because an explicit B -(any stimulus preceding A-in the B -A+, A-discrimination) was absent from the discrimination procedure, unlike either operant feature-positive (Hearst, 1969;Honig et al, 1963) or conditional (Bowers & Richards, 1986;Richards, 1979) discriminations in which an explicit Swas present and stimulus control was established. To test the possibility that the absence of an explicit Bwas responsible for the flat control gradients of Group FB, the primary objective of Experiment 2 was to assess stimulus control following a Pavlovian feature-positive serial discrimination in which an explicit stimulus precedes A-.…”

Transfer testing after serial feature-ambiguous discrimination in Pavlovian keypeck conditioning

“…All of these features were circular white-and-black patterns projected on the same position of the key. Thus, their physical similarity would permit stimulus generalization (see Parker, Serdikoff, Kaminski, and Critchfield, 1991, for generalization of feature stimulus control; see also Bowers & Richards, 1986).…”

Operant generalization in quail neonates after intradimensional training: Distinguishing positive and negative reinforcement

“…Standard S+/S− interdimensional training provides the classic examples (e.g., Bowers and Richards, 1986; Jenkins and Harrison, 1962). In his review, Rilling (1977) suggested that inhibitory gradients might occur only at the S− after appropriate interdimensional training; he did not anticipate the existence of intradimensional inhibitory gradients.…”