Limitations of rapid parallel processing in the detection of long and short oriented line targets

The purpose of this study was to determine whether the detectability of a uniquely oriented line element in a field of uniformly oriented line elements depends on element length. Displays containing various numbers of elements were presented briefly and followed by a mask. The length and orientation of the elements were varied. With longer (1.0-deg) elements, detection performance varied little with the number of elements present. With shorter (0.25-deg) elements, performance worsened as the element number increased, especially when the uniformly oriented elements were oblique. It seems that rapid spatially parallel processes facilitate detection of targets in many-element displays of long elements but not of short elements.