On the nature of near space: Effects of tool use and the transition to far space

Right hemisphere control of visuospatial attention in near space

“…This shift in bias is generally continuous, and the rate at which it occurs has been taken as an index of the extent, or "size," of near space. Indeed, this method has been used to show expansion of near space following tool use (Gamberini et al, 2008;Longo & Lourenco, 2006), contraction of near space when participants wear heavy wrist weights (Lourenco & Longo, 2009), and systematic inter-individual relations between the extent of near space and arm length (Longo & Lourenco, 2007) as well as claustrophobic fear (Lourenco et al, 2011). Studies using the landmark task have reported a similar rightward shift in bias with increased viewing distance, though not an absolute right bias at the farthest viewing distances (Bjoertomt, Cowey, & Walsh, 2002;McCourt & Garlinghouse, 2000).…”

“…Longo and Lourenco (2006) proposed that the transition in bisection bias from a left bias (i.e., pseudoneglect) in near space to a right bias in far space could result from the combination of an overall rightward attentional bias combined with a right hemisphere specialization for near space. Kinsbourne (1987) reviews a number of pieces of evidence for a baseline rightward bias (see also Làdavas, Del Pesce, & Provinciali, 1989).…”

“…Thus, on Longo and Lourenco's (2006) interpretation, pseudoneglect reflects the sum of two distinct spatial attentional biases: (1) a baseline rightward bias (Kinsbourne, 1987;Làdavas et al, 1989), and (2) a leftward bias caused by activation of near space representations in the right hemisphere. There is less evidence, however, for a right hemisphere specialization of near space.…”

“…Nevertheless, despite these difficulties, two studies by colleagues (2000, 2003) used PET (which is somewhat less spatially restrictive than MRI) to investigate bisection in near and far space, reporting largely left-lateralised activations for near, compared to far, space, opposite to the pattern predicted by Longo & Lourenco (2006).…”

“…We could therefore investigate how the effects of spatial attention reported by Foxe and colleagues change as a function of viewing distance. If representations of near space are right-lateralized (Longo & Lourenco, 2006), then the differences between the landmark and control task should decrease as viewing distance increases.…”