How Reliably Do Eye Parameters Indicate Internal Versus External Attentional Focus?

Eye behavior is increasingly used as an indicator of internal versus external focus attention both in research and application. However, available findings are partly inconsistent, which might be attributed to the different nature employed types cognition tasks. The present study, therefore, investigated how consistently eye parameters respond attentional across three task modalities: numerical, verbal, visuo-spatial. Three robustly differentiated between all Blinks, pupil diameter variance, fixation disparity variance were increased during internally directed attention. We also observed substantial effects on other (pupil diameter, disparity, saccades, microsaccades), but they moderated by type. Single-trial analysis our data using machine learning techniques further confirmed results: Classifying means tracking works well participants, generalizing tasks proves challenging. Based type parameters, we discuss what best suited indicators settings.