Eye guidance and visual search

This chapter presents an account of eye control during visual search. The primary mechanism for selection of the destination for each saccade involves the generation of an oculomotor salience map, in which processes of biased competition boost the salience signal at locations containing visual material that is similar to the search target. Generation of the salience map is a dynamic process. This is most clearly seen in the statistical properties of saccades in a task. Individual saccades appear generally to be ballistic, with the end point determined in advance, although the trajectory can reflect the dynamic activity. Additional forward planning mechanisms that allow saccade destinations to be 'pipelined' in some circumstances supplement the salience map. Further processes involving visual memory, such as inhibition of return, operate to allow saccades to be distributed over different regions of the search area.