Effects of peripheral eccentricity and head orientation on gaze discrimination

This is an Accepted Manuscript of an article published by Taylor & Francis in Social Neuroscience on 13 Jan 2015, available online: http://www.tandfonline.com/10.1080/13506285.2014.990545.Visual search tasks support a special role for direct gaze in human cognition, while classic gaze judgement tasks suggest the congruency between head orientation and gaze direction plays a central role in gaze perception. Moreover, whether gaze direction can be accurately discriminated in the periphery using covert attention is unknown. In the present study, individual faces in frontal and in deviated head orientations with a direct or an averted gaze were flashed for 150 ms across the visual fieldparticipants focused on a centred fixation while judging the gaze direction. Gaze discrimination speed and accuracy varied with head orientation and eccentricity. The limit of accurate gaze discrimination was less than ±6° eccentricity. Response times suggested a processing facilitation for direct gaze in fovea, irrespective of head orientation, however, by ±3° eccentricity, head orientation started biasing gaze judgements, and this bias increased with eccentricity. Results also suggested a special processing of frontal heads with direct gaze in central vision, rather than a general congruency effect between eye and head cues. Thus, while both head and eye cues contribute to gaze discrimination, their role differs with eccentricity

Effects of Gender and Gaze Direction on the Visual Exploration of Male and Female Bodies

The present study used eye-tracking to investigate whether a model’s gaze direction influences the way observers look at the entire body of the model and how this interacts with the observer and the model’s gender. Participants viewed individual male and female computer agents during both a free-viewing task and a rating task to evaluate the attractiveness of each character. The results indicated that both male and female participants primarily gazed at the models’ faces. Participants also spent more time scanning the face when rating the attractiveness of each model. Observers tended to scan faces with a direct gaze longer than faces with an averted gaze for both the free-viewing and attractiveness rating tasks. Lastly, participants evaluated models with a direct gaze as more attractive than models with an averted gaze. As these results occurred for pictures of computer agents, and not actual people, this suggests that direct gaze, and faces in general, are powerful for engaging attention. In summary, both task requirements and gaze direction modified face viewing preference

Eye gaze and head orientation modulate the inhibition of return for faces

The final publication is available at Springer via https://dx.doi.org/10.3758/s13414-015-0961-y.The present study used an inhibition of return (IOR) spatial cueing paradigm to examine how gaze direction and head orientation modulate attention capture for human faces. Target response time (RT) was measured after the presentation of a peripheral cue, which was either a face (with frontfacing or averted gaze, in either frontal head view or averted head view) or a house (control). Participants fixated on a centred cross at all times and responded via button press to a peripheral target after a variable stimulus onset asynchrony (SOA) from the stimulus cue. At the shortest SOA (150 ms), RTs were shorter for faces than houses, independent of an IOR response, suggesting a cue-based RT advantage elicited by faces. At the longest SOA (2400 ms), a larger IOR magnitude was found for faces compared to houses. Both the cue-based RT advantage and later IOR responses were modulated by gaze-head congruency; these effects were strongest for frontal gaze faces in frontal head view, and for averted gaze faces in averted head view. Importantly, participants were not given any specific information regarding the stimuli, nor were they told the true purpose of the study. These findings indicate that the congruent combination of head and gaze direction influence the exogenous attention capture of faces during inhibition of return.These findings indicate that the congruent combination of head and gaze direction influence the exogenous attention capture of faces during inhibition of return.||the Ontario government (Early Researcher Award||ER11-08-172), the Canada Foundation for Innovation (CFI, #213322)||and the Canada Research Chair (CRC, #959-213322) program to RJI||as well as by a doctoral NSERC grant to KNN

