Facial expression processing in developmental prosopagnosia

<p>Individuals with developmental prosopagnosia experience lifelong deficits recognising facial identity, but whether their ability to process facial expression is also impaired is unclear. Addressing this issue is key for understanding the core deficit in developmental prosopagnosia, and for advancing knowledge about the mechanisms and development of normal face processing. In this thesis, I report two online studies on facial expression processing with large samples of prosopagnosics. In Study 1, I compared facial expression and facial identity perception in 124 prosopagnosics and 133 controls. I used three perceptual tasks including simultaneous matching, sequential matching, and sorting. I also measured inversion effects to examine whether prosopagnosics rely on typical face mechanisms. Prosopagnosics showed subtle deficits with facial expression, but they performed worse with facial identity. Prosopagnosics also showed reduced inversion effects for facial identity but normal inversion effects for facial expression, suggesting they use atypical mechanisms for facial identity but normal mechanisms for facial expression. In Study 2, I extended the findings of Study 1 by assessing facial expression recognition in 78 prosopagnosics and 138 controls. I used four labelling tasks that varied on whether the facial expressions were basic (e.g., happy) or complex (e.g., elated), and whether they were displayed via static (i.e., images) or dynamic (i.e., video clips) stimuli. Prosopagnosics showed subtle deficits with basic expressions but performed normally with complex expressions. Further, prosopagnosics did not show reduced inversion effects for both types of expressions, suggesting they use similar recognition mechanisms as controls. Critically, the subtle expression deficits that prosopagnosics showed in both studies can be accounted for by autism traits, suggesting that expression deficits are not a feature of prosopagnosia per se. I also provide estimates of the prevalence of deficits in facial expression perception (7.70%) and recognition (2.56% - 5.13%) in prosopagnosia, both of which suggest that facial expression processing is normal in the majority of prosopagnosics. Overall, my thesis demonstrates that facial expression processing is not impaired in developmental prosopagnosia, and suggests that facial expression and facial identity processing rely on separate mechanisms that dissociate in development.</p>

Facial expression processing in developmental prosopagnosia

<p>Individuals with developmental prosopagnosia experience lifelong deficits recognising facial identity, but whether their ability to process facial expression is also impaired is unclear. Addressing this issue is key for understanding the core deficit in developmental prosopagnosia, and for advancing knowledge about the mechanisms and development of normal face processing. In this thesis, I report two online studies on facial expression processing with large samples of prosopagnosics. In Study 1, I compared facial expression and facial identity perception in 124 prosopagnosics and 133 controls. I used three perceptual tasks including simultaneous matching, sequential matching, and sorting. I also measured inversion effects to examine whether prosopagnosics rely on typical face mechanisms. Prosopagnosics showed subtle deficits with facial expression, but they performed worse with facial identity. Prosopagnosics also showed reduced inversion effects for facial identity but normal inversion effects for facial expression, suggesting they use atypical mechanisms for facial identity but normal mechanisms for facial expression. In Study 2, I extended the findings of Study 1 by assessing facial expression recognition in 78 prosopagnosics and 138 controls. I used four labelling tasks that varied on whether the facial expressions were basic (e.g., happy) or complex (e.g., elated), and whether they were displayed via static (i.e., images) or dynamic (i.e., video clips) stimuli. Prosopagnosics showed subtle deficits with basic expressions but performed normally with complex expressions. Further, prosopagnosics did not show reduced inversion effects for both types of expressions, suggesting they use similar recognition mechanisms as controls. Critically, the subtle expression deficits that prosopagnosics showed in both studies can be accounted for by autism traits, suggesting that expression deficits are not a feature of prosopagnosia per se. I also provide estimates of the prevalence of deficits in facial expression perception (7.70%) and recognition (2.56% - 5.13%) in prosopagnosia, both of which suggest that facial expression processing is normal in the majority of prosopagnosics. Overall, my thesis demonstrates that facial expression processing is not impaired in developmental prosopagnosia, and suggests that facial expression and facial identity processing rely on separate mechanisms that dissociate in development.</p>

Within-person variability can improve the identification of unfamiliar faces across changes in viewpoint

