Attack behavior as a function of minimum inter-food interval

Pigeons were exposed to a procedure in which food was presented after a fixed period of time had elapsed, provided no attack against a nearby stuffed pigeon had occurred during the last 15 sec of the period. As the minimum inter-food interval was increased logarithmically through seven values from 15 sec to 960 sec, attack increased to a maximum and then decreased. For both pigeons, attack predominantly occurred after, rather than shortly before, food deliveries.     

Schedule-induced polydipsia as a function of fixed interval length

Rats were trained to bar-press for Noyes pellets on an FI schedule which was increased serially through several values from 2 sec to as high as 300 sec. Concurrently, water was freely available. As FI length was increased, the degree of polydipsia increased linearly to a maximum value.     

Children's reactions to failure as a function of interresponse interval

Several studies have reported that nonreward facilitates subsequent performance; other studies have found that failure is followed by a performance decrement. Experiments that have shown facilitating effects of nonreward have used interresponse intervals of at least 5 sec, whereas those that have shown decremental effects of failure have used 0-sec interresponse intervals. The present study examined the effects of .5-, 1.0- and 5.0-sec interresponse intervals on children's lever-pulling responses following success and failure on a ball tower task. Second- and third-grade children responded slower following failure relative to success with .5- and 1.0-sec interresponse intervals. Speeds following success and failure did not differ when the interresponse interval was 5.0 sec. Increases in interresponse interval were associated with increases in speeds following failure, but speeds following success were not related to interresponse interval. These results were discussed in terms of frustration-produced competing responses and Elliott (1970) analysis of the influence of preparatory intervals on children's reaction-time performance.     

Changing food preference as a function of mood

The authors investigated the effect of mood on food selection. Participants (N = 98) indicated the likelihood of general eating and the likelihood of eating specific foods after reading and projecting themselves onto the events and emotions described in a sad and a happy vignette. Both men and women believed they were more likely to consume food following a happy versus a sad event, and men believed they were significantly more likely to eat than did women. However, the type of food men and women believed they would consume interacted with the type of event experienced. Vegetarian snack foods were more likely to be consumed following a happy versus a sad event, with men more likely to eat snack foods. Men did not significantly change in likelihood of consuming sweet foods as their mood changed. However, women believed they were more likely to consume sweet foods following a sad event. The authors discuss the results in terms of a self-medication hypothesis and the effect of carbohydrates on central serotonin and endogenous opioids. Overall, results demonstrated that mood influences belief in the likelihood of food selection.     

Autoshaping as a function of prior food presentations

Young chickens were given 1, 10, 100, or 1000 presentations of grain in a hopper. Subsequently, the key was illuminated before each presentation of grain to study autoshaping of the key-peck response. The number of keylight-grain pairings before a bird first pecked the lighted key was found to be a U-shaped function of the number of prior food-only presentations, with pecks occurring significantly sooner after 100 food-only trials than after any of the other values. Two of five chicks at the 100-trial value pecked on the first illumination of the key. Experiment II showed further that when a series of food-only trials (no keylight) preceded keylight-only trials (no food) 30% of the chicks pecked the illuminated key. Experiment III extended the generality of first-trial pecking to pigeons. After preliminary training with food-only, two of five pigeons pecked on the first illumination of a key. The results suggest a close relationship between autoshaping and pseudo-conditioning.