Interocular transfer of learning in the pigeon: Visuo-motor integration and separation of discriminanda and manipulanda

Lateralized Interhemispheric Transfer of Color Cues: Evidence for Dynamic Coding Principles of Visual Lateralization in Pigeons

“…As findings from the present and other studies show, there appears to be a gradient in the occurrence of interhemispheric transfer from zero to almost perfect. As in this study, simultaneous color or pattern discriminations have produced successful interocular transfer in other experiments with pigeons (Watanabe, 1986;Diekamp et al, 1999), whereas in a spatial conditional discrimination task no successful transfer was observed (Green et al, 1978). Such discrepancies have brought about a vivid discussion about the essential prerequisites for the transmission of a learned visual information.…”

“…In principle this resembles the results of the present study in which the initial transfer occurs from the left hemisphere, which is dominant for visual object features, to the right. Since in pigeons, IOT of intensity and color information has been shown to occur (Francesconi et al, 1982;Watanabe et al, 1986) and since the left hemisphere is involved in color-as well as in brightnessdiscrimination tasks, we assume that the data would apply equally if the pigeons in this study would have used brightness instead of color of the stimuli. As findings from the present and other studies show, there appears to be a gradient in the occurrence of interhemispheric transfer from zero to almost perfect.…”

“…Such discrepancies have brought about a vivid discussion about the essential prerequisites for the transmission of a learned visual information. Watanabe (1986) suggested the spatial separation of the discriminative stimulus and the pecking key to be decisive for IOT absence and suggested successful transfer to be inhibited if a visual signal has to be integrated with a motor response. Goodale and Graves (1981), on the other side, suggested that differences in retinal locus with which lateral versus binocular fixation is achieved is crucial for transmission.…”

Limits of intraocular and interocular transfer in pigeons

“…Learning to discriminate between two shapes in the lateral visual field while walking between two feeders in an open arena has been demonstrated to be a very demanding task for the pigeons. Long distances between the discriminative stimuli and the response site may increase the difficulties of a discrimination task [45].…”

“…However, in an experiment in which the stimuli were displayed on a vertical screen above ground level, interocular transfer was not observed [1]. Two hypotheses were proposed to explain these contradictory results: the "sensorimotor integration" hypothesis [46,45] and the "retinal locus" hypothesis [23][24][25]10,26].…”