Pupil Diameter Does Not Correlate with Fixation Duration - or Does It?

A number of pupillometric studies have suggested that dynamic differences in pupil diameter correlate with dierent levels of cognitive intensity or excitement. Other studies have suggested a similar correlation between fixation duration and cognitive effort. Since both methodologies for hypothesizing about cognitive effort are contested, we examined if the two measures co-vary in eye-tracked observations of translators while performing a translation or text-revision task.
A plot representation of pupil diameter measurements inserted in a progression graph showing a participant's gaze path while translating/revising indicated that diameter size pulsates regularly throughout such tasks, with peaks occurring task initially, before final revision, and, occasionally, during the drafting phase, typically at intervals with no typing activity. From the point of view of validating the two microbehavioural methodologies, the most interesting result was establishing whether or not the pupil diameter of translators and revisers co-varies systematically with fixation duration, such that the occurrence of larger-than-average pupil diameters correlates with longer-than-average fixations, regardless of what linguistic material they
are fixations of.
We tested the assumption on six recordings of translation sessions in three different experiments, all of which are available in the CBS database of translation and postediting process recordings.