Perceptual load in searching for sloping colored lines camouflaged by colored backgrounds: a separate-groups investigation.

Altogether 168 men searched briefly for colored sloping lines embedded in a background of random color. Using a separate-groups experimental design, search for six kinds of target was found to be less effective after practice than search for a single kind of target. Reducing the number of colors of targets from three to one was considerably more beneficial than reducing the number of main directions of slope from two to one. Reducing the number of kinds of target without reducing the number of relevant stimulus values was also found to improve the effectiveness of search, but search was even more effective when the number of relevant stimulus colors was reduced. The results can be predicted from the total number of selection operations required. However, a more precise fit needs to reflect the considerably greater difficulty of searching for a number of directions of slope. When targets were poorly camouflaged, search was equally effective whether there were four colors or only a single color of target to search for.