The role of orthographic neighbourhood effects in lateralized lexical decision: A replication study and meta-analysis.

Orthographic neighbourhood size (N) effects differ under lateralized presentation. Evidence suggests a facilitatory effect of N in the right hemisphere. However, the effect of N in the left hemisphere remains controversial: it may have a weaker facilitative role or it may even be inhibitory. In a pre-registered online experiment, we aimed to replicate the interaction between N and visual field and provide support for an inhibitory effect of N in the left hemisphere. We subsequently conducted a pre-registered systematic review and meta-analysis to synthesise the available evidence and determine the direction of N effects across hemispheres. Based on the evidence, it would seem the effect is inhibitory in the left hemisphere. Furthermore, the size of the N effect is considerably smaller in the left hemisphere. Both studies revealed vast heterogeneity between participants and studies, and we consider the implications of this for future work.