Offset masking in a divided visual field study.

A problem in divided visual field studies (especially those using event-related potentials as a dependent measure) is the large number of horizontal eye movements participants make during experimental trials. Past attention research suggests that eye movements to lateralised targets should be significantly reduced using a dynamic, offset mask, causing a reduction in attentional capture. The current study attempted to replicate past divided visual field language studies using offset masking procedures. Using a basic offset procedure, eye movements were not reduced in Experiment 1. However, Experiment 2 did show a significant reduction in eye movements using a new dynamic offset masking procedure. Low accuracy rates were a concern throughout. In conclusion, horizontal eye movements can be reduced with a dynamic offset procedure but the low accuracy rates and the inconsistent behavioural findings throughout the study suggest that further study and refinement of the paradigm is needed.