Temporal processes of information transmission from visual search to behavior

This article examines the temporal processes of information transmission by response times (RTs) in visual search. Information (hazard) rate functions of RTs were evaluated for a large dataset provided by Wolfe and colleagues. Set size accounted for a minor portion of the variance of these RTs, and the present analysis examined temporal processes involved in the larger variance within each stimulus and task condition. Momentary information rates were measured by (a) response probabilities sequentially dependent on the proportion of longer RTs, (b) with continuously varying visual influence, and (c) evaluated in bits/s. Results include the following: (1) Rates of information transmission from visual input to behavioral output varied systematically with the RTs in each search condition. (2) Information rate functions for "feature" and "conjunction" tasks were highly nonlinear, with distinct phases of accelerating and decelerating visual influence. Roughly constant information rates occurred in only a few conditions in the "spatial configuration" task. (3) Faster and slower observers responded to qualitatively different visual organizations of target-absent displays in all three tasks. (4) Perceptual organization and response control were synchronized parallel processes.