Aversive Acoustic Stimuli

Basic Philosophy: Sounds can cause emotional responses in people. This is utilized to get fans excited during sporting events or to calm people during mediation exercises. Some sounds are considered rather aversive by people, such as sound of the dentist drill, but this kind of response is usually a result of learned associations (e.g. the dentist drilling a tooth). We have questioned whether there are any sounds that are generally found to be aversive by people because of the characteristics of the sounds themselves (not requiring any learning, per se).

Assessment of Aversion: We use a 2-step process to determine sound aversiveness.

1. As sounds are developed, we have a group of people assess them using likert scales of pleasantness-unpleasantness, degree each is irritating, and degree each is unsettling. Those that attain the highest aversive ratings are then utilized in the second stage of testing.
2. The second stage of testing involves experimentation with naïve subjects. They are recruited to listen to the sounds, sometimes while doing other tasks, and we assess whether they produce an instrumental response that will terminate the sound (an escape response). We are examining which sounds elicit the most escape responses and the shortest latencies to produce those escape responses.

Applied Experimentation: The sounds that are determined to be most aversive are used in subsequent experiments that are based on different usage scenarios.

1. Crowd deterrence: Can sounds deter motivated people from approaching a desired location?
2. Crowd dispersion: Can sounds entice people to leave an area they currently occupy?