Right hemisphere superiority for subitising

Abstract

Lateral differences in the enumeration of small sets of items (i.e., between two and five) were investigated in a normal adult sample. Confounds due to stimulus repetition, which have characterised previous subitising research, were eliminated in a task involving the presentation of purely random item arrays to the left and right visual fields. The results indicated a clear left visual field advantage for the enumeration of arrays containing three to four items. This finding is consistent with the widely held view that the subitising process is used to enumerate arrays of up to four items, and calls into question Butterworth's (1999) recent claim that subitising is a left hemisphere process. The implications for previous pattern recognition and visual process accounts of this ability are considered.

What impairs subitizing in cerebral palsied children?

“…In contrast, it appears from our results that a right lesion increases the risk of disruption of the subitizing process, more so on canonical than on random arrangement, possibly because of the gestalt perception involved in the former. This finding supports the idea of right-hemisphere involvement in subitizing (Jackson & Coney, 2004;Pasini & Tessari, 2001). It also is interesting to relate our results to the visuospatial impairment observed in syndromes such as Williams syndrome, spatial agnosia, or ''white fiber connection.''…”

“…Since the right hemisphere has been shown to be involved in subitizing (Jackson & Coney, 2004), we hypothesized that different types of lesions should be reflected in the subitizing task results.…”

“…We also checked the available files of the CP children to see whether their results could be related to lesion location. Since the right hemisphere has been shown to be involved in subitizing (Jackson & Coney, 2004), we hypothesized that different types of lesions should be reflected in the subitizing task results.…”

Bilateral Field Advantage in Visual Enumeration

“…To further explore this effect, we carried out separate analyses for each of the four vertical positions (i.e., far left, near left, near right, and far right) and the results showed a vertical advantage only when the dots were displayed in the far left quadrants, t(16) = −8.66, p<.001 (see Figure 4c). This finding suggests that the vertical advantage observed in this experiment may simply reflect a left hemifield bias in enumeration [19]–[21]. Finally, the 2 (condition) ×7 (numerosity) ANOVA (repeated measures) on CVs revealed no effect of condition (p>.05), a main effect of numerosity, F(3.20, 51.27) = 51.72, MSE = 0.001, p<.001, and no significant condition × numerosity interaction (p>.54).…”

“…Previous investigations on visual field asymmetries for enumeration processes have provided controversial results. Some studies have revealed a left visual field advantage for enumeration [19]–[21], whereas other neuroimaging [22], [23] and neuropsychological [24] studies have found equivalent enumeration performance in both hemifields. More research is needed to clarify this issue and this will not be further discussed.…”