Performing a cognitive task while maintaining upright stance can lead to increased or reduced body sway depending on tasks and experimental conditions. Because greater sway is commonly taken to indicate loosened postural control, and vice versa, the precise impact of cognitive load on postural stability has remained unclear. In much of the large…

The aim of this study was to investigate the perception of possibilities for action (i.e., affordances) that depend on one's movement capabilities, and more specifically, the passability of a shrinking gap between converging obstacles. We introduce a new optical invariant that specifies in intrinsic units the minimum locomotor speed needed to…

Research on bimanual coordination of hand movements has identified several loci of bimanual interference, including interference because of programming different movement parameters or selecting different targets for the two hands. This study investigates the extent and origin of interference when participants execute bimanual actions with tools.…

This investigation examined how children and adults negotiate a challenging perceptual-motor problem with significant real-world implications--bicycling across two lanes of opposing traffic. Twelve- and 14-year-olds and adults rode a bicycling simulator through an immersive virtual environment. Participants crossed intersections with continuous…

The ability to coordinate serial processing of multiple items is crucial for fluent reading but is known to be impaired in dyslexia. To investigate this impairment, we manipulated the orthographic and phonological similarity of adjacent letters online as dyslexic and nondyslexic readers named letters in a serial naming (RAN) task. Eye movements…

People often perform actions that involve a direct physical coupling with another person, such as when moving furniture together. Here, we examined how people successfully coordinate such actions with others. We tested the hypothesis that dyads amplify their forces to create haptic information to coordinate. Participants moved a pole (resembling a…

According to an action-specific account of perception, the perceived speed of a ball can be a function of the ease to block the ball. Balls that are easier to stop look like they are moving slower than balls that are more difficult to stop. This was recently demonstrated with a modified version of the classic computer game Pong (Witt & Sugovic,…

We investigated the causal role of executive control functions in the production of brief time intervals by means of a concurrent task paradigm. To isolate the influence of executive functions on timing from motor coordination effects, we dissociated executive load from the number of effectors used in the dual task situation. In 3 experiments,…

"Groove" is often described as the experience of music that makes people tap their feet and want to dance. A high degree of consistency in ratings of groove across listeners indicates that physical properties of the sound signal contribute to groove (Madison, 2006). Here, correlations were assessed between listeners' ratings and a number…

Reaching to targets in space requires the coordination of eye and hand movements. In two experiments, we recorded eye and hand kinematics to examine the role of gaze position at target onset on eye-hand coordination and reaching performance. Experiment 1 showed that with eyes and hand aligned on the same peripheral start location, time lags…

We address the complex relationship between the stability, variability, and adaptability of psychological systems by decomposing the global variance of serial performance into two independent parts: the local variance (LV) and the serial correlation structure. For two time series with equal LV, the presence of persistent long-range correlations…

According to ideomotor theories, perceiving action effects produced by others triggers corresponding action representations in the observer. We tested whether this principle extends to actions performed by externally controlled limbs and tools. Participants performed a go-no-go version of a spatial compatibility task in which their own actions…

Predicting the consequences of actions is fundamental for skilled motor behavior. We investigated whether motor prediction is influenced by the fact that some movements are easier to perform and stabilize than others. Twelve subjects performed a bimanual rhythmical task either symmetrically or asymmetrically (the latter being more difficult and…

Primary somatosensory maps in the brain represent the body as a discontinuous, fragmented set of two-dimensional (2-D) skin regions. We nevertheless experience our body as a coherent three-dimensional (3-D) volumetric object. The links between these different aspects of body representation, however, remain poorly understood. Perceiving the body's…

Coordinated rhythmic movement is specifically structured in humans. Movement at 0[degrees] mean relative phase is maximally stable, 180[degrees] is less stable, and other coordinations can, but must, be learned. Variations in perceptual ability play a key role in determining the observed stabilities so we investigated whether stable movements can…