Development of a world-wide web based contour integration test

Possibilities for dynamic psychophysical experimentation on the World-Wide Web are just beginning to be explored. We sought to develop a Web-based version of a contour integration test that is suitable for clinical studies, and to determine whether the previously described contour integration deficit in schizophrenia could be replicated using the new test. Fields of Gabor patches against a gray background were used as stimuli, and a closed contour had to be located within a noisy background. A two-alternative forced-choice paradigm was developed in which the subject had to identify which direction an egg-shaped contour was pointing. The signal-to-noise ratio of the images, and the spacing between contour elements were kept constant, but the orientation of the contour elements was varied as the critical manipulation. The program to administer the task and record data was implemented within Java. Past results of a contour integration deficit in schizophrenia were replicated. Potential future uses of this test for clinical and research purposes are discussed. (c) 2004 Elsevier Ltd. All rights reserved.