The speed-accuracy trade-off in manual prehension: effects of movement amplitude, object size and object width on kinematic characteristics

Abstract

Earlier studies have suggested that the size of an object to be grasped influences the time taken to complete a prehensile movement. However, the use of cylindrical objects in those studies confounded the effects of object size-extent orthogonal to the reach axis-and object width-extent along the reach axis. In separating these effects, the present study demonstrates that movement time is not affected by manipulation of object size, as long as the latter does not approach the maximal object size that can be grasped. Object width, on the other hand, is shown to exert a systematic influence on movement time: Smaller object widths give rise to longer movement times through a lengthening of the deceleration phase of the movement, thus reproducing the effect of target width on the kinematics of aiming movements. As in aiming, movement amplitude also affects the movement time in prehension, influencing primarily the acceleration phase (i.e. peak velocity attained). The effects of object width and movement amplitude were found to combine in a way predicted by Fitts' law, allowing a generalisation of the latter to the transport component in prehensile actions. With respect to the grasp component, both object size and object width are shown to affect peak hand aperture. Increasing object width thus lowers the spatial accuracy demands on the transport component, permitting a faster movement to emerge. At the same time, the hand opens to a larger grip in order to compensate for eventual directional errors that result.(ABSTRACT TRUNCATED AT 250 WORDS)

Modeling prehensile actions for the evaluation of Tangible User Interfaces

“…The work that is most similar to ours is that of Bootsma et al [2], who studied how prehensile movements are affected by movement amplitude, target size, and target width. The result of their work however, is not a model that describes the prehensile motion completely.…”

“…There are several other properties that may impact the model, such as the width [2] and the weight of the artifact, whether it is a container that contains a liquid that may be spilled, the target's fragility, and others. While we believe that these factors may play a role in the model's behavior, we also believe that most of the artifacts that are presented in TUIs are well represented by our choice of the tested artifact.…”

Visual layout modulates Fitts’s law: The importance of first and last positions

“…It has been the focus of more than 200 published studies (nearly 150 of which have been published in the last 10 years). The equation has been shown to hold with prehension movements (e.g., Bootsma, Marteniuk, MacKenzie, & Zaal, 1994), mouse cursor movements (e.g., Lin, Radwin, & Vanderheiden, 1992), rotational movements (e.g., Abrams, Meyer, & Kornblum, 1990), head movements (e.g., Jagacinksi & Monk, 1985), and foot movements (e.g., Hoffmann, 1991). The equation holds underwater (Kerr, 1973), in near zero-gravity environments (Jungling, Bock, & Girgenrath, 2002), with microscopic targets (Langolf, Chaffin, & Foulke, 1976), with imaginary movements (Sirigu et al, 1996), and with targets that have illusory IDs (e.g., Fischer, 2001).…”

Ergonomics of Prehensility in Pushing and Pulling Motions: An Anatomical and Biomechanical Overview

“…The weight of the object is normally estimated based on available visual information It means that the object can be properly "nestled" in the "containing capacity" of the hand. The prehensile adaptability of the hand [11,12] corresponds with the unlimited variability in size and shape of objects and instruments. It has been shown that increasing object width lowers the spatial accuracy demands on an object, permitting a faster movement to emerge.…”