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Contagious yawning, emotional contagion and empathy are characterized by the activation of similar neurophysiological states or responses in an observed individual and an observer. For example, it is hard to keep one’s mouth closed when imagining someone yawning, or not feeling distressed while observing other individuals perceiving pain. The evolutionary origin of these widespread phenomena is unclear, since a direct benefit is not always apparent. We explore a game theoretical model for the evolution of mind-reading strategies, used to predict and respond to others’ behavior. In particular we explore the evolutionary scenarios favoring simulative strategies, which recruit overlapping neural circuits when performing as well as when observing a specific behavior. We show that these mechanisms are advantageous in complex environments, by allowing an observer to use information about its own behavior to interpret that of others. However, without inhibition of the recruited neural circuits, the observer would perform the corresponding downstream action, rather than produce the appropriate social response. We identify evolutionary trade-offs that could hinder this inhibition, leading to emotional contagion as a by-product of mind-reading. The interaction of this model with kinship is complex. We show that empathy likely evolved in a scenario where kin- and other indirect benefits co-opt strategies originally evolved for mind-reading, and that this model explains observed patterns of emotional contagion with kin or group members.

[Purpose] Recent findings suggest there is an interesting interaction between the stomatognathic system and the musculoskeletal system. The aim of this study was therefore to examine the influence of the temporomandibular joint on the explosive strength of the lower limbs. [Subjects and Methods] An observational study was carried out. The subjects were 60 male football players who voluntarily participated in the investigation. After a warm-up phase of 10 minutes, each participant performed three Squat Jumps (SJ) with different mandible positions: mouth closed and mouth open. SJ heights were recorded using a Sensor Medica force platform and the FreeMed system. [Results] Sixty participants were enrolled in this study (age: 24 ± 7 yrs; height: 174 ± 4.6 cm; weight 63.7 ± 7.6 kg). The SJ heights with the mouth closed, 38.50 ± 4.0 cm, were shorter than those with the mouth open, 40.4 ± 4.1 cm. Statistical analysis showed there was a statistically significant difference between the performances. [Conclusion] This pilot study highlighted that occlusal factors can influence physical performance and this could have practical applications in sports and exercise science. However, our results have to be confirmed in studies with larger numbers of participants and supported by other investigations.

We describe a method for the automatic identification of facial features (eyes, nose, mouth and chin) and the precise localization of their fiducial points (e.g. nose tip, mouth and eye corners) in color images of face foregrounds. The algorithm requires as input 2D color images, representing face foregrounds with homogeneous background; it is scale-independent, it deals with either frontal, rotated (up to 30°) or slightly tilted (up to 10°) faces, and it is robust to different facial expressions, requiring the mouth closed and the eyes opened, and no wearing glasses. The method proceeds with subsequent refinements: first, it identifies the sub images containing each feature, afterwards, it processes the single features separately by a blend of techniques which use both color and shape information. The system has been tested on three databases: the XM2VTS database, the University of Stirling database, and ours, for a total of 1650 images. The obtained results are described quantitatively and discussed.