The Effects of Eye Gaze and Head Orientation On Covert Attention Capture

The direction of someone’s eye gaze plays a fundamental role during social interactions and may function to capture and engage attention in the environment. Research has shown that direct eye gaze can preferentially attract visuospatial attention compared to averted gaze, while other research has shown that the congruency between head orientation and gaze direction plays a central role in determining where a person is looking. The majority of previous research examining the perception of gaze direction has predominantly measured overt attention, either through visual search paradigms, or other gaze judgment tasks when targets are directly fixated. However, it is unknown whether gaze direction can be accurately discriminated using covert attention, when stimuli are located outside the focus of attention. This thesis presents a series of studies examining whether and to what extent gaze direction and head orientation capture covert attention in the periphery. Chapter 2 contained four experiments examining gaze detection in the horizontal periphery. Individual faces with a direct- or an averted gaze were flashed for 150 ms across various horizontal eccentricities along the visual field while participants judged whether the face was looking straight or to the side. Fixation on a centred cross was enforced using an eye-tracker, ensuring the use of covert attention. Gaze detection speed and accuracy varied with stimulus type and eccentricity. Accurate gaze detection was achieved all the way to ±10.5° eccentricity when face photographs were highly symmetrical and controlled for visual contrast and luminance (Experiment 1a), but only to ±4.5° eccentricity when using natural face photographs (Experiments 1b, 1c, and 1d). By ±3º of eccentricity, head orientation started biasing gaze judgments, and this bias increased with eccentricity so that beyond central vision gaze judgment was primarily made on the basis of head orientation. However, when presented at the fovea, direct gaze was generally detected faster than averted gaze. Results also suggested a facilitated processing of frontal heads with direct gaze in both central and peripheral vision. Chapter 3 contained three experiments that examined gaze detection in the vertical periphery. These experiments used the same paradigm as in Chapter 2, except with presenting stimuli across various vertical eccentricities (only natural face photographs were used). Gaze was detected above chance level up to ±3° eccentricity when using frontal heads (Experiment 2a), but over ±6° eccentricity when using deviated heads (Experiment 2b); Experiment 2b also showed that head orientation did not play a strong role in biasing gaze judgments. However, it was demonstrated that, beyond foveal vision, head orientation influenced gaze judgments when both head orientations were tested together (Experiment 2c), and that gaze was discriminated accurately only within central vision (~3°-4.5° eccentricity). Again, there was a special processing of frontal heads with direct gaze. Chapter 4 contained two experiments that investigated how gaze direction and head orientation influenced attention capture using an inhibition of return (IOR) spatial cueing paradigm. Target response time (RT) was measured after the presentation of a stimulus cue (150 ms situated 4.5° horizontally to either left or right of fixation), which was either a face (with direct- or averted gaze) or a house (control). Participants fixated on a centred cross at all times and responded via button press to a peripheral target after a variable stimulus onset asynchrony (SOA) from the stimulus cue. At the shortest SOA (150 ms), RTs were shorter for faces than houses, independent of an IOR response, suggesting a priming effect elicited by faces. At the longest SOA (2400 ms), a larger IOR magnitude was found for faces compared to houses. Both the priming effect and later IOR responses were modulated by gaze-head congruency; these effects were strongest for direct gaze faces with frontal heads (Experiment 3a), and for averted gaze faces with deviated heads (Experiment 3b). Overall, the series of studies in this thesis indicate that gaze direction and head orientation can be powerful social cues for capturing and engaging attention, and both contribute to gaze detection in the environment, but their roles differ with eccentricity

Asymmetry in Gaze Direction Discrimination Between the Upper and Lower Visual Fields

To view the final version of this © SAGE publication go here: https://dx.doi.org/10.1177/0301006616686989Previous research has shown that gaze direction can only be accurately discriminated within parafoveal limits (∼5° eccentricity) along the horizontal visual field. Beyond this eccentricity, head orientation seems to influence gaze discrimination more than iris cues. The present study examined gaze discrimination performance in the upper visual field (UVF) and lower visual field (LVF), and whether head orientation affects gaze judgments beyond parafoveal vision. Direct and averted gaze faces, in frontal and deviated head orientations, were presented for 150 ms along the vertical meridian while participants maintained central fixation during gaze discrimination judgments. Gaze discrimination was above chance level at all but one eccentricity for the two gaze-head congruent conditions. In contrast, for the incongruent conditions, gaze was discriminated above chance only from -1.5° to +3°, with an asymmetry between the UVF and LVF. Beyond foveal vision, response rates were biased toward head orientation rather than iris eccentricity, occurring in the LVF for both head orientations, and in the UVF for frontal head views. These findings suggest that covert processing of gaze direction involves the integration of eyes and head cues, with congruency of these two social cues driving response differences between the LVF and the UVF.This work was supported by NSERC (Discovery grant #418431)CFI (#213322)and the Canada Research Chair (CRC) program (#959-213322) to R. J. I.and by a Queen Elizabeth II Graduate Scholarship in Science and Technology to A. P

Initial Mix-and-Match COVID-19 Vaccination Perceptions, Concerns, and Side Effects across Canadians

