James C. Christensen

Smile esthetics from the layperson’s perspective

INTRODUCTION Computer-based smile esthetic surveys based on slider technology allow more precise control of variables and the possibility of obtaining continuous data. Variations in the perception of smiles from different facial perspectives have not been resolved. The objective of this study was to quantify the ideal and the range of acceptable values for smile variables judged by laypersons from a full-face perspective for comparison with lower-face data. METHODS Mirrored and symmetric male and female full faces previously determined by peers to be of average attractiveness were used. Ninety-six laypersons judged these smile variables: smile arc, buccal corridor fill, maxillary gingival display, maxillary midline to face, maxillary to mandibular midline discrepancy, overbite, central incisor gingival margin discrepancy, maxillary anterior gingival height discrepancy, incisal edge discrepancy, and cant. The judges manipulated the variables using adjustable image technology that allowed the variable to morph and appear continuous on a computer monitor. Medians for each smile variable were compiled, and the Fleiss-Cohen weighted kappa statistic was calculated to measure reliability. Multiple randomization tests with adjusted P values were used to compare these data with those for lower-face views. RESULTS Reliability ranged from 0.25 for ideal overbite to 0.60 for upper midline to face, except for upper and lower buccal corridor limits, which each had a kappa value near 0. There were no statistically significant differences between the ratings of male and female raters. The following variables showed statistically and clinically significant differences (>1 mm) when compared with the lower-face view: ideal smile arc, ideal buccal corridor, maximum gingival display, upper to lower midline, and occlusal cant. Although the smile arc values differed because of model lip curvature variations, the principle of tracking the curve of the lower lip was confirmed. For the full-face view, the raters preferred less maximum gingival display, less buccal corridor, more upper to lower midline discrepancy, and less cant of the occlusal plane. CONCLUSIONS Reliability was fair to moderate with the exception of the buccal corridor limits. Most variables showed no clinically meaningful differences from the lower-face view. The acceptable range was quite large for most variables. Detailed knowledge of the ideal values of the various variables is important and can be incorporated into orthodontic treatment to produce an optimal esthetic smile.

The effects of day-to-day variability of physiological data on operator functional state classification.

The application of pattern classification techniques to physiological data has undergone rapid expansion. Tasks as varied as the diagnosis of disease from magnetic resonance images, brain-computer interfaces for the disabled, and the decoding of brain functioning based on electrical activity have been accomplished quite successfully with pattern classification. These classifiers have been further applied in complex cognitive tasks to improve performance, in one example as an input to adaptive automation. In order to produce generalizable results and facilitate the development of practical systems, these techniques should be stable across repeated sessions. This paper describes the application of three popular pattern classification techniques to EEG data obtained from asymptotically trained subjects performing a complex multitask across five days in one month. All three classifiers performed well above chance levels. The performance of all three was significantly negatively impacted by classifying across days; however two modifications are presented that substantially reduce misclassifications. The results demonstrate that with proper methods, pattern classification is stable enough across days and weeks to be a valid, useful approach.

Neuroergonomics: the brain in action and at work.

Neuroimaging methods have steadily improved in their technical sophistication and breadth of application over the past decade. Cognitive neuroscience studies using these methods have also increased in their intricacy, and there has been growing interest in their use to examine the neural circuits supporting complex tasks representative of perception, cognition, and action as they occur in natural settings. At the same time, many fields in the biological sciences—including neuroscience—are being challenged to demonstrate their relevance to practical real-world problems. Much of the translational efforts in the area of neuroscience have been devoted to disease, namely the diagnosis and treatment of neurological, psychiatric, and other medical disorders (Editorial, 2002; Insel, 2010; Matthews et al., 2006). Yet there are many opportunities for translational neuroscience outside of medicine or health proper. One example is the application of cognitive neuroscience research to improve the design of automobiles and the safety of drivers in various traffic conditions (Lees et al., 2010). More generally, translational neuroscience is relevant to the enhancement of human performance in domains such as aviation, education, security, and the military, aswell as inmany everyday settings. Collectively, such efforts are known as neuroergonomics (Parasuraman, 2011; Parasuraman and Rizzo, 2008). Researchers and professionals in human factors and ergonomics study human capabilities and limitations, both cognitive and physical, and use that knowledge to design technologies and work environments to be safer and more usable, efficient, and enjoyable for people to interact with (Norman, 1990; Wickens and Holands, 2000). The central premise of neuroergonomics is that human factors research and practice can be enriched by consideration of theories and results from neuroscience. Some decades ago such a claim would have been considered implausible because our knowledge of human (as opposed to animal) brain function was limited and restricted to only the simplest aspects of human behavior. However, with the phenomenal growth of human cognitive, and more recently, social neuroscience, it is increasingly the case that theories of human performance can be constrained or extended by consideration of findings from the neurosciences (Gazzaniga, 2009). The relevant neuroscience techniques include neuroimaging, non-invasive brain stimulation, molecular genetics, and related methods. This knowledge is amplified by ever increasing improvements in modeling and decoding brain activity with machine learning algorithms and related computational techniques (Mitchell et al., 2004). Integration across these different methods will be a necessary step in substantially advancing the science of human performance and exploiting their potential for addressing key questions concerning brain function. Neuroergo-

