Association for Behavior Analysis International

Motivating Operations (MOs) are frequently manipulated (by altering access to commodities and manipulating other variables such as body weight) in order to change responding. This study had two aims, firstly to investigate the effect of altering body weight on concurrent schedule performance of hens, secondly to investigate the effect of altering body weight on the time duration of each component of hens' pecks under these schedules when analysed from high speed videos filmed at 240 fps. Six hens (at 85% 5%) were shaped (three via the method of successive approximations and three via autoshaping) to respond for food reinforcers on an infra-red screen. Hens then responded under a range of concurrent VI VI schedules, with body weight held at 85% 5%, 95 5% and 100 5% over conditions. It was found that applying the Generalised Matching Law to the data did not result in any consistent differences in responding with the three body weights. However, response rates, inter-response times and video analysis of the individual components of the hens pecking responses did show consistent differences between responding at the three weights.

Because human behavior typically consists of more than two choices it is essential to expand choice procedures and models to three or more alternatives. Unfortunately, the typical procedures necessarily produce a bias. The present experiment used a novel choice procedure, essentially a Findley procedure with two switching keys to prevent apparatus induced biases. The stay/switch model is a novel approach to understanding choice. In standard two choice procedures, it is unclear whether subjects are switching from an alternative or switch to an alternative, as these choices are confounded. Three alternatives unconfounds these choices. Some conditions were standard concurrent arrangements with symmetrical arrangements of stay and switch schedules. Other conditions used non-symmetrical arrangements. Four pigeons were exposed to seven to nine conditions of three alternative choice until responding was stable for five sessions. Despite the complex contingencies, preference changed in accord with changes in reinforcement schedules in symmetrical conditions. Additional analyses will compare stay/switch models based on switching to an alternative to models based on switching from an alternative. Models will be compared using Jensen's (2014) compositional analysis.