On the generalization of tones: A detailed exploration of non-speech auditory perception stimuli

Michael Schutz,Jessica Gillard

doi:10.1038/s41598-020-63132-2

Abstract

The dynamic changes in natural sounds’ temporal structures convey important event-relevant information. However, prominent researchers have previously expressed concern that non-speech auditory perception research disproportionately uses simplistic stimuli lacking the temporal variation found in natural sounds. A growing body of work now demonstrates that some conclusions and models derived from experiments using simplistic tones fail to generalize, raising important questions about the types of stimuli used to assess the auditory system. To explore the issue empirically, we conducted a novel, large-scale survey of non-speech auditory perception research from four prominent journals. A detailed analysis of 1017 experiments from 443 articles reveals that 89% of stimuli employ amplitude envelopes lacking the dynamic variations characteristic of non-speech sounds heard outside the laboratory. Given differences in task outcomes and even the underlying perceptual strategies evoked by dynamic vs. invariant amplitude envelopes, this raises important questions of broad relevance to psychologists and neuroscientists alike. This lack of exploration of a property increasingly recognized as playing a crucial role in perception suggests future research using stimuli with time-varying amplitude envelopes holds significant potential for furthering our understanding of the auditory system’s basic processing capabilities.

Highlights

When designing research studies, scientists strive to minimize confounds potentially confusing experimental outcomes
Later when expanding the survey to include the auditory-focused Hearing Research (HR) we turned to Web of Science, as HR is not indexed by PsycInfo
Our analysis illustrates a surprising lack of attention to the reporting of amplitude envelope, with 37.6% of stimuli from 1017 experiments omitting any information about their temporal structure (Fig. 3)

Summary

Introduction

Scientists strive to minimize confounds potentially confusing experimental outcomes. Researchers take great pains to avoid confounding factors through carefully designed paradigms employing tightly controlled stimuli This approach has undoubtedly contributed to psychology’s success in explaining many complex phenomena, overuse of simplified tones in experiments can lead to inaccurate perspectives on perceptual processing. With the invention of the vacuum tube and modern computers, many researchers eagerly traded natural sounds for precisely controlled tones[10] Concern with this decision is hardly novel, as colleagues have previously expressed worry that much of auditory psychophysics “lack[s] any semblance of ecological validity”[10] given the dearth of amplitude invariant Many experiments are conducted with a single type of amplitude envelope—the temporally simplistic flat tone Their artificial characteristics embody the concern clearly articulated by Gaver[4,5] and others[10] warning of a divide between the auditory system’s use in everyday listening and its assessment in the laboratory. The following series of experiments on audio-visual integration illustrates one specific example of problems endemic with over-using a single type of stimulus to pursue a generalized understanding of psychological processes

Methods

Results

Conclusion