Selective information processing

Past studies have shown that in certain tasks, subjects are not able to selectively attend to specific areas of a visual display even if instructed to do so. Yet, a more recent study (Graves, 1976) has used the concept of selective attention to explain the difference between the number of items processed in forced choice detection tasks and the number processed in full report tasks. Graves proposed that only identification processing is necessary in the detection task, while both identification and position processing are required in the full report task. A problem with Graves' task is that it requires memory searching after stimulus presentation, probably reducing the predicted number of items processed. The experiment reported here utilized partially filled arrays and required responses based upon only positional processing, or only identification processing, or both types of processing. In direct contradiction to Graves' conclusions, the results showed that although subjects could inhibit identification processing while engaged in positional processing, the reverse was not true. In addition, positional processing was shown to be faster than identification processing.