Eric Egan

From the heart to the mind's eye: Cardiac vagal tone is related to visual perception of fearful faces at high spatial frequency☆

The neurovisceral integration model (Thayer and Lane, 2000) proposes that vagally mediated heart rate variability (HRV)--an index of cardiac vagal tone--is associated with autonomic flexibility and emotional self-regulation. Two experiments examined the relationship between vagally mediated HRV and visual perception of affectively significant stimuli at different spatial frequencies. In Experiment 1, HRV was positively correlated with superior performance discriminating the emotion of affectively significant (i.e., fearful) faces at high spatial frequency (HSF). In Experiment 2, processing goals moderated the relationship between HRV and successful discrimination of HSF fearful faces. In contrast to Experiment 1, discriminating the expressiveness of HSF fearful faces was not correlated with HRV. The current research suggests that HRV is positively associated with superior visual discrimination of affectively significant stimuli at high spatial frequency, and this relationship may be sensitive to the top-down influence of different processing goals.

Magically deceptive biological motion—the French Drop Sleight

Intentional deception, as is common in the performance of magic tricks, can provide valuable insight into the mechanisms of perception and action. Much of the recent investigations into this form of deception revolve around the attention of the observer. Here, we present experiments designed to investigate the contributions of the performer to the act of deception. An experienced magician and a naïve novice performed a classic sleight known as the French Drop. Video recordings of the performance were used to measure the quality of the deception—e.g., if a non-magician observer could discriminate instances where the sleight was performed (a deceptive performance) from those where it was not (a veridical performace). During the performance we recorded the trajectory of the hands and measured muscle activity via EMG to help understand the biomechanical mechanisms of this deception. We show that expertise plays a major role in the quality of the deception and that there are significant variations in the motion and muscular behaviors between successful and unsuccessful performances. Smooth, minimal movements with an exaggerated faux-transfer of muscular tension were characteristic of better deception. This finding is consistent with anecdotal reports and the magic performance literature.

Local Surface Patch Classification Using Multilinear PCA+LDA on High-Order Image Structures Compared to Human Observers

What information do we use to determine the curvatures of local surface patches? In a 5-AFC decision task, observers judged the curvatures of local surface patches viewed through an aperture, including Bells, Dimples, Furrows, Humps, and Saddles that were cylindrically projected onto a sphere. Numerous high-order image structures were computed from stimulus luminance values. Classical and Multilinear PCA were performed on image structures, which were dimensionally degraded until mean model performances (i.e., proportions of correct discriminations) matched the mean performance of observers. The posterior probability distributions of the LDA classifiers were then correlated with human error confusions. Among the image structures that were examined, the strongest predictors of human performance involved 2nd-order derivatives of the luminance patterns. Using more than one image structure at a time did not reliably improve model prediction, leading us to choose Laplacian of Gaussian arrays and Multilinear PCA+LDA for further analysis. The model accounted for approximately 33% of the error confusions that were predicted by independent human observers. In other words, the model was about 1/3 as reliable as the test-retest reliability of independent human observations. It appears as though humans may use information analogous to high-order image structures to judge local surface contours, however the exact information guiding our perceptual judgments remains uncertain. Meeting abstract presented at VSS 2015.