Coordination of Head and Eyes during the Performance of Natural (and Unnatural) Visual Tasks

According to Lashley, the key in achieving coordinated patterns of action was to program diverse motor responses with reference to a single, central spatial map and a single internal clock. This chapter studies the coordinated head and eye movements during natural and unusual performance of visual tasks, and the results of the investigations in scanning the unusual head-eye movement combinations. Three characteristics were revealed regarding the normal coordination of head and eye movements. The first one is that moving the head can increase saccades rate. The second is that the ability to perform unusual patterns of head and eye movements is different during a task with clear cognitive components than during less natural tasks when the observer tries to direct the eye to an eccentric target without cognitive significance. Lastly, there is a natural tendency to program head and eye movements concurrently in similar spatial and temporal patterns.