AUTOSHAPING, RANDOM CONTROL, AND OMISSION TRAINING IN THE RAT¹

Abstract

The role of the stimulus-reinforcer contingency in the development and maintenance of lever contact responding was studied in hooded rats. In Experiment I, three groups of experimentally naive rats were trained either on autoshaping, omission training, or a random-control procedure. Subjects trained by the autoshaping procedure responded more consistently than did either random-control or omission-trained subjects. The probability of at least one lever contact per trial was slightly higher in subjects trained by the omission procedure than by the random-control procedure. However, these differences were not maintained during extended training, nor were they evident in total lever-contact frequencies. When omission and random-control subjects were switched to the autoshaping condition, lever contacts increased in all animals, but a pronounced retardation was observed in omission subjects relative to the random-control subjects. In addition, subjects originally exposed to the random-control procedure, and later switched to autoshaping, acquired more rapidly than naive subjects that were exposed only on the autoshaping procedure. In Experiment II, subjects originally trained by an autoshaping procedure were exposed either to an omission, a random-control, or an extinction procedure. No differences were observed among the groups either in the rate at which lever contacts decreased or in the frequency of lever contacts at the end of training. These data implicate prior experience in the interpretation of omission-training effects and suggest limitations in the influence of stimulus-reinforcer relations in autoshaping.

An omission procedure reorganizes the microstructure of sign-tracking while preserving incentive salience

“…Thus 60% of the acquired sign-tracking CR persisted despite the omission schedule, and the persistence was similar to Controls. This suggests that the CS+ retained much of its motivational value and that its expression in behavior was highly flexible.Although Locurto et al (1976) observed differences in response topography between rats placed on sign-tracking and omission schedules, these differences were not quantified. Based on a near-full reduction in lever contacts in their study, Locurto et al (1976) argued that omission training was ineffective at maintaining responding to the lever.…”

“…Sign-tracking is a key model for studying behavioral and neural mechanisms of normal and excessive motivational attraction to reward-paired stimuli (Lajoie and Bindra 1976;Berridge 2004;Tomie et al 2008;Flagel et al 2010;Robinson and Berridge 2013;Huys et al 2014;Robinson et al 2014). Negative automaintenance, in which a lever press cancels reward, has been used to show that sign-tracking can be markedly sensitive to instrumental contingency changes (Williams and Williams 1969;Stiers and Silberberg 1974;Locurto et al 1976), suggesting a sensitivity to response-reward associations (Skinner 1992). For example, Locurto et al (1976) have found that lever contacts after sign-tracking are markedly reduced in rats moved to an omission schedule, with similar rates of lever contacts compared with rats exposed to extinction or random cue/reward delivery.…”

“…Negative automaintenance, in which a lever press cancels reward, has been used to show that sign-tracking can be markedly sensitive to instrumental contingency changes (Williams and Williams 1969;Stiers and Silberberg 1974;Locurto et al 1976), suggesting a sensitivity to response-reward associations (Skinner 1992). For example, Locurto et al (1976) have found that lever contacts after sign-tracking are markedly reduced in rats moved to an omission schedule, with similar rates of lever contacts compared with rats exposed to extinction or random cue/reward delivery.…”

“…Indeed, sign-tracking components can be expressed differently in sign-tracking and negative automaintenance conditions (Schwartz and Williams 1972b;Stiers and Silberberg 1974;Locurto et al 1976;Davey et al 1981), as well as when motivational processes are enhanced by brain manipulations (Mahler and Berridge 2009). Thus, we evaluated how signtracking may persist through differential expression of CRs.…”

Polydipsia and autoshaping: Drinking and leverpressing as substitutes for eating

“…Peterson maintained his rats at 80070 of their normal body weights by giving them supplemental feedings of 5 to 10 g daily. They had free access to water in the home cage, but no water in the test chamber-the standard practice of subsequent experiments on autoshaping with food delivery as the signaled event (Atnip, 1977;Locurto, Terrace, & Gibbon, 1976;Stiers & Silberberg, 1974).…”