Age-related changes in the allocation of spatially directed focal attention

Abstract

ABSTRACT Objectives Leftward deviation on a horizontal line bisection test (pseudoneglect) might be induced by right hemispheric dominance for mediating spatial or global attention, or a hemispheric asymmetry in the ability to spatially disengage attention. With aging, this leftward bias is reduced, likely due to the aging-related deterioration of right hemisphere mediated functions (right hemi-aging) or hemispheric asymmetry reduction in old adults (HAROLD). Methods Forty-seven healthy adults divided into younger and older groups performed a modified Posner spatial-attentional task. Results Overall, younger individuals responded faster to left than right-sided imperative stimuli. In contrast, older participants did not reveal a right-left asymmetry to imperative stimuli. The younger group also revealed a strong inverse relationship between the reaction time to right valid cues and the leftward attentional bias while performing the line bisection task (pseudoneglect). Conclusions Our results provide support for both the right hemisphere spatial-attentional dominance hypothesis of pseudoneglect and the right hemi-aging hypotheses.