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Four experiments were conducted to investigate the role of stimulus-driven and goal-driven control in saccadic eye movements. Participants were required to make a speeded saccade toward a predefined target presented concurrently with multiple nontargets and possibly 1 distractor. Target and distractor were either equally salient (Experiments 1 and 2) or not (Experiments 3 and 4). The results uniformly demonstrated that fast eye movements were completely stimulus driven, whereas slower eye movements were goal driven. These results are in line with neither a bottom-up account nor a top-down notion of visual selection. Instead, they indicate that visual selection is the outcome of 2 independent processes, one stimulus driven and the other goal driven, operating in different time windows.

ABSTRACT-A salient event in the visual field tends to attract attention and the eyes. To account for the effects of salience on visual selection, models generally assume that the human visual system continuously holds information concerning the relative salience of objects in the visual field. Here we show that salience in fact drives vision only during the short time interval immediately following the onset of a visual scene. In a saccadic target-selection task, human performance in making an eye movement to the most salient element in a display was accurate when response latencies were short, but was at chance when response latencies were long. In a manual discrimination task, performance in making a judgment of salience was more accurate with brief than with long display durations. These results suggest that salience is represented in the visual system only briefly after a visual image enters the brain.A salient object tends to attract attention and often initiates a subsequent eye movement. This finding has been replicated often and is well established (Itti & Koch, 2001;Theeuwes, Kramer, Hahn, & Irwin, 1998). It demonstrates that visual selection is very much influenced by the stimulus properties in the visual field. Current computational, functional, and neurophysiological models of visual selection account for stimulusdriven effects by assuming that the brain possesses a salience map, a topographical representation of the relative distinctiveness of all objects in the visual field

Two experiments were conducted to investigate the effects of saliency on saccadic target selection as a function of time. Participants were required to make a speeded saccade towards a target defined by a unique orientation presented concurrently with multiple nontargets and one distractor. Target and distractor were equally salient within the orientation dimension but varied in saliency in the colour dimension. Within the colour dimension, the target presented could be more, equally, or less salient than the distractor. The results showed that saliency played a large role early during processing while no effects of saliency were found in later processing. Results are discussed in terms of models on visual selection.Imagine yourself in the library looking for a specific book. You know the name of the author and the title, but you have no idea what the book looks like. Assume that on an average day, it takes you about 5 minutes, measured from the point in time you walk into the library, to find an average shaped and coloured book by title and author. It might take you only 1 minute when the book you are looking for happens to be bright red and very large. Many people believe that if a stimulus is sufficiently salient, it will pop out of a visual scene. In turn, they assume that search performance is better when the salient stimulus is the target of search, as compared to when a nonsalient item is the target of search.Most researchers in the area of visual selective attention assume that covert (attentional) selection and overt (oculomotor) selection are at least partly determined by stimulus salience, or more generally speaking by the stimulus properties in the visual field (Cave & Wolfe, 1990;Itti & Koch, 2000;Koch & Ullman, 1985; Theeuwes, 1991Theeuwes, , 1992Theeuwes, , 1994Wolfe, 1994;Wolfe, Cave, & Franzel, 1989). To incorporate this idea, recent models of visual selection have proposed that visual selection is determined by the output provided by some common salience map. Within a salience map, the location with the highest activation level corresponds to the most salient location at that point in time and

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