Brian Gygi

Purpose: Previously, Gygi and Shafiro (2011) found that when environmental sounds are semantically incongruent with the background scene (e.g., horse galloping in a restaurant), they can be identified more accurately by young normal-hearing listeners (YNH) than sounds congruent with the scene (e.g., horse galloping at a racetrack). This study investigated how age and high-frequency audibility affect this Incongruency Advantage (IA) effect. Method: In Experiments 1a and 1b, elderly listeners ( N = 18 for 1a; N = 10 for 1b) with age-appropriate hearing (EAH) were tested on target sounds and auditory scenes in 5 sound-to-scene ratios (So/Sc) between −3 and −18 dB. Experiment 2 tested 11 YNH on the same sound–scene pairings lowpass-filtered at 4 kHz (YNH-4k). Results: The EAH and YNH-4k groups exhibited an almost identical pattern of significant IA effects, but both were at approximately 3.9 dB higher So/Sc than the previously tested YNH listeners. However, the psychometric functions revealed a shallower slope for EAH listeners compared with YNH listeners for the congruent stimuli only, suggesting a greater difficulty for the EAH listeners in attending to sounds expected to occur in a scene. Conclusions: These findings indicate that semantic relationships between environmental sounds in soundscapes are mediated by both audibility and cognitive factors and suggest a method for dissociating these factors.

The effect of context on the identification of common environmental sounds (e.g., dogs barking or cars honking) was tested by embedding them in familiar auditory background scenes (street ambience, restaurants). Initial results with subjects trained on both the scenes and the sounds to be identified showed a significant advantage of about five percentage points better accuracy for sounds that were contextually incongruous with the background scene (e.g., a rooster crowing in a hospital). Further studies with naive (untrained) listeners showed that this incongruency advantage (IA) is level-dependent: there is no advantage for incongruent sounds lower than a Sound/Scene ratio (So/Sc) of -7.5 dB, but there is about five percentage points better accuracy for sounds with greater So/Sc. Testing a new group of trained listeners on a larger corpus of sounds and scenes showed that the effect is robust and not confined to a specific stimulus set. Modeling using spectral-temporal measures showed that neither analyses based on acoustic features, nor semantic assessments of sound-scene congruency can account for this difference, indicating the IA is a complex effect, possibly arising from the sensitivity of the auditory system to new and unexpected events, under particular listening conditions.

Loebach and Pisoni [J. Acoust. Soc. Am. 123, 1126–1139 (2008)] demonstrated perceptual improvements following a brief training with spectrally degraded environmental sounds generalized to speech. The present study investigated whether benefit could also result from mere exposure over a longer time period. Participants received two pretests, one week apart, prior to beginning a week‐long environmental sound training regimen, which was followed by two post‐test sessions, separated by another week without training. Spectrally degraded stimuli, processed with a four‐channel vocoder, consisted of a 160‐item environmental sound test, word and sentence tests (CNC, SPIN), and a battery of psychoacoustic and cognitive tests. Results indicated significant improvements in all speech and environmental sound scores between the initial pretest and the last post‐test, with performance increments following both exposure and training. For environmental sounds (the stimulus class that was trained), the magnitude of positive change that accompanied training was much greater than that due to exposure alone, with improvement for untrained categories roughly comparable to the speech benefit from exposure. Speech and environmental sound performance were differentially correlated with tests of spectral and temporal‐fine‐structure processing abilities, while working memory and executive function were correlated with speech, but not environmental sound perception. [Work supported by NIH.]

Limited research has investigated cochlear implant (CI) patients' ability to perceive environmental sounds. In this study, environmental soundperception was assessed with a large‐item test composed of 40 sound sources, each represented by four different tokens. The relationship between speech and environmental soundperception and the role of working memory and basic auditory abilities was examined based on patient performance on a battery of speech tests (HINT, CNC, and individual consonant and vowel tests), tests of basic auditory abilities (audiometric thresholds, gap detection, temporal pattern and temporal order tests), and a backward digit recall test. Twelve postlingually deaf adult CI patients, having 1‐5 years of implant experience participated. The results indicate substantially reduced ability to identify common environmental sounds in CI patients. Speech test scores correlated strongly with the scores on the environmental sound test. Both speech and environmental sound tests moderately correlated with gap detection, temporal order test and backward digit recall test. However, the correlation between speech and environmental sounds changed little after partialling out the variance due to other variables. These results suggest that speech and environmental sounds may overlap considerably in their perceptual processing, being largely independent of peripheral limitations that may affect both sound classes.

Four experiments investigated the acoustical correlates of similarity and categorization judgments of environmental sounds. In Experiment 1, similarity ratings were obtained from pairwise comparisons...

Environmental sound research is still in its beginning stages, although in recent years there has started to accumulate a body of research, both on the perception of environmental sounds themselves, and on their practical applications in other areas of auditory research and cognitive science. In this chapter some of those practical applications are detailed, combined with a discussion of the implications of environmental sound research for auditory perception in general, and finally some outstanding issues and possible directions for future research are outlined.