There is much anecdotal suggestion of improved visual skills in congenitally deaf individuals. However, this claim has only been met by mixed results from careful investigations of visual skills in deaf individuals. Psychophysical assessments of visual functions have failed, for the most part, to validate the view of enhanced visual skills after deafness. Only a few studies have shown an advantage for deaf individuals in visual tasks. Interestingly, all of these studies share the requirement that participants process visual information in their peripheral visual field under demanding conditions of attention. This work has led us to propose that congenital auditory deprivation alters the gradient of visual attention from central to peripheral field by enhancing peripheral processing. This hypothesis was tested by adapting a search task from Lavie and colleagues in which the interference from distracting information on the search task provides a measure of attentional resources. These authors have established that during an easy central search for a target, any surplus attention remaining will involuntarily process a peripheral distractor that the subject has been instructed to ignore. Attentional resources can be measured by adjusting the difficulty of the search task to the point at which no surplus resources are available for the distractor. Through modification of this paradigm, central and peripheral attentional resources were compared in deaf and hearing individuals. Deaf individuals possessed greater attentional resources in the periphery but less in the center when compared to hearing individuals. Furthermore, based on results from native hearing signers, it was shown that sign language alone could not be responsible for these changes. We conclude that auditory deprivation from birth leads to compensatory changes within the visual system that enhance attentional processing of the peripheral visual field.

This paper reports a series of four experiments that established a negative compatibility effect (NCE) by which compatible distractors led to slower and less accurate target performance than did incompatible ones (Experiment 1). This effect is interpreted as an early perceptual effect that delays the attribution of visual attention over the target location in the compatible condition. This view predicted that the NCE should be observed only when attention has to be selectively attributed to the target location. In Experiments 2 and 3, this prediction was tested by manipulating the perceptual load in the display. Highperceptual load displays are lrnown to require selective attention (Lavie, 1995). Accordingly,reliable NCEs were observed when high-load displays were used. In contrast, reduced NCEs were found in displays that did not require selective attention. Experiment 4 established that the manifestation of the NCEwas influenced by low-levelvisual cues, such as brightness and contrast. Overall,these experiments indicated that the NCE can be understood as an early perceptual effect, which arises from a conflict between the cues that guide the distribution of attention when the task requires selective attention.Response to a target shape is facilitated by the presence of distractors associated with the same response (compatible distractors), as compared with distractors associated with a competing response (incompatible distractors). Participants presented with a display containing two shapes, one blue and one red, are typically slower and less accurate at identifying the blue shape as a square when the red shape is a diamond rather than a square. This effect will hereafter be termed the positive compatibility effect (PCE). Although the Stroop effect and the flanker compatibility effect are probably the most well-known examples of positive compatibility effects, compatibility effects are so pervasive that they are observed across various tasks and stimuli (see Kornblum & Lee, 1995, for an exhaustive review of the different kinds of compatibility effects). Surprisingly, in a series of experiments on selective attention that manipulated a variant of the flanker compatibility effect, Briand (1994) found, under certain conditions, a negative compatibility effect (NCE). In the experiment of interest, two compound letters were presented, one in red and the other in blue ( Figure I). The participants were required to identify letters at the local level of the blue group while ignoring the red group. The participants were 29 msec slower to identify the local blue letters when the identity of the global red letter was compatible than when it was incompatible. Similarly, in a series of experiments that manipulated the Stroop effect and the Garner effect, Van Leeuwen and Bakker (1995) reported NCEs. In their experiments, participants were presented with two shapes, each with a local indentation and a global form. They were asked to decide whether the local indentation of the target shape was a triangle or a square, while ...

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