Pupillary response to auditory versus visual mental loading: a pilot study using super 8-mm photography.

The present investigation was two-fold in purpose: to test the hypothesis that auditory mental loading would require greater mental effort and larger resultant pupillary dilation than visual mental loading, and to provide evidence for the feasibility of super 8-mm photography for pupillometric research. Subjects were 30 college students. Stimuli to be stored in memory and repeated aloud in reverse order were seven-digit number-series. Series were either presented visually from 35-mm slides or auditorily from a taped recording. Pupillary responses were recorded to the nearest centimeter on a projected image. Results did not support the hypothesis, but methodologically strong evidence supported 8-mm photography for pupillometry research.