Smile esthetics from patients' perspectives for faces of varying attractiveness.

INTRODUCTION Delivering an attractive smile is a key element in orthodontic patient satisfaction. Smile characteristics can be affected by the facial context. The purpose of this study was to investigate smile esthetics related to facial attractiveness and sex of the model. METHODS Attractive, average, and unattractive model faces (2 of each; 3 male, 3 female) determined by peer ratings were combined with 10 smile variables (buccal corridor, smile arc, maxillary gingival discrepancy, gingival display, incisal-edge discrepancy, cant, overbite, central-incisor gingival margin discrepancy, and maxillary midline to face, and maxillary midline to mandibular midline). Each smile characteristic was altered digitally and presented with slider technology to allow a continuous range of choices. Raters chose the ideal and the limits of acceptability. The variables were divided into 6 separate surveys and rated 96 times. Reliability was assessed by answering each question twice. RESULTS Individual smile variable reliability ranged from fair to excellent, except for the buccal corridor. Clinically significant values were defined as greater than 1.0 mm with statistical significance (P <0.05). Rater sex did not make a difference. Clinical significance was found for smile arc, gingival display, and maxillary midline to face. For females, accentuated smile arcs were preferred for the unattractive and attractive models compared with the average models. The opposite was found for male models. More gingival display was preferred for the attractive and unattractive male and female models compared with the average models. Attractive models were allowed less midline deviation. CONCLUSIONS Facial attractiveness and model sex impacted smile variables with a facial context, except for occlusal cant. These smile characteristics with a facial context should be considered when diagnosing and planning treatment for an orthodontic patient.

Validation of a Dry Electrode System for EEG

Electroencephalography (EEG) has been used for over 80 years to monitor brain activity. The basic technology of using electrodes placed on the scalp with conductive gel or paste (“wet electrodes”) has not fundamentally changed in that time. An electrode system that does not require conductive gel and skin preparation represents a major advancement in this technology and could significantly increase the utility of such a system for many human factors applications. QUASAR, Inc. (San Diego, CA) has developed a prototype dry electrode system for EEG that may well deliver on the promises of dry electrode technology; before any such system could gain widespread acceptance, it is essential to directly compare their system with conventional wet electrodes. An independent validation of dry vs. wet electrodes was conducted; in general, the results confirm that the data collected by the new system is comparable to conventional wet technology.

Lack of association between human plasma oxytocin and interpersonal trust in a prisoner's dilemma paradigm

Expanding interest in oxytocin, particularly the role of endogenous oxytocin in human social behavior, has created a pressing need for replication of results and verification of assay methods. In this study, we sought to replicate and extend previous results correlating plasma oxytocin with trust and trustworthy behavior. As a necessary first step, the two most commonly used commercial assays were compared in human plasma via the addition of a known quantity of exogenous oxytocin, with and without sample extraction. Plasma sample extraction was found to be critical in obtaining repeatable concentrations of oxytocin. In the subsequent trust experiment, twelve samples in duplicate, from each of 82 participants, were collected over approximately six hours during the performance of a Prisoner’s Dilemma task paradigm that stressed human interpersonal trust. We found no significant relationship between plasma oxytocin concentrations and trusting or trustworthy behavior. In light of these findings, previous published work that used oxytocin immunoassays without sample extraction should be reexamined and future research exploring links between endogenous human oxytocin and trust or social behavior should proceed with careful consideration of methods and appropriate biofluids for analysis.

