Conditions Producing Psychogenic Polydipsia in Animals*

Abstract

A brief summary of the first report (Falk, 1961a) on schedule-induced polydipsia will suffice to introduce this phenomenon. Fourteen normal rats were maintained at 70-80 percent of their free-feeding body weight by limiting their intake of food. The animals earned most of their daily food ration by bar-pressing on a variable-interval one-minute (VI 1 min) schedule for 45-mg Noyes food pellets during 3.17-hour daily experimental sessions. On this schedule, a barpress is reinforced by a food pellet at varying times from a previous reinforcement (from a few seconds to two minutes), the average interreinforcement time being one minute. Each animal performed in a sound-attenuated box, with the automatic control and recording equipment in an adjoining room. No external environmental cue informed the animal exactly when a bar-press would yield a pellet. At the end of each daily session, the animal was returned to its home cage and given any food supplement necessary to maintain body weight at the value selected.Water was always available. During the session licks from a calibrated water reservoir were recorded electronically. In the home cage, any water drunk from a calibrated animal drinking tube between sessions was measured.On this schedule a typical behavior pattern rapidly developed. After earning a food pellet, the rat would consume it and drink about 0.5 ml of water. During the 3.17-hour session, intake averaged 92.5 ml, or 3.43 times the preexperimental, 24-hour water intake level. Between sessions, although water was available, intake averaged less than 1 ml.Such a phenomenon is strange and unprecedented, for the animals are drinking approximately one-half their body weight in a few hours. Water deprivation, heat stress, or osmotic-loading techniques do not approach comparable stimulation of water intake. Under normal laboratory maintenance conditions, daily water intake levels remain rather constant, and even strong facilitating stimuli induce only moderate increases.The evidence will be examined to determine whether this polydipsic phenomenon can be explained either on physiological grounds or with respect to simple behavioral considerations. The variables of which the polydipsia is a function will be summarized as far as these are known at present. A theoretical explanation in terms of adjunctive behavior will be given, and methodological implications and cautions for thirst research attempted. PHYSIOLOGICAL CONSIDERATIONS Food Deprivation and Water IntakeThe sole, unusual physiological condition of existence for these animals is their maintenance at 80 percent of free-feeding weight by limiting food intake. How-* Annals New York Academy of Sciences ever, food deprivation decreases, rather than increases, water intake. I found that animals maintained at 80 percent body weight in their home cages drank less water than when allowed unlimited access to food (Falk, 1964, p. 98). Strominger (1946 reported similar results, as has Kutcher (1967). Recently, I allowed animals held at 80 percent body weight to consum...

Ubiquity of Schedule-Induced Polydipsia

“…Earlier studies, including those of Falk (1969) and Keehn and Colotla (1971), have also shown suppression of schedule-induced drinking by competing behavior. In both of these studies, the normal post-reinforcement drinking induced by a time-based food-reinforcement schedule was inhibited by making food-reinforced behavior highly probable after spaced pellet presentations.…”

Periodic water, interwater interval, and adjunctive behavior in a 24-hour multiresponse environment

“…Another difficulty is the nature of the relationship between reward frequency and adjunctive responding. Although a bitonic relationship between reward frequency and total adjunctive responding is well supported (e.g, Falk, 1969Falk, , 1971Falk, ,1977Wetherington, 1982), recent investigators have focused on a direct relationship between reThis research was supported by NIMH Grant MH37892. The authors wish to thankHillary Case for her extensive help with data analysis and Andy Delamater for his comments.…”

Comportamento adjunto: controvérsias e contribuições teóricas

“…Esse fenômeno chamou a atenção de Falk sugerindo-lhe tratar-se de uma polidipsia (beber em excesso) de origem não fisiológica, porém comportamental, em ratos. Estudos posteriores levaram Falk (1969) a descartar definitivamente a hipótese de polidipsia fisiológi-ca, ao mesmo tempo que outros comportamentos foram estudados, como por exemplo: agredir em pombos, lamber jatos de ar em ratos, correr em uma roda de atividade em ratos, roer madeira em ratos, ingerir álcool e outras drogas em ratos e macacos, defecar induzido em ratos, locomover-se em ratos e pombos, e o comportamento comer induzido em ratos (para uma revisão, ver Falk, 1971;Gimenes, 1988;Haydu, 199 1988; Staddon, 1977e Wetherington, 1982. Para uma revisão sobre ingestão de droga e comportamento adjunto, ver Sanger, 1986 e sobre polidipsia e alcoolismo, ver Tang & Falk, 1988).…”

“…A função bitônica que caracteriza a polidipsia foi observada com ataque em sujeitos pombos (Flory, 1969); fuga do esquema em pombos (Brown & Flory, 1972); com o com-portamento de morder em sujeitos macacos submetidos a esquema de FI de liberação de alimento ou choque (Deweese, 1977) e com o comportamento de roer em ratos submetidos a esquema FI de liberação de comida (Roper, 1980). Foi obtida de modo semelhante em crianças para os comportamentos de beber, de "movimentos motores finos" e de "limpeza" {grooming) (Granger, Porter & Christoph, 1984 (Falk, 1969). A mesma relação foi obtida para o comportamento de lamber jatos de ar (Chillag & Mendelson, 1971) e agredir induzido pelo esquema (citado por Wetherington, 1982).…”