Since the seminal observation of the SNARC effect by Dehaene, Bossini, and Giraux [(1993) Journal of Experimental Psychology: General, 122(3), 371-396] several studies have indicated the existence of an intrinsic-automatic spatial coding of number magnitudes. In the first part of this chapter we summarize recent work with healthy participants and expand on this original claim. Some of our evidence can be used to support a theory of spatial mapping of mental numbers onto mental space where smaller numbers are associated with the left and larger numbers with the right side of space. In the second part of the chapter we review investigations of spatial neglect and relate them to "small number neglect", which initially seemed to provide crucial support for a tight link between mechanisms of spatial attentional orienting and the mental manipulation of number magnitudes [Zorzi et al. (2002). Nature 417, 138-139]. We will see that although left unilateral neglect after right-brain damage can occur in both visual and number space, recent behavioral dissociations, controlled studies and neuroanatomical correlations have consistently confirmed the functional dissociation of these two deficits and the absence of a causal effect of lateralized spatial-attentional impairments on numerical cognition. Finally, based on recent data gathered from experiments specifically designed to generate a mismatch in the "default" association of small numbers with the left side of space and large numbers with the right side of space, we argue that the pathological deviation toward larger numbers shown by right-brain-damaged patients in the bisection of number intervals may not arise from a basic spatial-attentional impairment. Taken together, these findings suggest that to assume a close phenomenological, functional and anatomical equivalence between orienting in visual space and orienting in representational number space could be partially misleading. It is concluded that careful reassessment of empirical evidence and consideration of the combined contributions of sensorimotor, conceptual, and working memory factors to mathematical cognition may provide a more coherent understanding of the adaptive interaction between spatial and mathematical thought.
Neglect "Around the Clock": Dissociating Number and Spatial Neglect in Right Brain Damage
M. Aiello;
2011-01-01
Abstract
Since the seminal observation of the SNARC effect by Dehaene, Bossini, and Giraux [(1993) Journal of Experimental Psychology: General, 122(3), 371-396] several studies have indicated the existence of an intrinsic-automatic spatial coding of number magnitudes. In the first part of this chapter we summarize recent work with healthy participants and expand on this original claim. Some of our evidence can be used to support a theory of spatial mapping of mental numbers onto mental space where smaller numbers are associated with the left and larger numbers with the right side of space. In the second part of the chapter we review investigations of spatial neglect and relate them to "small number neglect", which initially seemed to provide crucial support for a tight link between mechanisms of spatial attentional orienting and the mental manipulation of number magnitudes [Zorzi et al. (2002). Nature 417, 138-139]. We will see that although left unilateral neglect after right-brain damage can occur in both visual and number space, recent behavioral dissociations, controlled studies and neuroanatomical correlations have consistently confirmed the functional dissociation of these two deficits and the absence of a causal effect of lateralized spatial-attentional impairments on numerical cognition. Finally, based on recent data gathered from experiments specifically designed to generate a mismatch in the "default" association of small numbers with the left side of space and large numbers with the right side of space, we argue that the pathological deviation toward larger numbers shown by right-brain-damaged patients in the bisection of number intervals may not arise from a basic spatial-attentional impairment. Taken together, these findings suggest that to assume a close phenomenological, functional and anatomical equivalence between orienting in visual space and orienting in representational number space could be partially misleading. It is concluded that careful reassessment of empirical evidence and consideration of the combined contributions of sensorimotor, conceptual, and working memory factors to mathematical cognition may provide a more coherent understanding of the adaptive interaction between spatial and mathematical thought.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
