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Newman, Aaron

Permanent URI for this collectionhttps://hdl.handle.net/10222/27784

Aaron Newman

Associate Professor

Email: Aaron.Newman@dal.ca

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Now showing 1 - 5 of 5
  • ItemOpen Access
    Context Matters: Hyperscanning the N400 Lexical Frequency Effect During Conversation and Passive Listening
    (2025-03-23) Douglas, Caitriona L.; Tremblay, Antoine; Newman, Aaron J.
    Conventional event-related potential (ERP) studies of lexical processing typically involve individuals comprehending isolated words or sentences. However, much of language processing occurs in conversation with others. Here, we used EEG hyperscanning to record ERPs from pairs of acquaintances either engaged in conversation, or passively viewing a conversation. Our primary goals were to replicate the established N400 frequency effect (a greater amplitude negativity between ~300–600 ms for low-frequency words), and compare this effect during conversation versus passive viewing, which more closely resembles traditional ERP paradigms. Pairs of participants engaged in a scripted conversation while EEG was simultaneously recorded from both interlocutors. Separately, pairs of individuals watched a recording of the same scripted conversation to control for the effect of social interaction. Target words of high and low lexical frequency were embedded in the dialogues, and the onsets of these words were identified post hoc from audio synchronized with the EEG data. Both groups exhibited a significantly greater N400 response to low-frequency words compared to high-frequency words, replicating previous findings. However, the N400 frequency effect was larger in the passive viewing group than in the conversation group across midline central-parietal channels. This attenuation in the conversation condition may reflect differences in lexical processing during active social interaction compared to passive comprehension. These findings demonstrate that ERP experiments can be conducted using natural conversational stimuli, opening new opportunities to study real-time language processing in interactive social contexts.
  • ItemOpen Access
    Ortho-semantic learning of novel words: An event-related potential study of grade 3 children
    (Frontiers Media S.A., 2024) Galilee, Alena; Beck, Lisa J.; Lownie, Clara J.; Veinot, Jennika; Mimeau, Catherine; Dempster, Tammy; Elliott, Laura M.; Deacon, S. Hélène; Newman, Aaron J.
    Introduction: As children become independent readers, they regularly encounter new words whose meanings they must infer from context, and whose spellings must be learned for future recognition. The self-teaching hypothesis proposes orthographic learning skills are critical in the transition to fluent reading, while the lexical quality hypothesis further emphasizes the importance of semantics. Event-related potential (ERP) studies of reading development have focused on effects related to the N170 component — print tuning (letters vs. symbols) and lexical tuning (real words vs. consonant strings) — as well as the N400 reflecting semantic processing, but have not investigated the relationship of these components to word learning during independent reading. Methods: In this study, children in grade 3 independently read short stories that introduced novel words, then completed a lexical decision task from which ERPs were derived. Results: Like real words, newly-learned novel words evoked a lexical tuning effect, indicating rapid establishment of orthographic representations. Both real and novel words elicited significantly smaller N400s than pseudowords, suggesting that semantic representations of the novel words were established. Further, N170 print tuning predicted accuracy on identifying the spellings of the novel words, while the N400 effect for novel words was associated with reading comprehension. Discussion: Exposure to novel words during self-directed reading rapidly establishes neural markers of orthographic and semantic processing. Furthermore, the ability to rapidly filter letter strings from symbols is predictive of orthographic learning, while rapid establishment of semantic representations of novel words is associated with stronger reading comprehension.
  • ItemOpen Access
    Towards Mind Wandering Adaptive Online Learning and Virtual Work Experiences
    (2022-06-14) Conrad, Colin; Newman, Aaron J.
    NeuroIS researchers have become increasingly interested in the design of new types of information systems that leverage neurophysiological data. In this paper we describe the results of machine learning analysis which validates a method for the passive detection of mind wandering. Following the presentation of the results, we describe ways that this technique could be applied to create a neuroadaptive online learning and virtual meeting tool which may improve users' retention of information by providing auditory feedback.
  • ItemOpen Access
    Age of Onset and Duration of Deafness Drive Brain Organization for Biological Motion Perception in Non-Signers
    (2016-09) Muise-Hennessey, Alexandria; Tremblay, Antoine; White, Nicole C.; McWhinney, Sean R.; Zaini, W. Hazlin; Maessen, Heather; Comeau-Grandy, Adrienne; Bance, Manohar; Newman, Aaron J.
    We used fMRI to characterize the neural responses to biological motion in adults who became deaf at a wide range of ages, none of whom were fluent sign language users. Although hearing people showed stronger activation for communicative than non-communicative gestures throughout the occipito-temporal biological motion and frontal-parietal action perception networks, deaf people showed equivalent levels of activation to both types of stimuli, suggesting an enhanced sensitivity to biological motion. Deaf people exclusively showed responses to communicative gestures in the left superior temporal gyrus (associated with speech processing) and right inferior parietal lobe. Further, earlier onset and longer duration of deafness led to stronger cortical responses in the biological motion and action perception networks, and extended into left superior temporal lobe areas associated with speech and other auditory processing. Together these results demonstrate that auditory deprivation, in the absence of sign language experience, can profoundly change the sensitivity of cortical networks for communicative biological motion processing. Furthermore, we demonstrate for the first time that neuroplastic reorganization of the visual system can occur even in people who became deaf after childhood.
  • ItemOpen Access
    Sensitivity to White Matter fMRI Activation Increases with Field Strength
    (2013-03) Mazerolle, Erin L.; Gawryluk, Jodie R.; Dillen, Kim N. H.; Patterson, Steven A.; Feindel, Kirk W.; Beyea, Steven D.; Stevens, M. Tynan R.; Newman, Aaron J.; Schmidt, Matthias H.; D'Arcy, Ryan C. N.
    No abstract available.