Research indicates that mixing the first two doses of COVID-19 vaccine types (i.e., adenoviral vector and mRNA) produces potent immune responses against the coronavirus, but it is unclear how individuals may perceive these benefits, or whether there are different concerns compared to individuals who received two doses of the same vaccine. This research examines the demographic characteristics, psychological perceptions, and vaccination-related opinions and experiences of a large Canadian sample (N = 1002) who had received two initial doses of any COVID-19 vaccine combination. Participants included 791 (78.9%) who received two doses of the exact same brand and type of vaccine, 164 (16.4%) who received two doses of the same type of vaccine (i.e., either mRNA or adenoviral vector) but from different brands (e.g., Pfizer-BioNTech + Moderna), and 47 (4.7%) who received two doses from different types and brands of vaccine (e.g., Oxford-AstraZeneca + Pfizer-BioNTech). Results showed that, after the first vaccine dose, participants who received an adenoviral vector vaccine (e.g., Oxford-AstraZeneca) experienced the highest number of common side effects, and more severe levels of each side effect compared to those who received an mRNA vaccine (e.g., Pfizer-BioNTech or Moderna). After the second dose, participants who received Moderna as their second vaccine experienced the highest number of and most severe side effects, regardless of whether they received Moderna, Pfizer-BioNTech, or Oxford-AstraZeneca as their first dose. Real-world implications of these findings are discussed

Eliciting clinical empathy via transmission of patient-specific symptoms of Parkinson’s disease

Clinical empathy can have numerous benefits for patients, clinicians, and health-care providers. Traditional empathy training techniques (e.g. storytelling, videos, or disease simulators) are centered on the health condition rather than the individual. This condition-centric approach perpetuates the belief that the disease, rather than the patient, is at the core of the experience. This process can be ineffective in generating the ability to understand and accurately acknowledge the feelings of another. A more effective means of eliciting empathy can be through technology-mediated symptom transference for transmitting an individual patient’s actual experience, rather than a simulation, to the user—a process termed “tele-empathy.” We developed an investigational digital tele-empathy device for use toward patients with Parkinson’s disease (PD), known as SymPulse™. The device plays back muscle tremors using an armband, giving the wearer a replication of the involuntary muscle activity that a patient with PD feels. The purpose of the current study was to determine whether the SymPulse™ device could enhance feelings of empathy in test participants (wearing the device) versus control participants (not wearing the device). A sample of 45 participants (22 test; 23 control) reported their level of empathy via self-report questionnaires. Results revealed significantly higher empathy scale scores for test compared to control participants, demonstrating the effectiveness of the SymPulse™ for use in tele-empathy. The use of such technology for eliciting tele-empathy may have practical and clinical implications for providing effective training to health-care providers

A Free Open-Source Bayesian Vancomycin Dosing App for Adults: Design and Evaluation Study

BackgroundIt has been suggested that Bayesian dosing apps can assist in the therapeutic drug monitoring of patients receiving vancomycin. Unfortunately, Bayesian dosing tools are often unaffordable to resource-limited hospitals. Our aim was to improve vancomycin dosing in adults. We created a free and open-source dose adjustment app, VancoCalc, which uses Bayesian inference to aid clinicians in dosing and monitoring of vancomycin. ObjectiveThe aim of this paper is to describe the design, development, usability, and evaluation of a free open-source Bayesian vancomycin dosing app, VancoCalc. MethodsThe app build and model fitting process were described. Previously published pharmacokinetic models were used as priors. The ability of the app to predict vancomycin concentrations was performed using a small data set comprising of 52 patients, aged 18 years and over, who received at least 1 dose of intravenous vancomycin and had at least 2 vancomycin concentrations drawn between July 2018 and January 2021 at Lakeridge Health Corporation Ontario, Canada. With these estimated and actual concentrations, median prediction error (bias), median absolute error (accuracy), and root mean square error (precision) were calculated to evaluate the accuracy of the Bayesian estimated pharmacokinetic parameters. ResultsA total of 52 unique patients’ initial vancomycin concentrations were used to predict subsequent concentration; 104 total vancomycin concentrations were assessed. The median prediction error was –0.600 ug/mL (IQR –3.06, 2.95), the median absolute error was 3.05 ug/mL (IQR 1.44, 4.50), and the root mean square error was 5.34. ConclusionsWe described a free, open-source Bayesian vancomycin dosing calculator based on revisions of currently available calculators. Based on this small retrospective preliminary sample of patients, the app offers reasonable accuracy and bias, which may be used in everyday practice. By offering this free, open-source app, further prospective validation could be implemented in the near future