Can Meaning Associated with Perceptual Grouping Modulate Attention?

Abstract

In an environment rich with information, performance on a task depends on the ability to select only the relevant pieces of information for achieving a current goal. Cognitive psychologists propose that selective attention helps to segregate the relevant information from the irrelevant information. A combination of bottom-up and top-down factors jointly influences the settings of the attentional filter (Spalek, Falcon & Di Lollo, 2006) such that only task-relevant information is selected for further processing. However, biologically- and socially-important stimuli like affective faces are proposed to influence allocation of attention (Vuilleumier & Schwartz, 2001). Task-irrelevant emotional faces are proposed to capture attention in a way that is detrimental to performance on a primary task (Eastwood, Smilek & Merikle, 2003). The present study was carried out to examine whether task-irrelevant affective faces can capture attention even when attention is maintained in a focused mode. Subjects searched for a unique red target letter (T2) in a stream of black distractor letters presented at the rate of 1item per 84 ms in an RSVP sequence. Two straight lines and a curve were also presented in the periphery and in the same frame as a distractor letter (T1). The perceptual groups formed by the specific arrangements of the peripheral elements (face/ non-face), the time interval between T1 and T2 (lag), and the colour (black irrelevant / red relevant) of the peripheral elements were manipulated. The extent to which the peripheral elements captured attention was measured as differences in the accuracy with which T2 was identified in these different conditions. The results from six experiments indicate that T2 identification was impaired by lag and relevance but not by the presence of a face. Contrary to claims made in the literature the results of the present study indicated that distractions from socially-important stimuli like affective Gestalt faces can be averted when the spread of spatial attention is controlled and when these stimuli do not match the top-down settings adopted for the current task. The observations made in the present study also suggest possible differences between the mechanisms involved when a target is searched in space than when a target is searched in time. Keywords: face, perceptual groupings, attentional capture.