TY  - JOUR
A1  - Schwarz, Wolfgang
A1  - Keus, I. M.
T1  - Moving the eyes along the mental number line : comparing SNARC effects with saccadic and manual responses
N2  - Bimanual parity judgments about numerically small (large) digits are faster with the left (right) hand, even though parity is unrelated to numerical magnitude per se (the SNARC effect; Dehaene, Bossini, & Giraux, 1993). According to one model, this effect reflects a space-related representation of numerical magnitudes (mental number line) with a genuine left-to-right orientation. Alternatively, it may simply reflect an overlearned motor association between numbers and manual responses-as, for example, on typewriters or computer keyboards-in which case it should be weaker or absent with effectors whose horizontal response component is less systematically associated with individual numbers. Two experiments involving comparisons of saccadic and manual parity judgment tasks clearly support the first view; they also establish a vertical SNARC effect, suggesting that our magnitude representation resembles a number map, rather than a number line
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Keus, I. M.
A1  - Jenks, C.
A1  - Schwarz, Wolfgang
T1  - Psychophysiological evidence that the SNARC effect has a functional locus in a response selection stage
N2  - When participants judge the parity of visually presented digits, left-hand responses are faster for numerically small numbers, whereas right-hand responses are faster for large numbers [SNARC effect; S. Dehaene, S. Bossini, P. Giraux, The mental representation of parity and number magnitude. J. Exp. Psychol. Gen., 122, (1993) 371-396]. The present study aimed to find more direct evidence for the functional locus of this effect by recording brain waves while participants performed speeded parity judgments giving manual responses. Our results show clear and robust SNARC effects in the response-locked event-related potentials (ERPs) compared to the stimulus-locked ERPs, confirming that the SNARC effect arises during response-related rather than stimulus-related processing stages. Further analyses of lateralized readiness potentials strongly suggest that the SNARC effect begins to emerge in a response-related stage prior to response preparation and execution, more specifically, in a response selection stage. (c) 2005 Elsevier B.V All rights reserved
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Keus, I. M.
A1  - Schwarz, Wolfgang
T1  - Searching for the functional locus of the SNARC effect : evidence for a response-related origin
Y1  - 2005
ER  -