Salience in a social landscape: electrophysiological effects of task-irrelevant and infrequent vocal change

Abstract

In a dynamically changing social environment, humans have to face the challenge of prioritizing stimuli that compete for attention. In the context of social communication, the voice is the most important sound category. However, the existing studies do not directly address whether and how the salience of an unexpected vocal change in an auditory sequence influences the orientation of attention. In this study, frequent tones were interspersed with task-relevant infrequent tones and task-irrelevant infrequent vocal sounds (neutral, happy and angry vocalizations). Eighteen healthy college students were asked to count infrequent tones. A combined event-related potential (ERP) and EEG time-frequency approach was used, with the focus on the P3 component and on the early auditory evoked gamma band response, respectively. A spatial-temporal principal component analysis was used to disentangle potentially overlapping ERP components. Although no condition differences were observed in the 210-310 ms window, larger positive responses were observed for emotional than neutral vocalizations in the 310-410 ms window. Furthermore, the phase synchronization of the early auditory evoked gamma oscillation was enhanced for happy vocalizations. These findings support the idea that the brain prioritizes the processing of emotional stimuli, by devoting more attentional resources to salient social signals even when they are not task-relevant.

Where Sounds Occur Matters: Context Effects Influence Processing of Salient Vocalisations

“…The finding that a less familiar outdoor environment elicited greater cognitive response is in line with the available literature which suggests that uncertain contextual settings demand greater recruitment of processing resources [29,36]. From an evolutionary standpoint, the human's capacity to formulate consistencies and rapidly extricate irregularities from our surroundings is essential to our survival.…”

“…Several studies have ascertained that emotional recognition of vocalisations demands attentional [40] and prediction resources [37]. Furthermore, human vocalisations which are salient and convey the emotional state of another person are automatically prioritised when pitted against other competing stimuli for selective attention [15,16,36,39,41]. Therefore, integrating salient vocalisations with the ambiguous and unfamiliar OE contextual scenes could have demanded greater recruitment of the rostrolateral PFC so as to make meaning of both the auditory and visual stimuli.…”

Automaticity in the recognition of nonverbal emotional vocalizations.

“…Emotions were categorized as quickly when controlled resources were taxed by a competing task, as when the task was performed under full attention, i.e., latencies did not suffer under cognitive load, both when the load was low and when it was high. Taken together, these findings add to previous ERP research in important ways (Liu et al, 2012; Pinheiro et al, 2015; Sauter & Eimer, 2010), demonstrating that the automaticity of emotion decoding in nonverbal vocalizations can be seen at different stages of processing: in the early (unintentional) neural differentiation of emotional sounds vs. neutral ones, and in the later high-order processes involving the conscious access to the specific emotional meaning of vocalizations. An important consideration is whether the high accuracy rates that we obtained, and the small effects of cognitive load and deliberation observed, truly reflect the efficiency of the mechanism, or rather a task-related bias, i.e., a tendency to use the ‘yes’ key regardless of whether the vocalization expressed or not the target emotion.…”

Top-down Effects on Empathy for Pain in Adults with Autistic Traits

“…These samples were recorded by 10 actors (five male and five female). All audio clips were edited to be 700 ms long 25 , with a mean intensity of 70 dB 34 .…”