Altmann, G. T.
Department of Psychology, University of York, UK
The influence of language on eye movements is, to all intents and purposes, as fast as it could possibly be. Here, we consider exactly what this must mean in terms of the processes that support eye movement control and the processes and representations that are engaged by the language comprehension system. The first set of studies explores when the earliest linguistic influences of language can be observed on the oculomotor system. We find influences as early as 100 ms at which point they most likely reflect the cancellation of already-planned saccades, due to competition between covert attention towards an endogenously cued target (i.e. to where we were going to move our eyes) and covert attention towards an exogenously cued location (i.e. to where the language then told us to instead move our eyes); cf. the double-step paradigm. The second set of studies explored such competitive influences in the context of pursuit eye movements: Verbs denoting upward or downward motion (e.g. ‘climb’/‘dive’) were presented auditorily as participants pursued a dot moving vertically or horizontally. When the directionality implied by the verb was congruent with the direction in which attention had to be deployed to track the target, eye velocity increased. When incongruent, it decreased. This interaction, between attention during pursuit and the task-irrelevant (but attentionally modulating) language, suggests a process in which language can activate representations which compete with those that regulate oculomotor control. Taken together, the data argue for a tight theoretical linkage between language comprehension, attention, and oculomotor control.