Multiple-element line segment precues: orientation and location effects on attention.

Three experiments were conducted to examine the hypothesis that a uniquely oriented line segment located at the end of the directional flow produced by the alignment of the long axes of identically oriented background segments will not be detected as rapidly as when the segment appears at locations within the flow. The hypothesis was supported with response time measured in Experiment 1. A location-cuing task was used in the last two experiments, with the unique segment becoming a precue to indicate the location of an upcoming target character, accuracy was the dependent measure. Poorer detection of the unique segment at end-of-flow locations was shown not to be due to a local configuration effect produced by the uniquely oriented segment in conjunction with the segment on either side. The time course of attentional development with multiple-segment precue displays was comparable to that with an arrow at fixation as the precue, and slower than that with a line segment appearing alone.