The well-known “cocktail party effect” refers to incidental detection of salient words, such as one's own name, in supposedly-unattended speech. However, empirical investigation of the prevalence of this phenomenon and the underlying mechanisms has been limited to extremely artificial contexts and has yielded conflicting results. We introduce a novel empirical approach for revisiting this effect under highly ecological conditions, by immersing participants in a multisensory virtual café and using realistic stimuli and tasks. Participants (32 female, 18 male) listened to conversational speech from a character at their table, while a barista in the back of the café called out food orders. Unbeknownst to them, the barista sometimes called orders containing either their own-name or words that created semantic violations. We assessed the neurophysiological response-profile to these two probes in the task-irrelevant barista-stream by measuring participants’ brain activity (EEG), galvanic skin response (GSR) and overt gaze-shifts.We found distinct neural and physiological responses to participants’ own-name and semantic violations, indicating their incidental semantic processing despite being task-irrelevant. Interestingly, these responses were covert in nature and gaze-patterns were not associated with word-detection responses. This study emphasizes the non-exclusive nature of attention in multimodal ecological environments and demonstrates the brain’s capacity to extract linguistic information from additional sources outside the primary focus of attention.Significance StatementWe address one of the most well-known, yet puzzling, aspects of human cognition - how do we focus our attention in noisy environments, and to what extent are words from seemingly ‘unattended’ sources incidentally processed by the brain.We measured neural activity, eye-movements and physiological responses from humans in a Virtual Café, and monitored whether their brain picks up information from background speech, eventhough it is not behaviorally relevant to them.We found distinct neural and physiological responses to hearing ones' name and to implausible sentences in background speech, demonstrating their processing at a semantic level, despite being irrelevant.These results promote a non-exclusive perspective of real-life attention whereby multiple stimuli are co-represented, rather than a narrow spotlight of selective attention.

We acknowledge and pay respect to the people of the Yugambeh Nation on whose Land we work, meet and study. We recognise the significant role the past and future Elders play in the life of the University and the region. We are mindful that within and without the buildings, the Land always was and always will be Aboriginal Land.1This paper introduces staying-with the traces of inter/intra-subjective experience, with and within place, in mapping-making philosophy in environmental education. Through a conceptualisation of philosophy as concepts or knots in an infinite composition of knowledge, rather than separate knowledges, we use staying-with the traces2 as method, whereby our embodied patterns of human and more than human relationality across place and time may engage with philosophy. This grounding of philosophy foregrounds the diverse onto-epistemologies of posthumanism and indigenist3 ways of knowing, acknowledging tensions and searching for the possibilities of connectivity between them. Through an embodied arts-based walking practice, our approach challenges the perpetuation of reductionist perspectives, including nature/culture binaries, within environmental education. We stay with the traces of bird, meeting, tree, watery and concrete in mutual inseparable relation and becoming.

Many situations require focusing attention on one speaker, while monitoring the environment for potentially important information. Some have proposed that dividing attention among two speakers involves behavioral tradeoffs, due to limited cognitive resources. However the severity of these tradeoffs, particularly under ecologically-valid circumstances, is not well understood. We investigated the capacity to process simultaneous speech using a dual-task paradigm simulating task demands and stimuli encountered in real-life. Participants listened to conversational narratives (Narrative Stream) and monitored a stream of announcements (Barista Stream), to detect when their order was called. We measured participants' performance, neural activity and skin conductance as they engaged in this dual-task. Participants achieved extremely high dual-task accuracy, with no apparent behavioral tradeoffs. Moreover, robust neural and physiological responses were observed for target-stimuli in the Barista Stream, alongside significant neural speech-tracking of the Narrative Stream. These results suggest that humans have substantial capacity to process simultaneous speech and do not suffer from insufficient processing resources, at least for this highly ecological task-combination and level of perceptual load. Results also confirmed the ecological validity of the advantage for detecting ones' own name at the behavioral, neural and physiological level, highlighting the contribution of personal relevance when processing simultaneous speech.

Many situations require focusing attention on one speaker, while monitoring the environment for potentially important information. Some have proposed that dividing attention among 2 speakers involves behavioral trade-offs, due to limited cognitive resources. However the severity of these trade-offs, particularly under ecologically-valid circumstances, is not well understood. We investigated the capacity to process simultaneous speech using a dual-task paradigm simulating task-demands and stimuli encountered in real-life. Participants listened to conversational narratives (Narrative Stream) and monitored a stream of announcements (Barista Stream), to detect when their order was called. We measured participants’ performance, neural activity, and skin conductance as they engaged in this dual-task. Participants achieved extremely high dual-task accuracy, with no apparent behavioral trade-offs. Moreover, robust neural and physiological responses were observed for target-stimuli in the Barista Stream, alongside significant neural speech-tracking of the Narrative Stream. These results suggest that humans have substantial capacity to process simultaneous speech and do not suffer from insufficient processing resources, at least for this highly ecological task-combination and level of perceptual load. Results also confirmed the ecological validity of the advantage for detecting ones’ own name at the behavioral, neural, and physiological level, highlighting the contribution of personal relevance when processing simultaneous speech.

Detecting that someone has said your name is one of the most famous examples for incidental processing of supposedly-unattended speech. However, empirical investigation of this so-called "cocktail party effect" has yielded conflicting results. We present a novel empirical approach for revisiting this effect under highly ecological conditions, by immersing participants in a multisensory virtual cafe environment and using realistic stimuli and tasks. Participants listened to conversational speech from a character sitting across from them, while a barista in the back of the cafe called out food orders. Unbeknownst to them, the barista sometimes called orders containing their own name or semantic violations. We used combined measurements of brain activity (EEG), eye-gaze and galvanic skin response to assess the response-profile to these two probes in the task-irrelevant barista-stream. Both probes elicited unique neural and physiological responses relative to control stimuli, indicating that the system indeed processed these words and detected their unique status, despite being task-irrelevant. Interestingly, these responses were covert in nature and were not accompanied by gaze-shifts towards the barista character. This pattern demonstrates that under these highly ecological conditions, listeners incidentally pick up information from task-irrelevant speech, emphasizing the dynamic and non-binary nature of attention in real-life environments.