The effect of changes in availability on food selection at different levels of deprivation

In the present study, two experiments investigated the effect of a change in food availability on selection between two food items at different deprivation levels. In the first study, 6 pigeons chose between a nonpreferred food item (i.e., checkers) after a fixed delay and a preferred food item (i.e., corn) after an adjusting delay. The delay to the preferred food item adjusted depending upon the pigeon's choices. The dependent measure was the amount of delay added to corn to produce indifference at 70% and 95% of body weight. Results showed that less delay had to be added when pigeons were more deprived. In the second study, the availability of both corn and checkers was varied by manipulating the amount of each food item presented to the pigeons at 70% and 95% of body weight. The dependent measure was the amount of each item taken. For the nonpreferred food item, consumption depended on an interaction between deprivation and availability. A decrease in availability only affected checker consumption when body weight was at 70%. Together these two studies showed that the effect of a change in food availability on selectivity was greater when pigeons were more deprived.