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Directional and amplitude error in open-loop aimed movements: Laterality effects
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DIRECTIONAL AND AMPLITUDE ERROR IN OPEN-LOOP AIMED MOVEMENTS: LATERALITY EFFECTS DIAZ, G. AND GUIARD, Y. Department of Experimental Psychobiology, I n s t i t u t e of Neurophysiology and Psychophysiology, CNRS, INP.03, 31 ch. J. A i g u i e r , BP 71, 13277 Marseille C~dex 9, France In a previous study I where subjects had to perform a f a s t aimed movement without v i s i o n of t h e i r active limb, we reported that right-handers manifest a smaller spatial constant e r r o r when using t h e i r l e f t - n o n dominant, rather than the right-dominant hand. The subjects of the present experiment - r i g h t - h a n d e r s performed a s i m i l a r task (single-handed pointing at a punctual visual target appearing e i t h e r on the l e f t or on the r i g h t of the device, without visual feedback), but the movement t r a j e c t o r y was tangential - r a t h e r than perpendicular- to the t a r g e t . This allowed the separate measurement of movement accuracy in terms of amplitude and d i r e c t i o n . The target was presented 183 mm away from the centrally
located s t a r t i n g p o i n t , and 25 ° e i t h e r to the r i g h t or to the l e f t of the
s a g i t t a l axis of the target plane, at random. For each hand i p s i v e r s i v e movements (e.g. l e f t hand toward the l e f t target) were f a s t e r than contraversive movements (e.g. l e f t hand toward the r i g h t t a r g e t ) , at the cost, however, of a greater variable error both f o r amplitude and d i r e c t i o n . The r i g h t hand was f a s t e r (MT = 112 ms) than the l e f t hand (MT = 130 ms), without any difference in variable errors. However, the l e f t hand was more accurate than the r i g h t in terms of constant e r r o r , both f o r the amplitude and d i r e c t i o n of movement. These results are discussed, in the l i g h t of current theories of movement control 2, 3, in terms of the snecialized roles of the l e f t and r i g h t limbs of r i g h t - h a n d e r s .
REFERENCES I. Guiard, Y., Diaz, G. and Beaubaton, D., Neuropsychol., 21 (1983) 111. 2. Schmidt, R.A., Zelaznik, H., Hawkins, B., Frank, J.S. and Quinn, J.T. Jr., Psychol. Rev., 86 (1979) 415. 3. Meyer, D., Smith,K. and Wright, C., Psychol. Rev., 89 (1982) 449. '
DIRECTIONAL AND AMPLITUDE ERROR IN OPEN-LOOP AIMED MOVEMENTS: LATERALITY EFFECTS DIAZ, G. AND GUIARD, Y. Department of Experimental Psychobiology, I n s t i t u t e of Neurophysiology and Psychophysiology, CNRS, INP.03, 31 ch. J. A i g u i e r , BP 71, 13277 Marseille C~dex 9, France In a previous study I where subjects had to perform a f a s t aimed movement without v i s i o n of t h e i r active limb, we reported that right-handers manifest a smaller spatial constant e r r o r when using t h e i r l e f t - n o n dominant, rather than the right-dominant hand. The subjects of the present experiment - r i g h t - h a n d e r s performed a s i m i l a r task (single-handed pointing at a punctual visual target appearing e i t h e r on the l e f t or on the r i g h t of the device, without visual feedback), but the movement t r a j e c t o r y was tangential - r a t h e r than perpendicular- to the t a r g e t . This allowed the separate measurement of movement accuracy in terms of amplitude and d i r e c t i o n . The target was presented 183 mm away from the centrally
located s t a r t i n g p o i n t , and 25 ° e i t h e r to the r i g h t or to the l e f t of the
s a g i t t a l axis of the target plane, at random. For each hand i p s i v e r s i v e movements (e.g. l e f t hand toward the l e f t target) were f a s t e r than contraversive movements (e.g. l e f t hand toward the r i g h t t a r g e t ) , at the cost, however, of a greater variable error both f o r amplitude and d i r e c t i o n . The r i g h t hand was f a s t e r (MT = 112 ms) than the l e f t hand (MT = 130 ms), without any difference in variable errors. However, the l e f t hand was more accurate than the r i g h t in terms of constant e r r o r , both f o r the amplitude and d i r e c t i o n of movement. These results are discussed, in the l i g h t of current theories of movement control 2, 3, in terms of the snecialized roles of the l e f t and r i g h t limbs of r i g h t - h a n d e r s .
REFERENCES I. Guiard, Y., Diaz, G. and Beaubaton, D., Neuropsychol., 21 (1983) 111. 2. Schmidt, R.A., Zelaznik, H., Hawkins, B., Frank, J.S. and Quinn, J.T. Jr., Psychol. Rev., 86 (1979) 415. 3. Meyer, D., Smith,K. and Wright, C., Psychol. Rev., 89 (1982) 449. '