Predictive strategies in eye-head co-ordination during text processing

During text processing skilled touch typists often scan copy and display in a repetitive way. They read a text string from the copy and consecutively check the typed characters on the display. This behavioural pattern permits analysis of eye-head co-ordination with respect to two different modes of visual information uptake, i.e. reading and checking. The results obtained showed that the eye-head co-ordination was predictive mainly in the sense that the head started to move a certain amount of time before the eye saccade was initiated. This effect has been analysed here in order to obtain criteria for the evaluation of cognitive difficulties during the performance of visual search tasks.