Orthodontic appliance preferences of children and adolescents

INTRODUCTION Although attractiveness and acceptability of orthodontic appliances have been rated by adults for themselves and for adolescents, children and adolescents have not provided any substantial data. The objective of this study was to evaluate preferences and acceptability of orthodontic appliances in children and adolescents. METHODS Images of orthodontic appliances previously captured and standardized were selected and incorporated into a computer-based survey. Additional images of shaped brackets and colored elastomeric ties, as well as discolored clear elastomeric ties, were captured and incorporated onto existing survey images with Photoshop (Adobe, San Jose, Calif). The survey displayed 12 orthodontic appliance variations to 139 children in 3 age groups: 9 to 11 years (n = 45), 12 to 14 years (n = 49), and 15 to 17 years (n = 45). The subjects rated each image for attractiveness and acceptability. All images were displayed and rated twice to assess rater reliability. RESULTS Overall reliability ratings were r = 0.74 for attractiveness and k = 0.66 for acceptability. There were significant differences in bracket attractiveness and acceptability in each age group. The highest-rated appliances were clear aligners, twin brackets with colored ties, and shaped brackets with and without colored ties. Colored elastomeric ties improved attractiveness significantly over brackets without colored ties for children in the 12-to-14 year group. There was a tendency for older subjects to rate clear orthodontic appliances higher than did younger subjects. Ceramic brackets with discolored ties tended to be rated lower than ceramic brackets with new ties and scored lowest in acceptability and attractiveness in all age groups. Girls rated shaped brackets significantly higher than did boys. CONCLUSIONS Childrens preferences for orthodontic appliances differ by age and sex. Child and adolescent preferences differ from adult preferences.

Human Factors in Cyber Warfare II: Emerging Perspectives

Cyber operations offer a unique environment in which the lines between cognition and technology are constantly blurred. Within the greater research community, current work often focuses solely on the technology, often only acknowledging the human in passing, if at all. More recently, the Human Factors community has begun to address human-centered issues in cyber operations, but in comparison to technological communities, we have yet to scratch the surface. Even with publications on Cyber Human Factors gaining momentum, we still lack a complete and holistic understanding of the domain itself, creating a major gap in the field. The purpose of this panel is to continue to expand the role Human Factors in cyber research by introducing the community to current work being done, and to facilitate collaborations to drive future research. We have assembled a panel of scientists across multiple specializations in the Human Factors community to have an open discussion on how we can leverage previous work in human factors and current work in cyber operations to continue to push the bounds of the field.

Evaluation of a Dry Electrode System for Electroencephalography: Applications for Psychophysiological Cognitive Workload Assessment

Advances in state-of-the-art dry electrode technology have led to the development of a novel dry electrode system for electroencephalography (QUASAR, Inc.; San Diego, California, USA). While basic systems-level testing and comparison of this dry electrode system to conventional wet electrode systems has proved to be very favorable, very limited data has been collected that demonstrates the ability of QUASARs dry electrode system to replicate results produced in more applied, dynamic testing environments that may be used for human factors applications. In this study, QUASARs dry electrode headset was used in combination with traditional wet electrodes to determine the ability of the dry electrode system to accurately differentiate between varying levels of cognitive workload. Results show that the accuracy in cognitive workload assessment obtained with wet electrodes is comparable to that obtained with the dry electrodes.

Coadaptive aiding and automation enhance operator performance.

Objective: In this work, we expand on the theory of adaptive aiding by measuring the effectiveness of coadaptive aiding, wherein we explicitly allow for both system and user to adapt to each other. Background: Adaptive aiding driven by psycho- physiological monitoring has been demonstrated to be a highly effective means of controlling task allocation and system functioning. Psychophysiological monitoring is uniquely well suited for coadaptation, as malleable brain activity may be used as a continuous input to the adaptive system. Method: To establish the efficacy of the coadaptive system, physiological activation of adaptation was directly compared with manual activation or no activation of the same automation and cuing systems. We used interface adaptations and automation that are plausible for real-world operations, presented in the context of a multi–remotely piloted aircraft control simulation. Each participant completed 3 days of testing during 1 week. Performance was assessed via proportion of targets successfully engaged. Results: In the first 2 days of testing, there were no significant differences in performance between the conditions. However, in the third session, physiological adaptation produced the highest performance. Conclusion: By extending the data collection across multiple days, we offered enough time and repeated experience for user adaptation as well as online system adaptation, hence demonstrating coadaptive aiding. Application: The results of this work may be employed to implement more effective adaptive works-tations in a variety of work domains.