Automatic Processing and the Unitization of Two Features.

In a series of experiments conjunction target detection search color and shape was compared with single feature search color or shape. With appropriate training and sufficient practice, subjects could unitize the features in conjunction condition. Unitization was defined as occurring when performance of the conjunction condition was similar to performance on a single feature condition. In four visual search experiments, performance on conjunctions and single feature shape searches was highly similar across three criteria 1 slope, 2 positive to negative slope ratios, and 3 percent variance accounted for by the linear component. In another experiment, unitization was shown to be dependent on the type of mapping, either consistent or varied, in a multiple-frame detection experiment. Two other experiments further examined characteristics of single and conjunction feature conditions. In one, the stability of the integral-separable dimension distinction was examined across time. Problems with this approach and distinctions between integrality and unitization were discussed. Another experiment compared single feature and conjunction conditions in a texture segregation task. With training, conjunction performance was about equal to or better than initial single feature conditions. The relationships between unitization and automatic processing were discussed. Author