In Experiment I, 12 rats were exposed to an FT 60 schedule of food reinforcement, followed either by extinction or by a massed-food control condition, in the presence of a wood block. In 9 rats, wood-chewing behavior increased systematically during the FT 60 condition and declined again during extinction or massed food, while the other 3 rats showed virtually no chewing behavior at any stage of the experiment. In Experiment 2, frequency and bout duration of wood-ehewing under an FT 60 schedule of food reinforcement declined as body weight increased, in 7 rats. We conclude that wood-chewing qualifies as a schedule-induced behavior, and that it resembles schedule-induced drinking in its dependence on body weight. Unlike drinking, however, induced chewing occupied the middle region of the 60-sec interreinforcement interval, declined markedly within the session, and showed considerable within-and between-subject variability. Falk (1961) found that when rats were allowed to obtain food according to an intermittent (VI 60-sec) schedule of food reinforcement, and were given concurrent free access to a water bottle, they developed the habit of drinking immediately after eating each food pellet. Because the rats' cumulative intake of water under these circumstances was abnormally large, Falk referred to the postpellet drinking as "schedule-induced polydipsia." Schedule-induced polydipsia has been extensively studied in the subsequent two decades, but its cause remains obscure: numerous explanations have been offered, but none has proved satisfactory (see reviews by Falk, 1971;Segal, 1972;Staddon, 1977).Explanations of schedule-induced drinking have been of two distinct types, which may be termed "thirst" explanations and "general activation" explanations, respectively (Roper, 1980b). "Thirst" explanations hold that intermittent presentation of food exerts a specific facilitatory effect on drinking, for example by stimulating oral dehydration receptors (Stein, 1964)or by causing a fall in blood glucose level (Freed, Zec, & Mendelson, 1977). "General activation" explanations, on the other hand, hold that intermittent presentation of food exerts a more or less general facilitatory effect on nonfeeding behaviors, via a state or process termed frustration (e.g., Thomka & Rosellini, 1975), arousal (e.g., Killeen, 1975; Brett & Levine, 1979), general motor excitability (Wayner, 1974), or stress (e.g., Wallace & Singer, 1976).At present most investigators seem to favor a gen- eral activation account, on the grounds that schedule induction extends across a variety of species, reinforcers, and behaviors. But whether one regards induction as a general phenomenon depends on the stringency of one's definition. The term "scheduleinduced" is commonly applied to any activity that occurs during interreinforcement intervals, regardless of its frequency of occurrence, whereas a stringent demonstration of induction requires that the behavior in question be shown to occur more frequently in association with a schedule of reinforcement than ...

Through the administration of self-report surveys, this study examined the relationships among a) parenting styles, b) family structure, c) academic achievement, d) birth order, e) gender, and f) humor on the initial personal-emotional, social, academic, and commitment to college adjustment among 257 first-quarter college freshmen. Multiple regression models demonstrated that humor, academic achievement, and authoritative parenting were positively related to students' college adjustment. Implications were drawn for post-secondary educational institutions as well as parents.

In Experiment I, rats were allowed to acquire either schedule-induced drinking or scheduleinduced wood-chewing behavior under a fixed-interval (FI) 60-sec schedule of food reinforcement, following which food was omitted from 20% and then 50% of interreinforcement intervals. Omission of food severely disrupted induced drinking but had relatively little effect on induced wood-chewing. Experiment 2 investigated wood-chewing as a function of reinforcement rate, using a range of FI schedules from 5 to 180 sec in duration. Both the amount of chewing per session and the relative time spent chewing were bitonica1ly related to reinforcement rate. In Experiment 3, schedule-induced chewing that had been acquired under a response-dependent schedule was found to persist under a response-independent schedule. Induced wood-chewing resembles other induced behaviors in important respects, but quantitative differences are also apparent.Falk (1961) showed that when rats were allowed to earn food pellets intermittently, in the presence of a water source, they developed the habit of drinking a small amount of water within each interpellet interval. Because it dramatically enhances the rat's water intake, this type of drinking has become known as "schedule-induced polydipsia," or SIP. Two decades of research have revealed SIP to be an extraordinarily reliable effect, by behavioral standards, and have produced a wealth of experimental results and of conflicting theoretical accounts (see reviews by Falk, 1971, and Staddon, 1977. Nevertheless, no satisfactory explanation of the rat's enhanced drinking under intermittent schedules of food availability has yet emerged.We have chosen to address the problem of SIP obliquely, by asking whether the phenomenon of schedule induction extends to activities other than drinking, to reinforcers other than food, and to species other than the rat. In this way, we hope to determine the extent to which SIP depends on special characteristics of the relationship between eating and drinking in the rat, as opposed to reflecting the operation of more general principles. We have recently confirmed that wood-chewing can occur as a schedule-induced behavior in rats when food is intermittently available, and have shown that induced wood-chewing (like SIP) is inversely related to level of food deprivation (Roper & Crossland, 1982). This finding supports the idea that schedule indueWe thank the SRC for financial support. Reprints may be obtained from: T. J. Roper, School of Biology, University of Sussex, Brighton BNI 900, England. 35 tion is a general phenomenon (for a critical review of other relevant evidence, see Roper, 1981). On the other hand, schedule-induced wood-chewing has so far proved relatively variable in its rate and probability of acquisition, and it differs from SIP in the precise temporal location of the behavior within the interfood interval (Roper & Crossland, 1981). Thus, induced activities other than drinking may not resemble SIP in all respects.In this paper, we pursue the analogy between...

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