Modeling the Effects of Perceptual Load: Saliency, Competitive Interactions, and Top-Down Biases.

Kleanthis Neokleous,Marios N Avraamides,Andria Shimi

doi:10.3389/fpsyg.2016.00001

Kleanthis Neokleous, Marios N Avraamides + Show 1 more

Open Access

https://doi.org/10.3389/fpsyg.2016.00001

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Abstract

A computational model of visual selective attention has been implemented to account for experimental findings on the Perceptual Load Theory (PLT) of attention. The model was designed based on existing neurophysiological findings on attentional processes with the objective to offer an explicit and biologically plausible formulation of PLT. Simulation results verified that the proposed model is capable of capturing the basic pattern of results that support the PLT as well as findings that are considered contradictory to the theory. Importantly, the model is able to reproduce the behavioral results from a dilution experiment, providing thus a way to reconcile PLT with the competing Dilution account. Overall, the model presents a novel account for explaining PLT effects on the basis of the low-level competitive interactions among neurons that represent visual input and the top-down signals that modulate neural activity. The implications of the model concerning the debate on the locus of selective attention as well as the origins of distractor interference in visual displays of varying load are discussed.

Highlights

Our successful daily cognitive functioning relies heavily on our ability to select and process only a small subset of the information that is registered by our sensory organs and ignore the rest
It is accepted that the locus of selection is flexible (Chun and Wolfe, 2000; Luck and Hillyard, 2000; Luck and Vecera, 2002) and promising theories, such as the Perceptual Load theory (PLT) have been proposed to reconcile the debate concerning the locus of selection
The model was able to simulate the basic pattern of findings observed in perceptual load studies (e.g., Lavie and Cox, 1997), the findings regarding the interaction of perceptual load with cueing (Johnson et al, 2002; Neokleous et al, 2009), the findings from the comparison of central and peripheral distractors (Beck and Lavie, 2005), and the results supporting a dilution explanation (Benoni and Tsal, 2010)

Summary

Introduction

Our successful daily cognitive functioning relies heavily on our ability to select and process only a small subset of the information that is registered by our sensory organs and ignore the rest. A central topic of debate in the field of selective attention has been the locus of attentional filtering within the stream of information processing. “early selection” theories of attention (e.g., Broadbent, 1958) placed selection of visual stimuli at an early stage of processing claiming that it takes place on the basis of physical characteristics of stimuli such as their color, orientation etc., and prior to extracting their meaning. “late selection” theories (e.g., Deutsch and Deutsch, 1963) posited that selection occurs at a later stage and after all stimuli have been processed semantically. The “attenuation” theory (e.g., Treisman, 1960) proposed that the selection process is the outcome of a filtering mechanism that attenuates rather than completely blocks the unattended stimuli whose threshold of activation is lowered based on significance, conditional probability, or contextual constraint. It is accepted that the locus of selection is flexible (Chun and Wolfe, 2000; Luck and Hillyard, 2000; Luck and Vecera, 2002) and promising theories, such as the Perceptual Load theory (PLT) have been proposed to reconcile the debate concerning the locus of selection (in which we return to shortly)

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