Tradeoff between manual response speed and pursuit accuracy revealed by a deadline procedure

Effects of internally directed cognition on smooth pursuit eye movements: A systematic examination of perceptual decoupling

Eye behavior differs between internally and externally directed cognition and thus is indicative of an internal versus external attention focus. Recent work implicated perceptual decoupling (i.e., eye behavior becoming less determined by the sensory environment) as one of the key mechanisms involved in these attention-related eye movement differences. However, it is not yet understood how perceptual decoupling depends on the characteristics of the internal task. Therefore, we systematically examined effects of varying internal task demands on smooth pursuit eye movements. Specifically, we evaluated effects of the internal workload (control vs. low vs. high) and of internal task (arithmetic vs. visuospatial). The results of multilevel modelling showed that effects of perceptual decoupling were stronger for higher workload, and more pronounced for the visuospatial modality. Effects also followed a characteristic time-course relative to internal operations. The findings provide further support of the perceptual decoupling mechanism by showing that it is sensitive to the degree of interference between external and internal information.

Visual selective attention and the control of tracking eye movements: a critical review

People’s eyes are directed at objects of interest with the aim of acquiring visual information. However, processing this information is constrained in capacity, requiring task-driven and salience-driven attentional mechanisms to select few among the many available objects. A wealth of behavioral and neurophysiological evidence has demonstrated that visual selection and the motor selection of saccade targets rely on shared mechanisms. This coupling supports the premotor theory of visual attention put forth more than 30 years ago, postulating visual selection as a necessary stage in motor selection. In this review, we examine to which extent the coupling of visual and motor selection observed with saccades is replicated during ocular tracking. Ocular tracking combines catch-up saccades and smooth pursuit to foveate a moving object. We find evidence that ocular tracking requires visual selection of the speed and direction of the moving target, but the position of the motion signal may not coincide with the position of the pursuit target. Further, visual and motor selection can be spatially decoupled when pursuit is initiated (open-loop pursuit). We propose that a main function of coupled visual and motor selection is to serve the coordination of catch-up saccades and pursuit eye movements. A simple race-to-threshold model is proposed to explain the variable coupling of visual selection during pursuit, catch-up and regular saccades, while generating testable predictions. We discuss pending issues, such as disentangling visual selection from preattentive visual processing and response selection, and the pinpointing of visual selection mechanisms, which have begun to be addressed in the neurophysiological literature.

The Role of Time Constraints in Athletes' Egocentric Mental Rotation Performance

A selective effect of motor expertise on mental rotation is revealed by a high correlation between the performance of sports experts and ability on a mental rotation task. Evidence is shown by studies involving a spatial factor, such as image interference or a movement constraint. Alternatively, the time constraint, as another performance factor, is considered critical in the effect of sport expertise on mental rotation. Three experiments were conducted to examine the role of time constraints in egocentric mental rotation and the stage performance of athletes (divers) and nonathletes. In Experiment 1, an egocentric mental rotation task in an untimed condition was conducted, and reaction times (RTs), error rates (ERs), RTs at 0 °, and mental rotation speed were assessed. The results indicated that divers outperformed nonathletes in terms of RT, as well as perceptual and decision stages and rotation stages. Experiments 2 and 3 added a relative time constraint (subtracting 1/2 SD of all the subjects' RT from the M of each group's RT) and an absolute time constraint (subtracting 1/2 SD of all the subjects' RT from the M of all the subjects' RT) to the task, respectively. Superior RT and lower ER were observed for the divers in the time constraint condition. Moreover, the results illustrated that divers were faster than nonathletes in both stages when facing time pressure. In general, the present study has, for the first time, confirmed the role of time in the relationship between sports expertise and mental rotation.

Role of motor execution in the ocular tracking of self-generated movements

When human observers track the movements of their own hand with their gaze, the eyes can start moving before the finger (i.e., anticipatory smooth pursuit). The signals driving anticipation could come from motor commands during finger motor execution or from motor intention and decision processes associated with self-initiated movements. For the present study, we built a mechanical device that could move a visual target either in the same direction as the participant's hand or in the opposite direction. Gaze pursuit of the target showed stronger anticipation if it moved in the same direction as the hand compared with the opposite direction, as evidenced by decreased pursuit latency, increased positional lead of the eye relative to target, increased pursuit gain, decreased saccade rate, and decreased delay at the movement reversal. Some degree of anticipation occurred for incongruent pursuit, indicating that there is a role for higher-level movement prediction in pursuit anticipation. The fact that anticipation was larger when target and finger moved in the same direction provides evidence for a direct coupling between finger and eye motor commands.