Wavelength Generalization by the Method of Successive Paired Comprison in Pigeons

Abstract

In the present experiment an attempt was made to study wavelength generalization, employing the key-pecking response in the pigeon. Sixty experimentally naive pigeons (fifteen groups) were trained on a single monochromatic light stimulus (480 nm). One hundred continuous reinforcements for two days and seventy five one minute variable interval reinforcements for the following five days were given to each S. On the eighth and ninth day, the generalization test was carried out under extinction. Each S was successively presented one pair of stimulus ranging from 480 nm to 630 nm by the step of 30 nm. The following results were obtained :
1) Generalization gradients were also obtained through this successive-paired-comparison like method.
2) Number of responses for a pair of stimuli at the extinction of each group was increasing at the CS and stimuli near CS
3) No difference was found between groups in the number of total responses in the test period.
4) Generalization gradients were not a mere function of physical distance.
5) Comparison of the slope of generalization gradients obtained from the groups whose two test stimuli were separated by the range of 510mm-540mm with that obtained from the groups whose two test stimuli were not revealed that the former is steeper than the latter. This might be taken to suggest the existence of the categorization in the pigeon.
This study shows that the method of paired comparison was a very efficient one in the study of wavelength generalization in pigeons.