The effect of a horizontally structured field and target brightness on visual search and detection times.

Abstract An experiment was performed in which detection, times were compared for free and systematic search for a small visual target. Three different levels of target brightness were employed. The systematic search pattern consisted of a horizontal zig-zag between pairs of lines drawn on the visual field. The major findings were (1) that the systematic search and structured visual field only reduced the detection times of low contrast targets, and (2) that target contrast was an important variable independent of the condition of the visual field and the search instructions used. Subsequent analysis of the data revealed that the systematic search results could not be explained in terms of an increased uniformity of coverage of the visual field.