Pupillometric indices of temporal order representation in semantic memory

Abstract

Summary. The present study used the technique of pupillometry to study whether pupillary changes are sensitive to variations in the processing of temporal order information in semantic memory. By employing two recognition tasks the temporal orientation (chronological vs. reverse) between pre-information and target was manipulated. The first experiment examined frequently occurring sequences of everyday events (e.g., cut - bleed - bandage) with the same strength of temporal relatedness for preceding and succeeding events. The second experiment investigated event-feature pairs (e.g., melt, solid - fluid) with temporal connectives (before, after). In addition to the psychological indicators reaction times and error rates two further psychophysiological indicators - maximum pupil diameters and dilatation times - were raised to validate the behavioral data. The results show that time’s arrow is not restricted to sequences of events, but also embedded in the mental representation of individual events. In both experiments psychophysiological indicators coincide with the psychological indicators. The pupillometric results provide additional new information: They indicate that the processing of temporal orientation towards future time does not only consume less time and produces less errors, but also that the processing is making less demands on mental resources. The presented study demonstrates that task-evoked pupillary response is a reliable and sensitive indicator for the experimental study of cognitive load.