A reassessment of the pseudoneglect effect: Attention allocation systems are selectively engaged by semantic and spatial processing.

Oliver J Gray,Martyn Mcfarquhar,Daniela Montaldi

doi:10.1037/xhp0000882

Oliver J Gray, Martyn Mcfarquhar + Show 1 more

Open Access

https://doi.org/10.1037/xhp0000882

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Abstract

Healthy individuals display systematic inaccuracies when allocating attention to perceptual space. Under many conditions, optimized spatial attention processing of the right hemisphere’s frontoparietal attention network directs more attention to the left side of perceptual space than the right. This is the pseudoneglect effect. We present evidence reshaping our fundamental understanding of this neural mechanism. We describe a previously unrecognized, but reliable, attention bias to the right side of perceptual space that is associated with semantic object processing. Using an object bisection task, we revealed a significant rightward bias distinct from the leftward bias elicited by the traditional line bisection task. In Experiment 2, object-like shapes that were not easily recognizable exhibited an attention bias between that of horizontal lines and objects. Our results support our proposal that the rightward attention bias is a product of semantic processing and its lateralization in the left hemisphere. In Experiment 3, our novel object-based adaptation of the landmark task further supported this proposition and revealed temporal dynamics of the effect. This research provides novel and crucial insight into the systems supporting intricate and complex attention allocation and provides impetus for a shift toward studying attention in ways that increasingly reflect our complex environments.

Highlights

Public Significance Statement This study describes a previously unrecognized but reliable spatial attention bias that is associated with the processing of the semantic meaning of objects
As it is well established that the bisection of simple lines readily generates leftward bisection errors (Jewell & McCourt, 2000), this experiment aimed to assess the effect of increased target complexity on bisection errors in healthy individuals and improve our understanding of how the effect could generalize across more realistic everyday stimuli
Experiment 1 and 2 led us to expect that the interaction between semantic processing of objects and the left hemisphere’s frontoparietal attention (FPA) network would drive attention allocation preferentially to the right side of visual space

Summary

Introduction

Public Significance Statement This study describes a previously unrecognized but reliable spatial attention bias that is associated with the processing of the semantic meaning of objects. The pseudoneglect effect describes the tendency of healthy individuals to allocate more attention to the left side of perceptual space than the right (Bowers & Heilman, 1980). A traditional mechanistic account (Heilman & Van Den Abell, 1980) states that more efficient visuospatial processing of the left visual field by the right hemisphere’s FPA network increases the perceived size of the left side of the target This size overestimation of the target of attention and/or a size underestimation of the nonattended section of the line results in a shift in the perceived center away from the midline to the left side (for a review of the pseudoneglect effect with the line bisection task, see Jewell & McCourt, 2000)

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