Abstract
The role of binocular vision in grasping has frequently been assessed by measuring the effects on grasp kinematics of covering one eye. These studies have typically used three or fewer objects presented at three or fewer distances, raising the possibility that participants learn the properties of the stimulus set. If so, even relatively poor visual information may be sufficient to identify which object/distance configuration is presented on a given trial, in effect providing an additional source of depth information. Here we show that the availability of this uncontrolled cue leads to an underestimate of the effects of removing binocular information, and therefore to an overestimate of the effectiveness of the remaining cues. We measured the effects of removing binocular cues on visually open-loop grasps using (1) a conventional small stimulus-set, and (2) a large, pseudo-randomised stimulus set, which could not be learned. Removing binocular cues resulted in a significant change in grip aperture scaling in both conditions: peak grip apertures were larger (when reaching to small objects), and scaled less with increases in object size. However, this effect was significantly larger with the randomised stimulus set. These results confirm that binocular information makes a significant contribution to grasp planning. Moreover, they suggest that learned stimulus information can contribute to grasping in typical experiments, and so the contribution of information from binocular vision (and from other depth cues) may not have been measured accurately.
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Notes
In psychophysical studies, using the same stimuli as this paper, we have found that just-noticeable differences in object depth under monocular viewing are typically 4–6 mm (Watt et al. 2008).
In principle this analysis applies to the effects of removing any depth cue, but we concentrate on binocular cues here.
Jackson et al. (1997) reported peak grip apertures in terms of the angle formed by the finger, wrist and thumb markers. We estimated the conversion into millimetres using the average hand size of our observers.
References
Bingham GP, Pagano CC (1998) The necessity of a perception action approach to definite distance perception: monocular distance perception for reaching. J Exp Psychol Hum Percept Perform 24:145–168
de Berg M, van Kreveld M, Overmars M, Schwarzkopf O (2000) Computational geometry: algorithms and applications, 2nd edn. Springer, New York
Ernst MO, Banks MS (2002) Humans integrate visual and haptic information in a statistically optimal fashion. Nature 415:429–433
Greenwald HS, Knill DC (2008) A comparison of visuomotor cue integration strategies for object placement and prehension. Vis Neurosci (published online, Cambridge University Press. doi:10.1017/S0952523808080668)
Harris CM, Wolpert DM (1998) Signal-dependent noise determines motor planning. Nature 394:780–784
Hillis JM, Watt SJ, Landy MS, Banks MS (2004) Slant from texture and disparity cues: optimal cue combination. J Vis 4:967–992
Holway AH, Boring EG (1941) Determinants of apparent visual size with distance variant. Am J Psychol 54:21–37
Jackson SR, Jones CA, Newport R, Pritchard C (1997) A kinematic analysis of goal-directed prehension movements executed under binocular, monocular, and memory-guided viewing conditions. Vis Cogn 4:113–142
Jakobson LS, Goodale MA (1991) Factors affecting higher-order movement planning: a kinematic analysis of human prehension. Exp Brain Res 86:199–208
Jeannerod M (1984) The timing of natural prehension movements. J Mot Behav 16:235–254
Jeannerod M (1988) The neural and behavioural organization of goal-directed movements. Clarendon Press, Oxford
Knill DC (2005) Reaching for visual cues to depth: the brain combines depth cues differently for motor control and perception. J Vis 5:103–115
Knill DC, Saunders JA (2003) Do humans optimally integrate stereo and texture information for judgments of surface slant? Vis Res 43:2539–2558
Künnapas T (1968) Distance perception as a function of available visual cues. J Exp Psychol 77:523–529
Loftus A, Servos P, Goodale MA, Mendarozqueta N, Mon-Williams M (2004) When two eyes are better than one in prehension: monocular viewing and end-point variance. Exp Brain Res 158:317–327
Marotta JJ, Goodale MA (2001) The role of familiar size in the control of grasping. J Cogn Neurosci 13:8–17
Marotta JJ, Kruyer A, Goodale MA (1998) The role of head movements in the control of manual prehension. Exp Brain Res 120:134–138
McIntosh R, Lashley G (2008) Matching boxes: familiar size influences action programming. Neuropsychologia 46:2441–2444
Melmoth DR, Grant S (2006) Advantages of binocular vision for the control of reaching and grasping. Exp Brain Res 17:371–388
O’Leary A, Wallach H (1980) Familiar size and linear perspective as distance cues in stereoscopic depth constancy. Percept Psychophys 27:131–135
Oruç I, Maloney LT, Landy (2003) Weighted linear cue combination with possibly correlated error. Vis Res 43:2451–2468
Schlicht EJ, Schrater PR (2007) Effects of visual uncertainty on grasping movements. Exp Brain Res 182:47–57
Sedgwick HA (1986) Space perception. In: Boff KR, Kaufman L, Thomas JP (eds) Handbook of perception and human performance. Sensory processes and perception, vol 1. Wiley, New York, pp 1–57
Servos P, Goodale MA, Jakobson LS (1992) The role of binocular vision in prehension: a kinematic analysis. Vis Res 3:1513–1521
Watt SJ, Bradshaw MF (2000) Binocular cues are important in controlling the grasp but not the reach in natural prehension movements. Neuropsychologia 38:1473–1481
Watt SJ, Keefe BD, Hibbard PB (2008) Visual uncertainty predicts grasping when monocular cues are removed but not when binocular cues are removed. J Vis 8:297
Wing AM, Turton A, Fraser C (1986) Grasp size and accuracy of approach in reaching. J Mot Behav 18:245–260
Acknowledgments
Supported by an Economic and Social Research Council PhD studentship to Bruce Keefe, and by the Engineering and Physical Sciences Research Council. Thanks to Matthew Elsby for help with data collection. Thanks to Paul Hibbard, Kevin MacKenzie, and two anonymous reviewers for helpful comments on the manuscript, and to Llewelyn Morris for technical support. Part of this work was presented at the Vision Sciences Society annual meeting, in May 2008.
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Keefe, B.D., Watt, S.J. The role of binocular vision in grasping: a small stimulus-set distorts results. Exp Brain Res 194, 435–444 (2009). https://doi.org/10.1007/s00221-009-1718-4
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DOI: https://doi.org/10.1007/s00221-009-1718-4