Cerebral asymmetries in the level of attention required for word recognition

Words presented to the right visual field (RVF) are recognised more readily than those presented to the left visual field (LVF). This RVF advantage could reflect: (a) the direct connection between the RVF and left hemisphere, (b) an attentional bias directed towards the RVF, or (c) an attentional advantage, where the left hemisphere is able to recognise words using less attention than the right hemisphere. The attentional bias and advantage models were tested in 20 dextral adults during a divided visual field word-naming task. Spatial attention was manipulated with valid, invalid, or neutral central cues. Error and reaction time measures revealed a RVF advantage for word recognition. If the attentional bias model is correct, the RVF advantage should have been attenuated for valid and invalid cues compared to neutral cues. Instead of this, an interaction emerged whereby the cueing effect was stronger for words in the LVF than the RVF. This interaction has been reported previously in studies using peripheral spatial cues. The interaction suggests that the RVF requires less attention to process words than the LVF. This left hemisphere attentional advantage may reflect asymmetries between the hemispheres in their word processing styles.