Was That a Scream? Listener Agreement and Major Distinguishing Acoustic Features

Abstract

Human screams have been suggested to comprise a salient and readily identified call type, yet few studies have explored the degree to which people agree on what constitutes a scream, and the defining acoustic structure of screams has not been fully determined. In this study, participants listened to 75 human vocal sounds, representing both a broad acoustical range and array of emotional contexts, and classified each as to whether it was a scream or not. Participants showed substantial agreement on which sounds were considered screams, consistent with the idea of screams as a basic call type. Agreement on classifications was related to participant gender, emotion processing accuracy, and empathy. To characterize the acoustic structure of screams, we measured the stimuli on 27 acoustic parameters. Principal components analysis and generalized linear mixed modeling indicated that classification as a scream was positively correlated with 3 acoustic dimensions: one corresponding to high pitch and roughness, another corresponding to wide fundamental frequency variability and narrow interquartile range bandwidth, and a third positively correlated with peak frequency slope. Twenty-six stimuli were agreed upon by > 90% of participants to be screams, but these were not acoustically homogeneous, and others evoked mixed responses. These results suggest that while screams might represent a salient and possibly innate call type, they also exhibit perceptual and acoustic gradation, perhaps reflecting the wide range of emotions and contexts in which they occur.

Neurocognitive processing efficiency for non-alarm rather than alarm signaling in human scream calls

“…a harsh, thrilling, croaky sound) in the broad 30-150Hz range that contributes to the alarming quality of fear screams [19]. Other studies confirmed that roughness, amongst other important acoustic and perpetual features, is a defining perceptual feature of screams that enable listeners to classify vocalizations as screams [3].…”

“…The recordings of the neutral and the 6 generic scream types resulted in a total of 420 acted scream calls that are acoustically similar to natural screams [1,2]. The screaming quality of these vocalizations was verified by ear by trained senior members of the research team, since clear formal acoustic criteria for scream calls are not yet established [3]. Scream calls are also easily identified and discriminated from other nonverbal affective vocalizations [21].…”

“…A specific type of affect burst is a scream call. Screams are relatively short, loud and intense, high-pitched, tremulous, and rough voice calls [1][2][3]. They have a far-reaching impact [1,4] and seem to be immediately recognized by, adaptively and rapidly responded to, and hardly ignored by perceivers [5,6].…”

“…a harsh, thrilling, croaky sound) in the broad 30-150Hz range that contributes to the alarming quality of fear screams [19]. Other studies confirmed that roughness, amongst other important acoustic and perpetual features, is a defining perceptual feature of screams that enable listeners to classify vocalizations as screams [3].Although previous studies thus provided a detailed functional and neural description of scream call recognition, they were limited from three perspectives. The first limitation concerns the variety of primate screams, especially human screams.…”

“…However, humans scream not only when they are fearful and aggressive, but also when they experience other affective states, similar to a variety of emotions that are more commonly expressed in less intense nonverbal vocal emotions [20], such as sadness, joy, and sensual pleasure. Second, although some previous studies seemed to have investigated a broader variety of scream-like vocalizations, these vocalizations seemed intermingled with other non-scream-like vocalizations [21] or partly collected from mixed sources [3,21]. The third limitation concerns the neural mechanisms and dynamics of scream perception, as only a limited description of neural mechanisms for scream perception is as yet available [1].…”