P. Matthew Bronstad

Are attractive men's faces masculine or feminine? The importance of type of facial stimuli.

The authors investigated whether differences in facial stimuli could explain the inconsistencies in the facial attractiveness literature regarding whether adults prefer more masculine- or more feminine-looking male faces. Their results demonstrated that use of a female average to dimorphically transform a male facial average produced stimuli that did not accurately reflect the relationship between masculinity and attractiveness. In contrast, use of averages of masculine males and averages of feminine males produced stimuli that did accurately reflect the relationship between masculinity and attractiveness. Their findings suggest that masculinity contributes more to male facial attractiveness than does femininity, but future research should investigate how various combinations of facial cues contribute to male facial attractiveness.

Driving with central field loss I: effect of central scotomas on responses to hazards.

OBJECTIVES To determine how central field loss (CFL) affects reaction time to pedestrians and to test the hypothesis that scotomas lateral to the preferred retinal locus will delay detection of hazards approaching from that side. METHODS Participants with binocular CFL (scotoma diameter, 7°-25°; visual acuity, 0.3-1.0 logMAR) using lateral preferred retinal fixation loci and matched controls with normal vision drove in a simulator for approximately 1½ hours per session for 2 sessions a week apart. Participants responded to frequent virtual pedestrians who appeared on either the left or right sides and approached the participants lane on a collision trajectory that, therefore, caused them to remain in approximately the same area of the visual field. RESULTS The study included 11 individuals with CFL and 11 controls with normal vision. The CFL participants had more detection failures for pedestrians who appeared in areas of visual field loss than did controls in corresponding areas (6.4% vs 0.2%). Furthermore, the CFL participants reacted more slowly to pedestrians in blind than nonscotomatous areas (4.28 vs 2.43 seconds, P < .001) and overall had more late and missed responses than controls (29% vs 3%, P < .001). Scotoma size and contrast sensitivity predicted outcomes in blind and seeing areas, respectively. Visual acuity was not correlated with response measures. CONCLUSIONS In addition to causing visual acuity and contrast sensitivity loss, the central scotoma per se delayed hazard detection even though small eye movements could potentially compensate for the loss. Responses in nonscotomatous areas were also delayed, although to a lesser extent, possibly because of the eccentricity of fixation. Our findings will help practitioners advise patients with CFL about specific difficulties they may face when driving.

Beauty is in the 'we' of the beholder: Greater agreement on facial attractiveness among close relations

Scientific research on facial attractiveness has focused primarily on elucidating universal factors to which all raters respond consistently. However, recent work has shown that there is also substantial disagreement between raters, highlighting the importance of determining how attractiveness preferences vary among different individuals. We conducted a typical attractiveness ratings study, but took the unusual step of recruiting pairs of subjects who were spouses, siblings, or close friends. The agreement between pairs of affiliated friends, siblings, and spouses was significantly greater than between pairs of strangers drawn from the same race and culture, providing evidence that facial-attractiveness preferences are socially organized.

First Impressions From Faces Among U.S. and Culturally Isolated Tsimane’ People in the Bolivian Rainforest

The authors examined the generalizability of first impressions from faces previously documented in industrialized cultures to the Tsimane’ people in the remote Bolivian rainforest. Tsimane’ as well as U.S. judges showed within-culture agreement in impressions of attractiveness, babyfaceness, and traits (healthy, intelligent/knowledgeable, dominant/respected, and sociable/warm) of own-culture faces. Both groups also showed within-culture agreement for impressions of other-culture faces, although it was weaker than for own-culture faces, particularly among Tsimane’ judges. Moreover, there was between-culture agreement, particularly for Tsimane’ faces. Use of facial attractiveness to judge traits contributed to agreement within and between cultures but did not fully explain it. Furthermore, Tsimane’, like U.S., judges showed a strong attractiveness halo in impressions of faces from both cultures as well as the babyface stereotype, albeit more weakly. In addition to cross-cultural similarities in trait impressions from faces, supporting a universal mechanism, some effects were moderated by perceiver and face culture, consistent with perceiver attunements conditioned by culturally specific perceptual learning.

Sex differences in the anatomical locations of human body scarification and tattooing as a function of pathogen prevalence

Abstract Pathogen prevalence can affect human mate selection because pathogen severity limits the number of high-quality pathogen-resistant mates. This creates a selection pressure to fashion mechanisms to identify and select pathogen-resistant mates. Gangestad and Buss have suggested that attractiveness indicates pathogen resistance. Humans in many instances enhance their attractiveness by using permanent body markings, such as tattooing and scarification. We hypothesized that as pathogen severity increases, so should permanent marking of body areas that are attended to for evaluating attractiveness and mate quality. Females were predicted to scarify their breasts and stomachs (due to the stomach being a component of waist-to-hip ratio), both indicative of youthfulness and fertility. Males were predicted to scarify those body parts indicative of sexual maturity and strength, such as the face, shoulders, and arms. Cross-cultural data revealed that pathogen prevalence predicts female stomach scarification independent of polygyny, famine, and social class stratification. The relationship between scarification of body parts and pathogen prevalence was not evident for males. These findings, based upon between-society comparisons, suggest that stomach scarification could act as a signal of female mate quality in societies that encounter a high prevalence of pathogens.

