Optimizing the use of information: The strategic control of the activation of responses

Recent theories of information processing propose that visual information is processed in parallel during an early phase, and serially during a later phase. Depending on stimulus conditions, subjects respond sometimes during the parallel phase, and sometimes during the serial phase. This may suggest that the selection of the phase used to respond is determined by "bottom up", data-driven mechanisms. However, it is possible that under appropriate conditions this selection may be strategic and dependent on "top down", context-driven mechanisms. This hypothesis is investigated here by using the noise-compatibility paradigm, in which flanking noise letters interfere with the identification of a target letter. Previous studies indicated that the interference effect is in part the result of the activation of responses on the basis of evidence accumulated during the parallel processing phase. In this paper, the subjects' expectancy for compatible and incompatible noise was manipulated in four experiments. The results indicate that the noise-compatibility effect is modulated by the subjects' expected utility of target and noise information. This modulation can occur very rapidly and in response to arbitrary stimuli. These findings suggest that subjects' expectancies about the relative utility of the information extracted during the parallel and serial phases determine which phase is used to activate responses, and that the selection between these two phases is strategic in nature.U of I OnlyETDs are only available to UIUC Users without author permissio