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

Statistical analysis of subjective preferences for video enhancement

ABSTRACT Traditional Thurstone scaling (1927) constructs a perceptual scale from pairwise comparisons without providing statistical inferences. We show that subjective preferences for moving video using pairwise comparisons can be analyzed to construct a perceptual scale and provide the statistical significance of preference differences. Two statistical methods (binary logistic regression and linear regression) are described. Data sets from two studies are used to demonstrate the perceptual scale construction from the traditional Thurstone method and from the described statistical methods. Both the studies showed videos on two side-by-side TVs. Four enhancement levels (Off, Low, Medium and High) were applied to the videos using a commercial device. Subjects made pairwise comparisons to indicate their preference of one video over another. The perceptual scales constructed from the three methods were comparable, except when there were cells missing from the preference matrix. Binary logistic regression easily permitted modeling of additional factors, such as side bias. Video quality can be systematically assessed using pairwise comparisons and statistical methods that permits construction of a perceptual scale and provide statistical significance for the compared levels

CFL2 Vertical scotoma

Reaction time data for study in press at PLoS One entitled "Driving with Central Visual Field Loss II: How Scotomas Above or Below the Preferred Retinal Locus (PRL) Affect Hazard Detection in a Driving Simulator"

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

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 attrac- tiveness 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

Relationship between proportion of timely reactions and attention measures for CFL participants.

<p><b>(a)</b> UFOV divided attention threshold duration, <b>(b)</b> UFOV selective attention threshold duration, <b>(c)</b> UFOV divided attention difference score, <b>(d)</b> UFOV selective attention difference score, and <b>(e)</b> the MOT task. Better performance on the pedestrian detection task was associated with better performance on each of the attention tests. UFOV scores are plotted on reversed axes so that better performance is at the right hand side of the x-axis for all figures. Thick black line shows the linear trend.</p

Demographic and visual characteristics of normally-sighted (n = 11) and CFL (n = 11) study participants.

<p>^*Fisher's Exact Test for sex; Student's independent t-tests for other variables.</p

The car and truck targets from the UFOV central identification task.

<p>The targets differed only in whether two thin lines were present in the top left area of each outline, making this task difficult for participants with CFL.</p