The Influence of the Attention Set on Exogenous Orienting

The Influence of the Attention Set on Exogenous Orienting Ahnate Lim (ahnate@hawaii.edu) Department of Psychology, University of Hawaii at Manoa 2530 Dole Street, Honolulu, HI 96822 USA Scott Sinnett (ssinnett@hawaii.edu) Department of Psychology, University of Hawaii at Manoa 2530 Dole Street, Honolulu, HI 96822 USA Abstract The processing of incoming sensory information relies on interacting mechanisms of sustained attention (the ability to focus attention and ignore irrelevant stimuli) and attentional capture (the ability of certain stimuli to reflexively attract one’s attention). Being able to precisely predict what can capture attention when it is engaged in a demanding task is important both for understanding the nature of attention as a cognitive system and also for practical applications. While evidence indicates that exogenous capture, a mechanism previously understood to be automatic, can be eliminated while concurrently performing a demanding task, we reframe this phenomena within the theoretical framework of the ‘attention set’ (Most et al., 2005). Consequently, the specific prediction that cuing effects should reappear when dimensions of the cue overlap with those in the attention set (i.e., elements of the demanding task) was empirically tested and confirmed. Suggestions for further theoretical refinement and empirical testing are discussed. Keywords: Theories of attention; attention set; exogenous cuing; orienting; attentional capture; perceptual load Introduction As an information processing mechanism, one of the characteristic dichotomies of attention is how it must have the capacity to be both focused and distractible at the same time. The ability to ignore irrelevant stimuli and closely attend to a specific task at hand is fundamental to goal directed behavior. Conversely, the ability to be distracted by potentially dangerous events or to be drawn towards relevant information outside the current task or area of focus can be crucial for avoiding harm and responding effectively to the environment. In fact, neurological evidence has demonstrated that these dissociable mechanisms are underpinned by distinct and interactive neural networks (Corbetta, Patel, & Shulman, 2008; Corbetta & Shulman, Many of the attentional mechanisms that we use on a daily basis can be characterized by the way in which they enable goal-directed and top-down control of behavior. Indeed, top-down attentional control has been observed to play a role in visual search (Wolfe, 2007), endogenous (participant directed) orienting of attention to spatial locations (Posner, 1980), and even feature integration (Treisman & Gelade, 1980), to name but a few. Although the environment may contain stimuli that actively compete for and capture attention, what ultimately becomes selected for subsequent processing can be influenced by “top-down signals” that filter for behaviorally relevant objects (Desimone & Duncan, 1995). Considering the importance of responding effectively to changes in the environment, the attentional system allows for stimuli to ‘reflexively’ capture attention, in a ‘bottom- up’ environmentally triggered fashion. It has been shown that this aspect of attention can be dependent on the particular nature of the stimuli and environmental circumstances at hand. Such factors may include the role of stimulus saliency (Jonides & Yantis, 1988) and relevancy to behavioral goals (Yantis & Egeth, 1999), for example. Of direct interest to the current study, recent research has suggested that the reflexive orienting of attention can, at times, be interrupted when an observer is undergoing a difficult and demanding task (Santangelo, Belardinelli, & Spence, 2007). In other words, where such exogenous, or stimulus-driven, mechanisms were previously thought to be automatic (Muller & Rabbitt, 1989), more recent evidence has suggested that these effects may be eliminated in a state of focused attention. For example, several recent studies have demonstrated that requiring participants to perform a concurrent demanding task can effectively eliminate the ability of exogenous cues to capture attention (Santangelo et al., 2007; Santangelo, Finoia, Raffone, Olivetti Belardinelli, & Spence, 2008; Santangelo & Spence, 2008; Theeuwes, 1991; Yantis & Jonides, 1990). Two of these studies, for instance, employed central-arrows as 100% predictive cues in a target detection task, while also deploying abrupt visual onsets as exogenous cues (Theeuwes, 1991; Yantis & Jonides, 1990), and found that the abrupt visual onsets had no effect on performance. Yet a different study by Van der Lubbe and Postma (2005) used more eccentric (peripheral) exogenous cues and obtained evidence to the contrary, where effects of the abrupt visual onsets were observed even when attention was engaged. Thus, there appears to be evidence indicating that under some circumstances exogenous cuing effects remain, while under others these effects are eliminated. While these experiments often employ a demanding central task, the question remains as to why opposing findings have been observed. Importantly, the answer to this question should