Structured sound and the temporal organization of vigilance behavior

Abstract

Auditory noise is often treated as a background condition or source of interference, yet noise contains measurable spectral structure that may shape attention and performance. Prior research suggests that noise can influence arousal, sustained attention, and response variability, but these effects are unlikely to be uniformly helpful or harmful. This thesis examined whether pink, white, and brown noise functioned as structured auditory contexts during a visual vigilance task. Participants completed a sustained signal-detection task in which they monitored a moving Gabor stimulus for subtle rotational changes while exposed to one auditory condition. Traditional behavioral outcomes, including hit rate, false alarm rate, response time, d′, β, and criterion c, were analyzed alongside distributional, recurrence, multifractal, and scan-path measures. Traditional Signal Detection Theory and mean response-time analyses did not show clear omnibus differences among the three sound-profile conditions. However, temporal and eye-movement analyses indicated that performance organization remained informative even when average behavioral outcomes were broadly similar. Response-time recurrence provided descriptive evidence about behavioral organization, whereas scan-path analyses provided the strongest nonlinear evidence: scan-path MFDFA supported participant-level profile interpretation, and scan-path RQA showed a condition difference in laminarity. These findings support the thesis in modified form. Pink, white, and brown noise should not be evaluated only by whether they improve or impair average performance; they may also be examined as structured contexts in which vigilance behavior unfolds over time. Future research should test longer vigilance tasks, larger samples, additional sound profiles, physiological measures, and individual-difference predictors.