Dilution: A theoretical burden or just load? A reply to Tsal and Benoni (2010).

Abstract

Load theory of attention proposes that distractor processing is reduced in tasks with high perceptual load that exhaust attentional capacity within task-relevant processing. In contrast, tasks of low perceptual load leave spare capacity that spills over, resulting in the perception of task-irrelevant, potentially distracting stimuli. Tsal and Benoni (2010) find that distractor response competition effects can be reduced under conditions with a high search set size but low perceptual load (due to a singleton color target). They claim that the usual effect of search set size on distractor processing is not due to attentional load but instead attribute this to lower level visual interference. Here, we propose an account for their findings within load theory. We argue that in tasks of low perceptual load but high set size, an irrelevant distractor competes with the search nontargets for remaining capacity. Thus, distractor processing is reduced under conditions in which the search nontargets receive the spillover of capacity instead of the irrelevant distractor. We report a new experiment testing this prediction. Our new results demonstrate that, when peripheral distractor processing is reduced, it is the search nontargets nearest to the target that are perceived instead. Our findings provide new evidence for the spare capacity spillover hypothesis made by load theory and rule out accounts in terms of lower level visual interference (or mere “dilution”) for cases of reduced distractor processing under low load in displays of high set size. We also discuss additional evidence that discounts the viability of Tsal and Benoni's dilution account as an alternative to perceptual load.

Perceptual load effects on processing distractor faces indicate face-specific capacity limits

“…crosstalk among visual features , 2012Wilson, Muroi, & MacLeod, 2011) instead of a draw on perceptual capacity as we propose here (as well as in the original concept of dilution, Kahneman & Chajczyck, 1983, and its later application to distractor faces, Jenkins, Lavie & Driver, 2003). Although there are now demonstrations that dilution effects are indeed explained by a draw on perceptual capacity as proposed in load theory (e.g., capacity spills over to the closer items to the target, or those grouped with it, in cases where it is not allocated to the distractor, see Lavie & Torralbo, 2010;Yeh & Lin, 2013), it seemed worthwhile to address it here (see Note 2). Thus in Experiment 4, in addition to the low and high load conditions, we also included a new 'low-load/dilution' condition, in which the displays contained one intact face target presented among scrambled nontarget faces.…”

“…Indeed, in the case of dilution conditions in which the relevant set size is varied (rather than a distractor added in one of the irrelevant distractor positions) a failure to find a dilution effect is already documented. Lavie (1994) did not find effects of dilution, despite the use of a very similar task and design used later on in some of Tsal and Benoni's (2010) experiments (see Lavie & Torralbo, 2010, for a more detailed discussion of this point).…”

The Effect of Visual Perceptual Load on Auditory Awareness in Autism Spectrum Disorder

“…neutral letters) competed with those of the distractor, thus degrading the quality of its visual representation and leading to reduced distractor processing. Lavie however has attempted to counter this claim by demonstrating that in low perceptual load/high search set size displays, capacity in fact spills over into processing the non-target items in the search array, therefore ruling out an alternative explanation in terms of dilution (Lavie and Torralbo 2010). Lavie and Torralbo (2010) also point out that their interpretation of perceptual load effects in terms of dilution only pertain to one specific manipulation of perceptual load.…”

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

“…However, Tsal and Benoni's (2010) conclusions were criticized in a response by Lavie and Torralbo (2010). who maintained that the dilution argument is built on a misunderstanding of the load hypothesis-namely, the involuntary nature of attention spillover.…”