In this essay, we evaluate the applied implications of two articles related to the matching law and published in the Journal of the Experimental Analysis of Behavior , May 1994. Building on Mace's (1994) criteria for increasing the applied relevance of basic research, we evaluate the applied implications of basic research studies. Research by Elsmore and McBride (1994) and Savastano and Fantino (1994) involve an extension of the behavioral model of choice. Elsmore and McBride used rats as subjects, but arranged a multioperant environment that resembles some of the complex contingencies of human behavior. Savastino and Fantino used human subjects and extended the matching law to ratio and interval contingencies. These experiments contribute to a growing body of knowledge on the matching law and its relevance for human behavior.

Manipulation of the food supply can induce either intense hyperactive wheel running or a fatal activity anorexia in rats that is strongly analogous to that seen in humans. The abnormal behaviour is accompanied by alterations in the diurnal pattern of activity. As part of a detailed study of hyperactivity and anorexia, spontaneous wheel running by male rats was studied under three conditions: ad libitum feeding; restriction to 15 g of food per day; and restriction to a single 90-min meal per day. Ad libitum fed rats increased their running at the rate of 440 ± 60 m/day per day, stabilizing after day 10 at 6045 ± 3010 m/day. The running occurred in short bursts throughout the dark period and at the beginning of the light period. Rats restricted to 15 g/day increased their running at the significantly greater (p < 0.001) rate of 1230 ± 120 m/day per day, reaching 12 200 ± 4090 m/day by day 10 and thereafter stabilizing at 13 600 ± 4 160 m/day. The running was initially triphasic and confined to the dark period but eventually progressed to a biphasic pattern. The rats restricted to a single 90-min access period to food each day showed an even greater rate of increase in running, attaining 1930 ± 288 m/day per day (p < 0.02 vs. 15 g/day group). These animals decreased eating and decompensated by day 4. The diurnal pattern of activity was disturbed from day 1 of the protocol, and by day 4 the rats ran essentially continuously throughout the daily cycle. The sensitivity to hyperactivity is a function of the severity of food restriction in this animal model of hyperactivity. It is paralleled by a marked disturbance of the diurnal pattern of activity, suggesting that the hyperactivity is related to a basic central nervous system dysfunction.Key words: hyperactivity, diurnal variation, rat.

The relationship between basic research with nonhumans and applied behavior analysis is illustrated by our work on activity anorexia. When rats are fed one meal a day and allowed to run on an activity wheel, they run excessively, stop eating, and die of starvation. Convergent evidence, from several different research areas, indicates that the behavior of these animals and humans who self-starve is functionally similar. A biobehavioral theory of activity anorexia is presented that details the cultural contingencies, behavioral processes, and physiology of anorexia. Diagnostic criteria and a three-stage treatment program for activity-based anorexia are outlined. The animal model permits basic research on anorexia that for practical and ethical reasons cannot be conducted with humans. Thus, basic research can have applied importance.

Cross-sectional studies have suggested that total and bioavailable testosterone levels are reduced in some male athletes. Such changes may be related to loss of body weight, increased serum cortisol, and/or alterations in LH pulsatile release. To determine how endurance training may affect androgen levels, we measured serum total testosterone, sex hormone-binding globulin, free androgen index, LH, FSH, PRL, cortisol, and weight in 15 previously sedentary males. We also examined pulsatile LH release in a subset of 5 subjects. Over 6 months of training, the men increased weekly running mileage to an average of 56 km/week. Total testosterone and free androgen index levels decreased significantly. PRL and cortisol also decreased, while single sample LH and FSH remained unchanged. There was a significant reduction in weight, which did not correlate with changes in serum testosterone levels. LH pulsatile release was not altered by training in the subset of 5 runners. These data confirm previous findings of physiological reduction in serum testosterone and PRL levels and suggest that the testosterone decrease is not related to changes in LH pulsatile release, weight, or increased serum cortisol levels.

When rats are fed one meal a day, they lose weight but soon adjust their food intake and survive. Interestingly, when these animals are exposed to the same food schedule and allowed to run on a wheel, they die of starvation (Epling et al. 1981, 1983). Wheel running becomes excessive if food is restricted and animals may complete more than 10000 turns per day, a distance equivalent to 10 km. This excessive activity interferes with feeding and causes a steady decline in body weight. As wheel running peaks, animals may stop eating — even though this is not required by the experimental procedures. We have called this process activity-based anorexia and we have argued that a similar anorexia occurs in humans (Epling and Pierce 1988).

