Speeded detection of sound signals based on temporal differences
Résumé
Previous research has identified acoustic parameters modulating the perceived urgency of alarms. Such approaches have focused mainly on the subjective relationship between characteristics of the alarms and the perception of urgency. We suggest that an objective measurement will ensure with more certainty the effectiveness of the acoustic parameters and will help us to understand more precisely the underlying processes. We have to improve ability of warning signals to increase the probability of a faster reaction under emergency conditions. Thus, we performed two experiments using a speeded reaction-time (RT) paradigm, under two tracking task conditions: motor and visual. Experiment 1 studied the influence of the tempo of the sequences. RT decreased as tempo became faster. Experiment 2 studied the influence of temporal irregularity. Outlier analyses show that RT decreased with the irregularity of the sequences. A scaled judgment of urgency was also given by subjects. Two underlying processes seem to be involved: experiment 1 highlights expectancy effects (temporal regularities provide a temporal reference frame), whereas experiment 2 emphasizes capture effects (a temporally perturbed event is more salient than a temporally expected one) [Mari Jones, 2004]. Moreover, comparisons between RT measurements and subjective judgements improve the validity of our approach.