Computational Models of Facial Attractiveness Judgments

We designed two computational models to replicate human facial attractiveness ratings. The primary model used partial least squares (PLS) to identify image factors associated with facial attractiveness from facial images and attractiveness ratings of those images. For comparison we also made a model similar to previous models of facial attractiveness, in that it used manually derived measurements between features as inputs, though we took the additional step of dimensionality reduction via principal component analysis (PCA) and weighting of PCA dimensions via a perceptron. Strikingly, both models produced estimates of facial attractiveness that were indistinguishable from human ratings. Because PLS extracts a small number of image factors from the facial images that covary with attractiveness ratings of the images, it is possible to determine the information used by the model. The image factors that the model discovered correspond to two of the main contemporary hypotheses of averageness judgments: facial attractiveness and sexual dimorphism. In contrast, facial symmetry was not important to the model, and an explicit feature-based measurement of symmetry was not correlated with human judgments of facial attractiveness. This provides novel evidence for the importance of averageness and sexual dimorphism, but not symmetry, in human judgments of facial attractiveness.

Skin and bones: The contribution of skin tone and facial structure to racial prototypicality ratings.

Previous research reveals that a more ‘African’ appearance has significant social consequences, yielding more negative first impressions and harsher criminal sentencing of Black or White individuals. This study is the first to systematically assess the relative contribution of skin tone and facial metrics to White, Black, and Korean perceivers’ ratings of the racial prototypicality of faces from the same three groups. Our results revealed that the relative contribution of metrics and skin tone depended on both perceiver race and face race. White perceivers’ racial prototypicality ratings were less responsive to variations in skin tone than were Black or Korean perceivers’ ratings. White perceivers ratings’ also were more responsive to facial metrics than to skin tone, while the reverse was true for Black perceivers. Additionally, across all perceiver groups, skin tone had a more consistent impact than metrics on racial prototypicality ratings of White faces, with the reverse for Korean faces. For Black faces, the relative impact varied with perceiver race: skin tone had a more consistent impact than metrics for Black and Korean perceivers, with the reverse for White perceivers. These results have significant implications for predicting who will experience racial prototypicality biases and from whom.

Statistical analysis of subjective preferences for video enhancement

Measuring preferences for moving video quality is harder than for static images due to the fleeting and variable nature of moving video. Subjective preferences for image quality can be tested by observers indicating their preference for one image over another. Such pairwise comparisons can be analyzed using Thurstone scaling (Farrell, 1999). Thurstone (1927) scaling is widely used in applied psychology, marketing, food tasting and advertising research. Thurstone analysis constructs an arbitrary perceptual scale for the items that are compared (e.g. enhancement levels). However, Thurstone scaling does not determine the statistical significance of the differences between items on that perceptual scale. Recent papers have provided inferential statistical methods that produce an outcome similar to Thurstone scaling (Lipovetsky and Conklin, 2004). Here, we demonstrate that binary logistic regression can analyze preferences for enhanced video.

Visual Attention Measures Predict Pedestrian Detection in Central Field Loss: A Pilot Study

Purpose The ability of visually impaired people to deploy attention effectively to maximize use of their residual vision in dynamic situations is fundamental to safe mobility. We conducted a pilot study to evaluate whether tests of dynamic attention (multiple object tracking; MOT) and static attention (Useful Field of View; UFOV) were predictive of the ability of people with central field loss (CFL) to detect pedestrian hazards in simulated driving. Methods 11 people with bilateral CFL (visual acuity 20/30-20/200) and 11 age-similar normally-sighted drivers participated. Dynamic and static attention were evaluated with brief, computer-based MOT and UFOV tasks, respectively. Dependent variables were the log speed threshold for 60% correct identification of targets (MOT) and the increase in the presentation duration for 75% correct identification of a central target when a concurrent peripheral task was added (UFOV divided and selective attention subtests). Participants drove in a simulator and pressed the horn whenever they detected pedestrians that walked or ran toward the road. The dependent variable was the proportion of timely reactions (could have stopped in time to avoid a collision). Results UFOV and MOT performance of CFL participants was poorer than that of controls, and the proportion of timely reactions was also lower (worse) (84% and 97%, respectively; p = 0.001). For CFL participants, higher proportions of timely reactions correlated significantly with higher (better) MOT speed thresholds (r = 0.73, p = 0.01), with better performance on the UFOV divided and selective attention subtests (r = −0.66 and −0.62, respectively, p<0.04), with better contrast sensitivity scores (r = 0.54, p = 0.08) and smaller scotomas (r = −0.60, p = 0.05). Conclusions Our results suggest that brief laboratory-based tests of visual attention may provide useful measures of functional visual ability of individuals with CFL relevant to more complex mobility tasks.

Factors Affecting Enhanced Video Quality Preferences

The development of video quality metrics requires methods for measuring perceived video quality. Most of these metrics are designed and tested using databases of images degraded by compression and scored using opinion ratings. We studied video quality preferences for enhanced images of normally-sighted participants using the method of paired comparisons with a thorough statistical analysis. Participants (n=40) made pair-wise comparisons of high definition video clips enhanced at four different levels using a commercially available enhancement device. Perceptual scales were computed with binary logistic regression to estimate preferences for each level and to provide statistical inference of the differences among levels and the impact of other variables. While moderate preference for enhanced videos was found, two unexpected effects were also uncovered: 1) participants could be broadly classified into two groups: a) those who preferred enhancement (“Sharp”) and b) those who disliked enhancement (“Smooth”) and 2) enhancement preferences depended on video content, particularly for human faces to be enhanced less. The results suggest that algorithms to evaluate image quality (at least for enhancement) may need to be adjusted or applied differentially based on video content and viewer preferences. The possible impact of similar effects on image quality of compressed video needs to be evaluated.