The JCR:LA-corpulent rat is a congenic strain that, if homozygous for the cp gene, is obese with a very low-density lipoprotein hyperlipidemia and is insulin resistant. The male corpulent rats develop atherosclerotic lesions of the major arteries and myocardial lesions. Corpulent and lean male rats were induced through mild food restriction to run intensively (approximately 6,000 m/day) from 6 wk to 6 mo of age. Food restriction, especially when coupled with running, lowered all classes of lipids in the whole serum of corpulent rats. The principal changes in lipid concentrations were in the very low-density lipoprotein fraction. Food restriction caused a significant drop in fasting insulin levels of corpulent rats and decreased beta-cell hyperplasia. Both effects were more marked in the running animals. There was a significant decrease in myocardial lesion frequency in the food-restricted corpulent rats and an absence of lesions in the running rats. The results indicate that intensive physical activity can largely correct the lipid abnormalities and insulin resistance of this atherosclerosis-prone strain, and these changes are associated with inhibition of the disease process. However, moderate food restriction has similar effects, and the greater effects seen with intensive running may simply reflect an effectively more severe metabolic restriction in the presence of the exercise.

A biobehavioral model of activity-based anorexia is examined in terms of recent evidence. Strenuous exercise reduces the value of food reinforcement and results in decreased food intake. Reduction of food intake increases the motivational value of physical exercise. This produces an escalation in activity that further suppresses appetite. Cultural practices of diet and exercise initiate this anorexic cycle, and once started the process is resistant to change. These anorexias may be the result of natural selection favoring those organisms that became active in times of food scarcity. Proximate physiological mechanism(s) appear to involve the endogenous opiate system that mediates the relationshp between running and eating. It is argued that classification of human self-starvation should be based on environmental and/or biological conditions that control food regulation. Activity anorexia may be one instance of such a classification that could account for many instances of "an orexia nervosa".

The rat is widely used in studies of the metabolic and physiological effects of physical exercise. The most commonly used form of exercise is running on treadmills or mechanically driven running wheels. Rats will not voluntarily run significant distances, under normal circumstances. If rats are exposed to running wheels with food freely available, only very limited activity normally occurs. When rats with access to a running wheel are restricted to a fixed amount of food, presented once per day, consistent running occurs. The running is spontaneous and very sensitive to the amount of food provided. Six 6-wk-old rats of 197 g mean body wt were induced to run for 139 days. The distance run increased rapidly over a 20-day initial period on a food supply of 15 g/day (vs. 19.5 g/day consumption by sedentary controls). From day 20 to day 139 the mean distance run was described by the regression equation distance (m/day) = 10,410 - 37.9 X days. Food provided was varied according to distance run, ranging from 15 to 18 g/day, and was normally 17.5 g/day. Thus a food deprivation of 10% of normal consumption will result in mean distances run of approximately 8,000 m/day. The use of pair-fed control animals without access to a wheel allows the conduct of experiments to test the effects of chronic long-distance running. The running is spontaneous; thus the technique avoids the complications accompanying techniques that force running.

Two experiments were designed to assess whether depriving rats of food would increase the reinforcement effectiveness of wheel running (Experiment 1) and whether satiation for wheel running would decrease the reinforcement effectiveness of food (Experiment 2). In Experiment 1, a progressive-ratio schedule was used to measure the reinforcement effectiveness of wheel running when rats were deprived or not deprived of food. Completion of a fixed number of lever presses released a brake on a running wheel for 60 s, and the response requirement was systematically increased until the rat stopped pressing or until 8 hr had elapsed. The ratio value reached (and the total number of lever presses) was an inverted-U function of food deprivation (percentage body weight). In Experiment 2, when wheel running preceded test sessions, fewer food-reinforced lever presses were maintained by the progressive-ratio schedule, and responding occurred at a lower rate on a variable-interval schedule. An interpretation of these results is that deprivation or satiation with respect to one event (such as food) alters the reinforcement effectiveness of a different event (such as access to wheel running).

This note presents a serendipitous result of an operant experiment on choice in human communication. Evidence suggests that demand characteristics associated with the experimenter-subject relationship can control verbal utterances and over-ride programmed operant contingencies.