Results of the Experiment

For our analyses, we concentrated on the target localization accuracy of the pigeons' first peck to a display. This response measure was used because it best isolates the effects of display change on the birds= search and target localization behavior. The three panels below show mean first target localization accuracy for the target-variable, distractor-variable and display-variable conditions, respectively as a function of temporal rate of change within the display. The lower reference line in each figure is the chance target localization value. The upper reference line in each figure shows mean performance with the static color baseline displays. Overall, the pigeons performed above chance in all conditions, indicating that they successfully extracted at least some target location information from all of the dynamic RSVP conditions. Overall, the target-variable conditions supported the best performance, in some cases being even better than with the highly familiar static displays. Performance in the display and distractor-variable conditions was somewhat poorer, and generally more sensitive to changes in the rate at which changes occurred in the display.

These results, to our knowledge, are the first documented evidence of the ability of pigeons to process such rapidly presented quasi-sequential visual information in a target search task. Despite the dynamically changing color values in the various RSVP conditions, the pigeons retained the capacity to locate the target region in these textured stimuli even at the fastest rates. Of most theoretical importance was performance in the 100 ms display-variable condition, where an entirely new display appeared every tenth of a second yet accuracy showed only a moderate drop in comparison to the static displays. A second important new finding was the superior localization accuracy observed whenever a display's dynamic changes were associated exclusively with the target -- and in some cases actually resulting in elevated performance above that recorded with the highly familiar static displays. These results have important implications for our understanding of how pigeons perceive, search, select, and process complex, hierarchically-arranged, visual information. These further clarified in the actual printed article. To this article's home page

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Dynamic Texture Stimuli Same-Different & SDT Same-Different w/ Multiple Stimuli

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12/20/00