Where have we gone wrong? Perceptual load does not affect selective attention

Abstract

The theory of perceptual load (Lavie & Tsal, 1994) proposes that with low load in relevant processing left over resources spill over to process irrelevant distractors. Interference could only be prevented under High-Load Conditions where relevant processing exhausts attentional resources. The theory is based primarily on the finding that distractor interference obtained in low load displays, when the target appears alone, is eliminated in high load displays when it is embedded among neutral letters. However, a possible alternative interpretation of this effect is that the distractor is similarly processed in both displays, yet its interference in the large displays is diluted by the presence of the neutral letters. We separated the possible effects of load and dilution by adding dilution displays that were high in dilution and low in perceptual load. In the first experiment these displays contained as many letters as the high load displays, but their neutral letters were clearly distinguished from the target, thereby allowing for a low load processing mode. In the second experiment we presented identical multicolor displays in the Dilution and High-Load Conditions. However, in the former the target color was known in advance (thereby preserving a low load processing mode) whereas in the latter it was not. In both experiments distractor interference was completely eliminated under the Dilution Condition. Thus, it is dilution not perceptual load affecting distractor processing.

Twenty years of load theory—Where are we now, and where should we go next?

“…Remote communities like the Himba, however, have a default attentional state that fully engages cognitive resources with the task at hand. Benoni and Tsal (2010). Distractor interference was assessed under conditions of (A) low load, low dilution; (B) high load, high dilution; and (C) low load, high dilution.…”

Controlling for dilution while manipulating load: Perceptual and sensory limitations are just two aspects of task difficulty

“…It has therefore been argued recently (Benoni & Tsal, 2010;Tsal & Benoni, 2010a, 2010bWilson, Muroi, & MacLeod, 2011) that the reduction of distractor interference under high-load conditions need not be attributed to increases in perceptual load that result from the need to search for the target among the neutral letters. Instead, the reduction could be due to the dilution of the distractor by the neutral letters, as the representations of their features are highly activated in the process of searching for the target.…”

“…Instead, the reduction could be due to the dilution of the distractor by the neutral letters, as the representations of their features are highly activated in the process of searching for the target. Indeed, three different studies (Benoni & Tsal, 2010;Tsal & Benoni, 2010a;Wilson et al, 2011) distinguished between the possible effects of perceptual load and dilution by introducing low-load, high-dilution displays. These displays contained neutral letters (as in high-load conditions) capable of diluting the distractor.…”

Nonconcurrently presented auditory tones reduce distraction

“…Recently, a different line of research has been established assuming that the mere presence of additional stimuli is sufficient, and thus attention does not need to be allotted, for distractor interference to be reduced (Benoni & Tsal, 2010;Tsal & Benoni, in press). This explanation of the perceptual-load effect is based on the so-called Stroop dilution effect (Kahneman & Chajczyk, 1983) and is built upon the early visual interference account proposed by Brown, Roos-Gilbert, and Carr (1995).…”

“…The Stroop dilution effect shows that interference effects in Stroop tasks are diminished when an additional neutral word is presented elsewhere in the visual field. Benoni and Tsal (2010) and Tsal and Benoni (in press) reported evidence that the dilution produced by neutral stimuli is critical, rather than perceptual load, in reducing distractor interference. They introduced a dilution condition similar to a high-perceptualload condition, except that the task-irrelevant stimuli were clearly distinguished from the target (e.g., presented in a different font color).…”