Reduction in distraction due to perceptual load: A failure to replicate

Perceptual load theory states that there are limited processing resources, but that these must always be fully employed. It has been used to predict and explain the commonly reported finding that irrelevant distractors influence behaviour when the task has low load (such as processing just one target element) but not when the task has high load (processing many target elements). We attempted to replicate this effect over a series of six experiments that manipulated the location of the distractor, the duration of the display, and different levels of load. We examined both the distracting effects caused by a "neutral" distractor, and response-biases (congruence effects) that occur when the distractor is either congruent or incongruent with the target. Strong distraction and congruence effects were found with central distractors and weaker effects were found with peripheral distractors. These effects appeared to be independent of the level of perceptual load in all conditions. Our findings thus do not support the tenants of perceptual load theory and fail to replicate the many findings that do support this theory.