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Previous research has shown that visual attention can be directed to a spatial location in 2 qualitatively different ways. Attention can be allocated endogenously in response to centrally presented precues, or it can be captured exogenously by a visual stimulus with an abrupt onset. It has been suggested that exogenous orienting of attention is an automatic(More)
Many studies of covert orienting of visual attention in response to informative pre-cues have focused on the spatial distribution of improved or impaired performance. One can find at least four different models in the literature, each describing a different distribution: the fixed gradient spotlight; the zoom lens spotlight; the hemifield activation(More)
Jolicoeur, Ullman, and MacKay (1986) showed that the time to confirm that two dots are on the same curve increases monotonically, but nonlinearly, as the curve distance between the two dots increases. These displays contained two curves and two dots. On same trials, the two dots were on the same curve (target curve), while the other curve served as a foil(More)
In two experiments, we examined the effect of timing conditions on the magnitude of gender differences in performance on the Mental Rotations Test (MRT). In Experiment 1, each of 196 females and 119 males was administered the MRT via a Microsoft PowerPoint presentation in one of five timing conditions (15, 20, 25, 30, and 40 sec). The participants were(More)
A popular metaphor for visual attention is that of a spotlight that enhances perceptual processing within its beam. Many studies on the orienting of visual attention have addressed whether the beam is a unified structure or whether it can be split between noncontiguous locations in space. Although most of the evidence favors the unified model, U. Castiello(More)
The time required to determine that two dots occur on the same curve in a visual display increases with increasing interdot curve distance. McCormick and Jolicoeur (1991) presented a model of visual curve tracing in which a local operator with a variable size receptive field tracks the curve segment intervening the two dots. In this model, human response(More)
How is attention distributed over visual space when an observer expects a target to occur at one of several possible locations? Two experiments sought to understand the source of the conflict between studies leading to the notions of hemifield activation (Hughes and Zimba 1985) and attentional gradients (Downing and Pinker 1985; Shulman et al. 1985, 1986).(More)
There is debate over the mechanisms that govern the orienting of attention. Some argue that the enhanced performance observed at a cued location is the result of increased perceptual sensitivity or preferential access to decision-making processes. It has also been suggested that these effects may be the result of trades in speed for accuracy on the part of(More)
McCormick and Jolicoeur's (1991; 1994) zoom lens model of visual curve tracing proposes that curve tracing involves tracking a curve with a variable size local operator. Unspecified in their model is how the executive function guiding the processing field of this operator initially knows which direction to trace. An experiment was conducted to determine(More)
The early election call in the fall of 2000 provided the perfect opportunity to study the impact the Internet has had on election campaigning in Canada. With the explosion of use the Net has seen since the 1997 general election, Canadian federal parties stood at the threshold of a new age in election campaigning. Pundits such as Rheingold (1993) have argued(More)