Light Reinforcement in the Rat: The Effects of Continuous and Discontinuous Periods of Apparatus Familiarization

Abstract

The effects of continuous and discontinuous periods of apparatus familiarization on light reinforcement in rats were examined. A previous finding that the light reinforcement effect is greater with longer pretest periods in the dark box was confirmed by comparing 270 min and 30 min periods in the box prior to testing 24 h later. A discontinuous period of 9 daily 30 min sessions, however, produced a bigger effect than the 270 min continuous period. It was concluded that the degree of familiarization with the apparatus is a more important factor than length of time per se in the dark in determining the effectiveness of light as a reinforcer.

Effects of mere exposure on preferences in nonhuman mammals.

“…However, Robinson's (1959) negative finding and the apparent familiarity artifact observed by D. I. Williams and Lowe (1972) suggest that the satiation effect may be slightly less reliable than the mere exposure effect. Though it might plausibly be predicted that longer intervals between preexposure and test would increase preference for the preexposed level of illumination, little evidence can be found to support that prediction.…”

“…Williams and Lowe (1970). Another study by Williams and Lowe (1972) suggests that some positive findings may be artifactual. They found that the reinforcing effect of dim light was greater if the rats had spent 270 min.…”

Rats’ novel object interaction as a measure of environmental familiarity

“…Whether this prevalent form of learning is treated explicitly in an experiment with a habituation phase, or is merely ignored, varies widely in the literature. Although environmental familiarization in many conditioning situations likely has little to no effect, there are published examples of differences in familiarization affecting learning (Besheer and Bevins, 2000, Harrison and Isaac, 1984, Rowe et al, 1998, Williams et al, 1972and Wilson et al, 2004. Given the prevalence of environmental familiarization as a learning process, and its potential infl uence on acquisition and/or performance in some learning experiments, there is surprisingly little systematic behavioral research on factors affecting familiarization.…”

“…In contrast, other conditioning protocols simply start training with the implicit or explicit assumption that the animal will become familiar with the experimental environment and that this familiarization process will not signifi cantly impact the learning process(es) of interest. Although this assumption is likely true for a great number of experiments, there are several published examples of differences in environmental familiarization affecting learning (e.g., Besheer and Bevins, 2000, Harrison and Isaac, 1984, Rowe et al, 1998, Williams et al, 1972and Wilson et al, 2004. In the 1950s and 60s, there was a surge of behavioral research on environmental familiarization and associated processes.…”

Nicotine Self-Administration in Animals: A Reevaluation

“…In addition to these two crucial alternative mechanisms, there is another factor that may have influenced the results of Goldberg, Spealman, and Goldberg's study. Research conducted more than two decades ago has established that rats in a stimulus-free environment are willing to work for the light stimulus itself (e.g., Williams and Lowe, 1972;Myslobodsky, 1976;Harrington, 1979). While there is no direct evidence that monkeys will acquire level pressing with a light reward, it is a possibility that should be considered in interpreting the results of this study, especially in light of the poor reliability of the nicotine self-administration paradigm.…”