Unfamiliar face identification is concerningly error prone, especially across changes in viewing conditions. Within-person variability has been shown to improve matching performance for unfamiliar faces, but this has only been demonstrated using images of a front view. In this study, we test whether the advantage of within-person variability from front views extends to matching to target images of a face rotated in view. Participants completed either a simultaneous matching task (Experiment 1) or a sequential matching task (Experiment 2) in which they were tested on their ability to match the identity of a face shown in an array of either one or three ambient front-view images, with a target image shown in front, three-quarter, or profile view. While the effect was stronger in Experiment 2, we found a consistent pattern in match trials across both experiments in that there was a multiple image matching benefit for front, three-quarter, and profile-view targets. We found multiple image effects for match trials only, indicating that providing observers with multiple ambient images confers an advantage for recognising different images of the same identity but not for discriminating between images of different identities. Signal detection measures also indicate a multiple image advantage despite a more liberal response bias for multiple image trials. Our results show that within-person variability information for unfamiliar faces can be generalised across views and can provide insights into the initial processes involved in the representation of familiar faces.

Epinephrine administration for adult out-of-hospital cardiac arrest patients with refractory shockable rhythm: time-dependent propensity score-sequential matching analysis from a nationwide population-based registry

Aims Little is known about the effect of prehospital epinephrine administration in out-of-hospital cardiac arrest (OHCA) patients with refractory shockable rhythm, for whom initial defibrillation was unsuccessful. Methods and results This study using Japanese nationwide population-based registry included all adult OHCA patients aged ≥18 years with refractory shockable rhythm between January 2014 and December 2017. Patients with or without epinephrine during cardiac arrest were sequentially matched using a risk set matching based on the time-dependent propensity scores within the same minute. The primary outcome was 1-month survival. The secondary outcomes included 1-month survival with favourable neurological outcome (cerebral performance category scale: 1 or 2) and prehospital return of spontaneous circulation (ROSC). Of the 499 944 patients registered in the database during the study period, 22 877 were included. Among them, 8467 (37.0%) received epinephrine. After time-dependent propensity score-sequential matching, 16 798 patients were included in the matched cohort. In the matched cohort, positive associations were observed between epinephrine and 1-month survival [epinephrine: 17.3% (1454/8399) vs. no epinephrine: 14.6% (1224/8399); RR 1.22 (95% confidence interval, CI: 1.13–1.32)] and prehospital ROSC [epinephrine: 22.2% (1868/8399) vs. no epinephrine: 10.7% (900/8399); RR 2.07 (95% CI: 1.91–2.25)]. No significant positive association was observed between epinephrine and favourable neurological outcome [epinephrine: 7.8% (654/8399) vs. no epinephrine: 7.1% (611/8399); RR 1.13 (95% CI 0.998–1.27)]. Conclusion Using the nationwide population-based registry with time-dependent propensity score-sequential matching analysis, prehospital epinephrine administration in adult OHCA patients with refractory shockable rhythm was positively associated with 1-month survival and prehospital ROSC.

Parallel Scalable Approximate Matching Algorithm for Network Intrusion Detection Systems

Matching algorithms are working to find the exact or the approximate matching between text “T” and pattern “P”, due to the development of a computer processor, which currently contains a set of multi-cores, multitasks can be performed simultaneously. This technology makes these algorithms work in parallel to improve their speed matching performance. Several exact string matching and approximate matching algorithms have been developed to work in parallel to find the correspondence between text “T” and pattern “P”. This paper proposed two models: First, parallelized the Direct Matching Algorithm (PDMA) in multi-cores architecture using OpenMP technology. Second, the PDMA implemented in Network Intrusion Detection Systems (NIDS) to enhance the speed of the NIDS detection engine. The PDMA can be achieved more than 19.7% in parallel processing time compared with sequential matching processing. In addition, the performance of the NIDS detection engine improved for more than 8% compared to the current SNORT-NIDS detection engine

Subjective Homophily and the Fixtures Problem

The Stable Fixtures problem (Irving and Scott (2007)) is a generalized matching model that nests the well-known Stable Roommates, Stable Marriage, and College Admissions problems as special cases. This paper extends a result of the Stable Roommates problem to demonstrate that a class of homophilic preferences with an appealing psychological interpretation is sufficient to ensure that starting from an arbitrary matching, a decentralized process of allowing the sequential matching of randomly chosen blocking pairs will converge to a pairwise-stable matching with probability one. Strategic implications of this class of preferences are examined and further possible generalizations and directions for future research are discussed.