In two experiments we investigated the relationship between eye movements and performance in visual search tasks of varying difficulty. Experiment 1 provided evidence that a single process is used for search among static and moving items. Moreover, we estimated the functional visual field (FVF) from the gaze coordinates and found that its size…

Robust control of skilled actions requires the flexible combination of multiple sources of information. Here we examined the role of gaze during high-speed locomotor steering and in particular the role of feedback from the visible road edges. Participants were required to maintain one of three lateral positions on the road when one or both edges…

Responses are slower to targets appearing in recently inspected locations, an effect known as Inhibition of Return (IOR). IOR is typically viewed as the consequence of an involuntary mechanism that prevents reinspection of previously visited locations and thereby biases attention toward novel locations during visual search. For an inhibitory…

The purpose of this study was to examine the effects of expertise on motion anticipation. We conducted 2 experiments in which novices and expert pilots viewed simulated aircraft landing scenes. The scenes were interrupted by the display of a black screen and then started again after a forward or backward shift. The participant's task was to…

Locomoting through the environment typically involves anticipating impending changes in heading trajectory in addition to maintaining the current direction of travel. We explored the neural systems involved in the "far road" and "near road" mechanisms proposed by Land and Horwood (1995) using simulated forward or backward travel where participants…

Spivey, Grosjean, and Knoblich (2005) reported smoothly curved reaching movements, via computer-mouse tracking, which suggested a continuously evolving flow of distributed lexical activation patterns into motor movement during a phonological competitor task. For example, when instructed to click the "candy," participants' mouse-cursor trajectories…

M. J. Spivey, M. Grosjean, and G. Knoblich (2005) showed that in a phonological competitor task, participants' mouse cursor movements showed more curvature toward the competitor item when the competitor and target were phonologically similar than when the competitor and target were phonologically dissimilar. Spivey et al. interpreted this result…

When tracking moving objects in space humans usually attend to the objects' spatial locations and update this information over time. To what extent do surface features assist attentive tracking? In this study we asked participants to track identical or uniquely colored objects. Tracking was enhanced when objects were unique in color. The benefit…

A neural model is developed to explain how humans can approach a goal object on foot while steering around obstacles to avoid collisions in a cluttered environment. The model uses optic flow from a 3-dimensional virtual reality environment to determine the position of objects on the basis of motion discontinuities and computes heading direction,…

The authors examined observers steering through a series of obstacles to determine the role of active gaze in shaping locomotor trajectories. Participants sat on a bicycle trainer integrated with a large field-of-view simulator and steered through a series of slalom gates. Steering behavior was determined by examining the passing distance through…

The authors examined center-surround effects for motion perception in human observers. The magnitude of the motion aftereffect (MAE) elicited by a drifting grating was measured with a nulling task and with a threshold elevation procedure. A surround grating of the same spatial frequency, temporal frequency, and orientation significantly reduced…

After prolonged viewing of a slowly drifting or rotating pattern under strict fixation, the pattern appears to slow down and then momentarily stop. The authors show that grouping can slow down the process of "motion fading," suggesting that cortical configural form analysis interacts with the computation of motion signals during motion fading. The…

When 2 targets for pursuit eye movements move in different directions, the eye velocity follows the vector average (S. G. Lisberger & V. P. Ferrera, 1997). The present study investigates the mechanisms of target selection when observers are instructed to follow a predefined horizontal target and to ignore a moving distractor stimulus. Results show…

Performance in 2 versions of a computer-animated task was compared. Participants either indicated the time of arrival of a target that rolled off a horizontal surface and fell--hidden from view--onto a landing point (production task) or judged flight time on a rating scale (judgment task). As predicted, performance was significantly better in the…

The generalized optic acceleration cancellation (GOAC) theory of catching proposes that the path of a fielder running to catch a ball is determined by the attempt to satisfy 2 independent constraints. The 1st is to keep the angle of elevation of gaze to the ball increasing at a decreasing rate. The 2nd is to control the rate of horizontal rotation…