Academic journal article Attention, Perception and Psychophysics

Facilitation by Exogenous Attention for Static and Dynamic Gestalt Groups

Academic journal article Attention, Perception and Psychophysics

Facilitation by Exogenous Attention for Static and Dynamic Gestalt Groups

Article excerpt

Published online: 9 May 2014

# Psychonomic Society, Inc. 2014

Abstract Attentional mechanisms allow the brain to selectively allocate its resources to stimuli of interest within the huge amount of information reaching its sensory systems. The voluntary component of attention, endogenous attention, can be allocated in a flexible manner depending on the goals and strategies of the observer. On the other hand, the reflexive component, exogenous attention, is driven by the stimulus. Here, we investigated how exogenous attention is deployed to moving stimuli that form distinct perceptual groups. We showed that exogenous attention is deployed according to a reference frame that moves along with the stimulus. Moreover, in addition to the cued stimulus, exogenous attention is deployed to all elements forming a perceptual group. These properties provide a basis for the efficient deployment of exogenous attention under ecological viewing conditions.

Keywords Object-based attention . Space-based attention . Attentional capture

The visual system receives a staggering amount of informa- tion. Given its limited resources, it needs to filter out irrelevant information while selecting information of interest for further processing. Attention plays a crucial role in the filtering and selection of information. Attentional processes can be classi- fied into two broad types (e.g., Cheal & Lyon, 1991;Egeth& Yantis, 1997; Jonides, 1981; Müller & Rabbitt, 1989; Nakayama & Mackeben, 1989; Posner, 1980; Weichselgartner & Sperling, 1987): Endogenous attention refers to a relatively slow component, whereby observers direct their attention by voluntary control to a stimulus or location of choice. Exogenous attention is a relatively fast component through which attention is directed as a reflexive response to the stimulus. For example, the onset of a flash at a peripheral location reflexively summons attention to this lo- cation. Since endogenous attention is under voluntary control, it can be flexibly directed, depending of how targets of interest are defined-for example, by color, location, shape, seman- tics, and so forth (Barrett, Bradshaw, & Rose, 2003;Müller& Rabbitt, 1989). On the other hand, because exogenous atten- tion is driven by the stimulus, rather than by voluntary control, where it is directed to may not be as flexible as with endog- enous attention.

Various lines of evidence indicate that exogenous attention can be directed to retinotopic and spatiotopic locations as well as to "objects" (e.g., Boi, Vergeer, Ogmen, & Herzog, 2011; Brown, Breitmeyer, Leighty, & Denney, 2006;Egly,Driver,& Rafal, 1994; Egly, Rafal, Driver, & Starrveveld, 1994;Iani, Nicoletti, Rubichi, & Umiltà, 2001;Lamy&Egeth,2002; Lamy & Tsal, 2000; Moore, Yantis, & Vaughan, 1998;Reppa, Schmidt, & Leek, 2012; Theeuwes, Mathôt, & Grainger, 2013; Vecera, 1994). To demonstrate the latter effect, Egly, Driver, and Rafal (1994) presented two adjacent rectangles and cued one edge of one of the rectangles. When Reaction Times (RTs) were compared between two equidistant targets, one within the cued rectangle and the other within the uncued rectangle, it was found that they were significantly shorter to the target within the cued rectangle.1 This was interpreted as exogenous attention being summoned to the whole cued ob- ject. According to an alternative explanation, once exogenous attention is attracted to a location within an object, it automat- ically spreads to the entire object.

Both of these interpretations are based on the concept of an "object"; however, the exact definition of the "object" concept remains difficult (e.g., Humphreys & Riddoch, 2007; Kasai, Moriya, & Hirano, 2011;Marr,1982; Pinna, 2014; Scholl, 2001). For example, one may define an object by contour closure. According to this definition, the allocation or spread- ing of attention would be limited by the contours of the stimulus. …

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