Transfer between Pavlovian facilitators and instrumental discriminative stimuli

Abstract

Two experiments assessed the degree to which Pavlovian facilitators were interchangeable with instrumental discriminative stimuli (SdS). In Experiment I, rats were trained in a Pavlovian paradigm in which one stimulus (i.e., a facilitator) signaled the reinforcement of another stimulus (i.e., a target). Next, the rats were given instrumental discrimination training in which an s-signaled the reinforcement of barpressing. A transfer test then assessed the capacity of the Pavlovian facilitator to promote barpressing. The results showed that the facilitator promoted significant barpressing, both when it was presented alone and when it was presented in compound with the Sd. Reliable transfer was not obtained with a "pseudofacilitator" control stimulus that, during training, was uninformative about the reinforcement of its target. Experiment 2 showed that a stimulus trained as an instrumental Sdreliably augmented responding to a stimulus previously trained as a target in a Pavlovian facilitation paradigm. A "pseudo-S?" that, during training, was uninformative about the reinforcement ofbarpressing failed to promote such transfer. These results show that Pavlovian facilitators and instrumental SdS are interchangeable to a significant degree, and suggest that facilitators and SdS may act via similar mechanisms.There has been considerable recent interest in Pavlovian procedures in which one stimulus (B) is informative about the relationship between another stimulus (A) and the unconditioned stimulus (US). For instance, Holland (1983) and Rescorla (1985) have studied paradigms in which A is reinforced when preceded by B but nonreinforced when presented alone. Animals given this A-, BA+ treatment commonly respond more to A accompanied by B than to A presented alone. A similar outcome is also obtained when the A-, BA+ treatment is augmented by separate nonreinforced presentations of B (Davidson & Rescorla, 1986;Ross & Holland, 1982). Ross and Holland (1982) have described B as "setting the occasion" for the reinforcement of A. Rescorla (1985) has described B as a "facilitator" of responding to A.These procedures are of interest not only for what they might reveal about Pavlovian conditioning, but also for their relationship to certain instrumental learning paradigms. As Holland (1983) and Rescorla (1985) have pointed out, there is a formal similarity between the B stimulus in these Pavlovian paradigms and the discriminative stimulus (Sd) in instrumental training paradigms. In the Pavlovian paradigms, only the joint occurrence of A with B is followed by reinforcement; neither A nor B alone is reinforced. Similarly, in operant discriminations, only

Ethnomathematics in Ethiopia: Futile or Fertile for Mathematics Education?

“…In order to put the role of ethnomathematics into effect, curriculum experts should at least be aware of its relevance, in ensuring effective teaching and meaningful learning in the mathematics classroom and thus, should offer some space for accommodation. According to Matang (2002, p.35 Of course, these problems that brought to the class by the students and that incorporated in the curriculum by the experts, as Davis (1996) as well as Boaler (1993) have suggested, should be 'novel' that magnify the role of ethnomathematics in providing context-rich problems that enhance students' problem solving strategies and offer much opportunity in providing the necessary contextual meaning to many abstract mathematical concepts.…”

“…To attain this above objective, Davis (1996);and Boaler (1993) suggest mathematics leaning in context-rich situations. Both of these authors argue that students should spend their time solving novel or context-rich problems open to reflection after the solutions to the problems are invented.…”

“…The use of context-rich problems from students' cultural background or related history is supported educationally. For instance, Davis (1996) suggests focusing on such 'novel' mathematics problems because students would come to these problems without prior instruction in how to solve them. For Davis, it would be the experience of inventing a way to deal with such problems that would enable the students to learn what mathematics really is, and what it means to "do mathematics".…”

Modulatory mechanisms in Pavlovian conditioning

“…Holland (1989a, described in detail in the next section) has provided data consistent with this conclusion using the observational preparation with rats. Two experiments by Davidson et al (1988), who used rat subjects, provide further evidence against a specific response as the locus of modulatory action. They investigated the interchangeability of Pavlovian modulators and stimuli trained as instrumental discriminative stimuli (SOs).…”

“…With each procedure, the stimuli are at least theoretically capable of providing in-formation about reinforcement of the other stimulus. This viewpoint is perhaps best exemplified by the use of the pseudofacilitator, or AB+,B+, treatment as a control for positive modulation acquired through AB+,B-discrimination training (see, e.g., Davidson et al, 1988;Davidson & Rescorla, 1986;Holland, 1986b;Rescorla, 1985;Wilson & Pearce, 1989). Although the pseudofacilitator may not control accurately for the modulator's excitation or for the associative status of the modulator's target, the pseudo facilitator and modulator are paired an equal number oftimes with a target and with the US.…”