Acoustics/Sound

McFarlane and colleagues have investigated, via an online survey, the sorts of sounds that alarms to wake people up can make and the repercussions of awakening to various sounds. Their findings are generally relevant to people working on creating sounds that alert listeners.  The McFarlane-lead team reports that “Sleep inertia is a potentially dangerous reduction in human alertness and occurs 0–4 hours after waking. . . .  The goal of this research is to understand how a particular sound or music chosen to assist waking may counteract sleep inertia. . .

Astolfi and colleagues investigated the effects of classroom acoustics on the educational experiences of young people, age 6 to 7.  They determined that “findings of the study suggest that long reverberation times, which are associated to poor classroom acoustics as they generate higher noise levels and degraded speech intelligibility, bring pupils to a reduced perception of having fun and being happy with themselves.

Arnal and teammates probed what sorts of sounds alarm humans.  They found that “One strategy, exploited by alarm signals, consists in emitting fast but perceptible amplitude modulations in the roughness range (30–150 Hz). . . . Rough sounds synchronise activity throughout superior temporal regions, subcortical and cortical limbic areas, and the frontal cortex, a network classically involved in aversion processing.”  Rough sounds from 40-80 Hz are especially unpleasant for us to hear.  The 40-80 Hz range is where the frequencies of babies crying, human screams, and many alarms are found.

Researchers from the Universidad Carlos III de Madrid, the University of Sussex, and University College London investigated how scents and sounds influence our perceptions of our bodies. The team found “that olfactory stimuli combined with auditory stimuli can change our perception of our body. . . . People feel thinner and lighter when exposed to the smell of lemon, while feeling heavier and more corpulent when they smell vanilla. . . . Through a device adapted to a pair of shoes . . . .