FURTHER EVIDENCE OF A SENSORY-TONIC INTERACTION IN PIGEONS1
This research was supported by Research Grants NSF-GE-5159 and NIH-RO-1–00903-06 under the direction of the first author. These findings were presented by D.R.T. at the October, 1966, meetings of the Psychonomic Society in St. Louis.
Abstract
The five pigeons in Group 1 were given successive intradimensional discrimination training in which responses to a line of 49° were reinforced on a variable-interval schedule and responses to a line of 33° were not reinforced. Subsequent generalization testing with other line orientations revealed a peak shift from the positive stimulus in the direction away from the negative stimulus in all subjects. The four pigeons in Group 2 received successive discrimination training with the 49° value on the key during both stimuli. During the negative stimulus, however, the floor was tilted 16° counterclockwise. When tested (with the floor flat) these subjects showed peak shifts similar to those observed with Group 1. A third group of three pigeons, given successive interdimensional discrimination training with the 49° line as the positive stimulus and the absence of the line as the negative, showed no peak shift in a subsequent generalization test. It was concluded that tilting the floor on which the pigeon stood systematically distorted the bird's visual perception of the orientation of the line in a manner consistent with the results of other studies in this laboratory.
