Human Preferences for Symmetry: Subjective Experience, Cognitive Conflict and Cortical Brain Activity

This study examines the links between human perceptions, cognitive biases and neural processing of symmetrical stimuli. While preferences for symmetry have largely been examined in the context of disorders such as obsessive-compulsive disorder and autism spectrum disorders, we examine various these phenomena in non-clinical subjects and suggest that such preferences are distributed throughout the typical population as part of our cognitive and neural architecture. In Experiment 1, 82 young adults reported on the frequency of their obsessive-compulsive spectrum behaviors. Subjects also performed an emotional Stroop or variant of an Implicit Association Task (the OC-CIT) developed to assess cognitive biases for symmetry. Data not only reveal that subjects evidence a cognitive conflict when asked to match images of positive affect with asymmetrical stimuli, and disgust with symmetry, but also that their slowed reaction times when asked to do so were predicted by reports of OC behavior, particularly checking behavior. In Experiment 2, 26 participants were administered an oddball Event-Related Potential task specifically designed to assess sensitivity to symmetry as well as the OC-CIT. These data revealed that reaction times on the OC-CIT were strongly predicted by frontal electrode sites indicating faster processing of an asymmetrical stimulus (unparallel lines) relative to a symmetrical stimulus (parallel lines). The results point to an overall cognitive bias linking disgust with asymmetry and suggest that such cognitive biases are reflected in neural responses to symmetrical/asymmetrical stimuli.

The MSSM with a softly broken U(2)^3 flavor symmetry

In this article we review the phenomenological consequences of radiative flavor-violation (RFV) in the MSSM. In the model under consideration the U(3)^3 flavor symmetry of the gauge sector is broken in a first step to U(2)^3 by the top and bottom Yukawa couplings of the superpotential (and possibly also by the bilinear SUSY-breaking terms). In a second step the remaining U(2)^3 flavor symmetry is softly broken by the trilinear A-terms in order to obtain the measured quark masses and the CKM matrix of the Standard Model (SM) at low energies. The phenomenological implications of this model depend on the actual choice of the SUSY breaking A-terms. If the CKM matrix is generated in the down sector (by A^d), Bs->mu^+mu^- receives non-decoupling contributions from Higgs penguins which become important already for moderate values of tan(beta). Also the Bs mixing amplitude can be significantly modified compared to the SM prediction including a potential induction of a new CP-violating phase (which is not possible in the MSSM with MFV).

Nasolabial aesthetics correlates poorly with skeletal symmetry in unilateral cleft lip and palate

To evaluate the correlation between symmetry of the craniofacial skeleton and aesthetics of the nose and upper lip in children with complete unilateral cleft lip and palate (CUCLP).

Nasolabial symmetry and aesthetics in children with complete unilateral cleft lip and palate

The objective of this study was to evaluate the association between nasolabial symmetry and aesthetics in children with complete unilateral cleft lip and palate (CUCLP). Frontal and basal photographs of 60 consecutively treated children with CUCLP (cleft group: 41 boys and 19 girls, mean (SD) age 11 (2) years) and 44 children without clefts (control group: 16 boys and 28 girls, mean (SD) age 11(2) years), were used for evaluation of nasolabial symmetry and aesthetics. Nasal and labial measurements were made to calculate the coefficient of asymmetry (CA). The 5-grade aesthetic index described by Asher-McDade et al. was used to evaluate nasolabial appearance. Correlation and regression analysis were used to identify an association between aesthetics and CA, sex, and the presence of CUCLP. Ten measurements in the cleft, and 2 in the control, group differed significantly between the cleft and non-cleft (or right and left) sides, respectively. The significantly higher values of 9 of 11 CA in the children with CUCLP indicated that they had more asymmetrical nasolabial areas than children without clefts. However, the regression analyses showed that only a few CA were associated with nasolabial aesthetics. In conclusion, nasolabial aesthetics and nasolabial symmetry seem to be only weakly associated in patients with CUCLP.