Stimulus-response compatibility in representational space

• Published in: Neuropsychologia Vol. 36; no. 8; pp. 731 - 735
• Main Authors: Bächtold, Daniel, Baumüller, Martin, Brugger, Peter
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.1998; Elsevier Science
• Subjects: Adolescent; Adult; Anatomical correlates of behavior; Behavioral psychophysiology; Biological and medical sciences; choice reaction time task; Cues; Functional Laterality - physiology; Fundamental and applied biological sciences. Psychology; Humans; Male; number processing; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Reaction Time - physiology; representational neglect; SNARC effect; Space Perception - physiology; Spatial S-R compatibility; choice reaction time task; representational neglect; Spatial S-R compatibility; number processing; SNARC effect; Space; Human; Hemisphere dominance; Number; Mental representation; Choice reaction time; Information processing; Cognition; Compatibility; Laterality; Response stimulus relation
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/S0028-3932(98)00002-5

Spatial stimulus—response (S-R) compatibility designates the observation that speeded reactions to unilateral stimuli are faster for the hand ipsilateral than for the hand contralateral to the sensory hemifield containing the stimulus. In two experiments involving presentation of the numbers 1 to 11 in the center of the visual field we show (1) a left-hand reaction time (RT) advantage for numerals <6 and a right-hand advantage for those >6 for subjects who conceive of the numbers as distances on a ruler, and (2) a reversal of this RT advantage for subjects who conceive of them as hours on a clock face. While the results in the first task (RULER) replicate a robust finding from the neuropsychology of number processing (the ‘‘SNARC effect’’) those in the second task (CLOCK) show that extension of the number scale from left to right in representational space cannot be the decisive factor for the observed interaction between hand and number size. Taken together, the findings in the two tasks are best accounted for in terms of an interaction between lateralized mental representations and lateralized motor outputs (i.e. an analog of traditional spatial S-R compatibility effects in representational space). We discuss potential clinical applications of the two tasks in patients with neglect of representational space.