Schedule‐induced Defecation

Abstract

Excessive defecation, typically considered to be a concomitant of stress, was experimentally induced or eliminated under specific schedules of positive reinforcement of lever pressing by rats. The schedules were, by and large, those under which polydipsia is typically induced. In the first of three experiments, rats under fixed-interval 32-second schedules and variable interval 32-second schedules for food and water reinforcers defecated profusely, but not under fixed-interval one-second schedules or other small interval schedules. Somewhat higher rates of defecation were observed on variable interval 32-second schedules than on fixed-interval 32-second schedules. In a second experiment, fixed-ratio schedules were used, some of which resulted in responding such that reinforcement densities were similar to those on the interval schedules that induced defecation. Defecation was not systematically induced by these ratio schedules. In a third experiment, fixed-time schedules of food presentations were utilized. High rates of defecation were induced comparable to those induced by interval schedules of the same time parameter. No other behavior commonly termed "emotional" was observed in any of these experiments.

Wheel running induced by intermittent food schedules

“…In 1961, Falk observed that exposure of food-deprived rats to intermittent food reinforcement schedules, with free access to a bottle containing water in the experimental chambers, caused the development of excessive drinking (schedule-induced polydipsia, SIP) unrelated to physiological needs or apparent behavior regulation. Other similar behavioral patterns were later studied, such as wheel running (Levitsky & Collier, 1968), air licking (Mendelson & Chillag, 1970), wood chewing (Roper & Crossland, 1982), pica (Villareal, 1967), aggression (Looney & Cohen, 1982), escape (Brown & Flory, 1972), defecation (Rayfield, Segal & Goldiamond, 1982) and a long list of other activities (see reviews by Falk, 1977;Pellón, 1990), all in theory being modulated by the degree of intermittency in the reinforcement. These behavioral patterns have been called adjunctive behaviors (or schedule-induced behaviors) (Falk, 1971;Roper & Posadas-Andrews, 1981;Staddon, 1977;Timberlake, Wahl & King, 1982;Wetherington, 1982), and are characterized primarily by meeting the criteria of significantly higher response rates when exposed to intermittent reinforcement (albeit without an explicitly arranged contingency between behavior and reinforcer occurrence) which are usually observed following the reinforcer in the form of an inverted-U throughout the inter-reinforcement interval.…”

Food‐deprivation Effects on Punished Schedule‐induced Drinking in Rats

“…In addition to rats, schedule-induced polydipsia also develops in mice (Palfai, Kutscher, & Symons, 1971), guinea pigs (Porter, Sozer, & Moeschl, 1977), gerbils (Porter & Bryant, 1978), and rhesus monkeys (Allen & Kenshalo, 1976). Other induced or adjunctive patterns of behavior have been observed, including aggression in pigeons (Looney & Cohen, 1982, for a review), defecation in rats (Rayfield, Segal, & Goldiamond, 1982), and the ingestion of nonnutritive substances in monkeys (Villareal, 1967). Schedule-induced polydipsia and other adjunctive behavior have received much empirical and theoretical attention (see reviews by Falk, 1977;Staddon, 1977;Wetherington, 1982), but our understanding of these phenomena is still incomplete (see Reid & Staddon, 1990).…”

Development of bingeing in rats altered by a small operant requirement

“…For example intermittent (60 s) pellet presentations in an operant chamber to food-deprived rats, whether response independent (Fixed Time) or response dependent (Fixed Interval), generate several classes of excessive behavior that have been labeled “schedule-induced” or “adjunctive”. Some of the earliest identified classes of behaviors included polydipsia, [28], air-licking [29] wheel running [30,31], wood chewing [32], and defecation [33] among others. This literature is large and several interpretations have been presented to account for the occurrences of excessive behaviors in the context in which they occur, but without any resolution [34,35].…”