Affective and cognitive consequences of temporal and textural aspects of background music: a pupillometry study

Affective, physiological and cognitive consequences of musical sound are well documented, however they have rarely been studied simultaneously, and no such study employed pupillometry. In this experiment, subjective and pupillary indices of arousal were monitored while participants carried out a colour-word Stroop test with concurrently presented musical excerpts varying in tempo and degree of percussiveness. It was investigated whether increases in tempo are associated with greater self-reported arousal as well as greater tonic pupillary responses and if effects of tempo on both indices of arousal are moderated by the degree of percussiveness of the musical excerpt. It was also assessed whether background music affects performance on the colour-word Stroop test and to what extent these effects are mediated by self-reported and autonomic arousal. Additionally, pupillary responses were investigated in terms of responses to Stroop stimuli during exposure to music in order to clarify the relative influences of arousal and cognitive load on pupillary responses. 32 participants took part in this within-subjects experiment, which assessed subjective and pupillary indices of arousal to musical excerpts varying in degree of percussiveness, and which were edited to produce three versions of each musical piece that varied in tempo (slow, moderate and fast). Participants completed a manual response colour-word Stroop task in silence and during exposure to each of the nine musical stimuli while an infra-red remote eye-tracker monitored changes in pupillary diameter. Reaction times to congruent and incongruent Stroop stimuli were recorded. Both pupillary and subjective measures were found to be influenced by tempo although tempo influenced subjectively reported arousal to a much greater extent. Some evidence for the moderating role of percussiveness was also found. However, there were no cognitive consequences observable in the Stroop test latencies. Pupillary Stroop effect failed to replicate and due to this very limited inferences concerning priority of cognitive load over arousal in pupillary responses can be drawn. Despite a great body of research suggesting that background music has cognitive consequences mediated by musically-induced arousal, findings of the present experiment indicate that subjective and physiological arousal is not inevitably reflected in cognitive processing