Abstract
Visual salience and perceptual load may both influence the efficiency of visual selection. Previous evidence reported by Gibson and Bryant (2008) suggested that high perceptual load can dominate color salience in a distractor interference paradigm where observers attempted to ignore a salient color singleton under different levels of perceptual load. More recently, Biggs and Gibson (in press) extended this research by investigating whether full vs. no knowledge of the color singleton and/or full vs. no knowledge of perceptual load would modulate the relative operation of these two mechanisms. Consistent with previous findings, Biggs and Gibson found that high perceptual load dominated color salience. However, this result only occurred when advance knowledge of load was not available, and high-load displays were preceded by other high-load displays. More importantly, Biggs and Gibson also found that color salience dominated high perceptual load in other contexts where participants were provided full knowledge of color conditions and display load. This latter finding was unexpected because distractor interference increased as the amount of knowledge provided to the observer increased. The present experiments were designed to further investigate how different forms of knowledge may influence this paradigm; namely, full vs. no knowledge of distractor presence. In the full knowledge condition, the presence or absence of the distractor was fixed within blocks; whereas, in the no knowledge condition, the presence or absence of the distractor was mixed. The results of three experiments suggested that color salience dominated high perceptual load when the observer was able to incorporate this knowledge into a search strategy. Altogether, these findings suggest that the competition between color salience and perceptual load can vary based upon the knowledge provided to the observer and how they choose to integrate that knowledge into search. Implications for theories of top-down control will be discussed.