Abstract
Pseudoneglect is the presence of a left-ward asymmetry in spatial cognition in neurotypical individuals (Bowers & Heilman, Neuropsychologia, 18(4):491, 1980). This effect is commonly demonstrated using bisection tasks that show participants are more likely to perceive the left-side of a line as longer than in reality (Jewell & McCourt, 2000). Current theories suggest that pseudo-neglect is a consequence of hemispheric lateralisation in spatial attention (Bowers & Heilman, 1980), this assumes that the bias should remain consistent across both time and modality. However, the reliability of pseudone-glect is poorly researched, with only a few studies investigating reliability across time (Learmonth et al., PLOSone, 10(9), 2015; Nicholls, Bradshaw, & Mattingley, Neuropsychologia, 37(3):307, 1999). Here we investigate whether biases in pseudoneglect are consistent across both time and modality. We used three different tasks; visuomotor manual line bisection (MLB), visual landmarks bisection and tactile rod bisection (TRB). These tasks were tested over four separate sessions. Cronbach’s alpha was used to assess reliability of participants’ responses for both hypotheses. Biases in line bisection for both the visual landmarks (alpha = 0.78, p < .001) and TRB tasks (alpha = 0.57, p = .009) were found to be reliable across sessions. This was not the case for MLB (alpha = 0.01 p = .459). We also found poor reliability between tasks (alpha = 0.27, p = 0.261) suggesting that biases in spatial attention are not consistent across modalities. This result challenges the theory that hemispheric lateralisation causes pseudoneglect and, importantly, questions whether the right-hemisphere dominance hypothesis can also explain disorders of lateralised attention, such as spatial neglect.