Abstract
In a world full of distractions, there is a constant need for human cognitive systems to separate the wheat from the chaff— that is, to selectively attend goal-relevant sensory input and generate appropriate responses, all while ignoring irrelevant information (Carrasco, 2011). Compensating for the limited processing capacity of perceptual and cognitive systems, attention is a selective process, and visuospatial attention specifically has been studied extensively and characterized via prominent models of neural competition (Desimone & Duncan, 1995).
Visual attention has been likened to a spotlight (C. W. Eriksen & Hoffman, 1972; Posner et al., 1980) whose spatial extent narrows over time in order to enhance processing of goal-relevant targets (C. W. Eriksen & St. James, 1986; White et al., 2011). Behavioral and neurophysiological studies have shown that the spatial properties of the attentional “spotlight” are malleable, and may be altered by stimulus properties or task demands (Dubois et al., 2009; C. W. Eriksen & St. James, 1986; M. M. Müller & Hübner, 2002; Pan & Eriksen, 1993). Less effort has been devoted to characterizing the temporal dynamics of spatial selective attention.
Herein I present a set of four theory-driven studies that use complementary protocols and tools in an effort to elucidate the spatiotemporal dynamics of selective attention in a widely used conflict task, the Eriksen flanker task (B. A. Eriksen & Eriksen, 1974). Study 1 investigated the temporal dynamics of spatial selective attention in the flanker task by manipulating target-distractor stimulus onset asynchrony and analyzing congruency effects across response time distributions. In Study 2, I manipulated stimulus location to investigate how spatial uncertainty influences behavioral responses in the flanker task. Study 3 explored the effects of dynamic perceptual inputs on congruency effect magnitude. Study 4 extended Study 2 by investigating neural correlates of conflict processing using electroencephalography. Together, my results across these studies demonstrate that the time course of target selection in Eriksen’s flanker task is modulated by subtle variations in both spatial and temporal features. This work contributes to a deeper understanding of the interplay among visual selection, spatial uncertainty, and neural dynamics, shedding light on underlying mechanisms of visuospatial attention and cognitive control.