193 research outputs found

    Identification and classification of facial familiarity in directed lying: an ERP Study

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    Recognizing familiar faces is essential to social functioning, but little is known about how people identify human faces and classify them in terms of familiarity. Face identification involves discriminating familiar faces from unfamiliar faces, whereas face classification involves making an intentional decision to classify faces as 'familiar' or 'unfamiliar.' This study used a directed-lying task to explore the differentiation between identification and classification processes involved in the recognition of familiar faces. To explore this issue, the participants in this study were shown familiar and unfamiliar faces. They responded to these faces (i.e., as familiar or unfamiliar) in accordance with the instructions they were given (i.e., to lie or to tell the truth) while their EEG activity was recorded. Familiar faces (regardless of lying vs. truth) elicited significantly less negative-going N400f in the middle and right parietal and temporal regions than unfamiliar faces. Regardless of their actual familiarity, the faces that the participants classified as 'familiar' elicited more negative-going N400f in the central and right temporal regions than those classified as 'unfamiliar.' The P600 was related primarily with the facial identification process. Familiar faces (regardless of lying vs. truth) elicited more positive-going P600f in the middle parietal and middle occipital regions. The results suggest that N400f and P600f play different roles in the processes involved in facial recognition. The N400f appears to be associated with both the identification (judgment of familiarity) and classification of faces, while it is likely that the P600f is only associated with the identification process (recollection of facial information). Future studies should use different experimental paradigms to validate the generalizability of the results of this study.published_or_final_versio

    Toward a university-community-school partnership model - the experience of child development fund

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    Version of RecordPublishe

    Factors contributing to officers’ fatigue in high-speed maritime craft operations

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    Author name used in this publication: Jimmy J. M. Ng2005-2006 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Second order statistics based blind source separation for artifact correction of short ERP epochs

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    ERP is commonly obtained by averaging over segmented EEC epochs. In case artifacts are present in the raw EEC measurement, pre-processing is required to prevent the averaged ERP waveform being interfered by artifacts. The simplest pre-processing approach is by rejecting trials in which presence of artifact is detected. Alternatively artifact correction instead of rejection can be performed by blind source separation, so that waste of ERP trials is avoided. In this paper, we propose a second order statistics based blind source separation approach to ERP artifact correction. Comparing with blind separation using independent component analysis, second order statistics based method does not rely on higher order statistics or signal entropy, and therefore leads to more robust separation even if only short epochs are available.published_or_final_versio

    Eye gaze and social decision making: behavioral and fMRI studies

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    Poster Session: no. 4444INTRODUCTION: Recent behavioral studies showed that people make more prosocial behaviors when observing eye-like stimuli (Haley & Fessler, 2005). On the other hand, gaze direction has been found to play an important role in social interaction (Carlin & Calder, 2013; Itier & Batty, 2009). Here, we aimed to investigate whether and how social decision making is influenced by ...postprin

    Age-related differences in neural activities during risk taking as revealed by functional MRI

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    Previous research has clearly documented that risky decision making is different in young and older adults. Yet, there has been a relative dearth of research that seeks to understand such age-related changes in the neural activities associated with risk taking. To address this research issue, 21 men (12 young men, mean age 29.9±6.2 years and 9 older men, mean age 65.2±4.2 years) performed a risky-gains task while their brain activities were monitored by an fMRI scanner. The older adults, relative to their younger peers, presented with contralateral prefrontal activity, particularly at the orbitofrontal cortex. Furthermore, stronger activation of the right insula was observed for the older-aged participants compared to the younger-aged adults. The findings of this study are consistent with the a priori speculations established in accordance with the HAROLD model as well as previous findings. Findings of this study suggest that when making risky decisions, there may be possible neuropsychological mechanisms underlying the change in impulsive and risk-taking behaviors during the course of natural ageing. © 2007 The Author(s).published_or_final_versio

    Neural Correlates of the Outcome Processing of Dishonest Choices: An fMRI and ERP study

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    A dishonest person often utilizes another person’s obliviousness to appropriate the property that belongs to the other person. Previous researchers have studied the making of a dishonest choice and the manipulation of truthful information. Here, we have investigated the neural correlates of processing the outcomes of dishonest decisions. Participants in this study were asked to interact with counterparts in an economic game. They could accept the counterparts’ proposals on how to divide the profits (honest choice) or choose the alternative plan that was advantageous to themselves (dishonest choice), playing to the ignorance of their counterparts who had a 50% chance of detecting the situation. Successful dishonest choices (not being detected) would bring large rewards, whereas honest choices would lead to less of a reward, and failed dishonest choices (being caught) would result in no reward. Participants’ neural responses during the outcome presentations were recorded by functional magnetic resonance imaging (fMRI) and event-related potential (ERP) methods in different sessions. We found that the outcomes of successful dishonest (vs. honest) choices elicited stronger activations in the ventral striatum and posterior cingulate cortex and a smaller ERP component called feedback-related negativity (FRN), which suggests that positive outcome evaluation and attention processing were aroused by successful dishonest choices. Moreover, the outcomes of failed dishonest (relative to honest) choices were associated with different neural response patterns in the medial orbitofrontal cortex and P3b ERP component between human and computer counterparts, suggesting that processing the output of social decision making (playing human) is different from that of risk taking (playing computer). The findings advanced our understanding about the neural processing of outcome presentation after a dishonest choice has been made.published_or_final_versio

    Mindfulness Trait Predicts Neurophysiological Reactivity Associated with Negativity Bias: An ERP Study

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    This study explored the relationship of mindfulness trait with the early and late stages of affective processing, by examining the two corresponding ERP components, P2 and LPP, collected from twenty-two male Chinese participants with a wide range of meditation experiences. Multiple regression analyses was performed on the mindfulness scores, as measured by CAMS-R, with the subjective affective ratings and ERP data collected during an emotion processing task. The results showed that increased mindfulness scores predicted increased valence ratings of negative stimuli (less negative), as well as increased P2 amplitudes at the frontocentral location for positive compared to negative stimuli. Based on these findings, a plausible mechanism of mindfulness in reducing negativity bias was discussed. Moreover, our results replicated previous findings on the age-related increase of P2 amplitudes at the frontal sites for positive compared to neutral stimuli. Since the locations at which P2 amplitudes were found as associated with age and mindfulness differed, as did the emotional contents of the stimuli being compared, indicating that the effect of age did not confound our findings on mindfulness and the two factors might operate on early affective processing from distinct sources and mechanisms.published_or_final_versio
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