Seeing others yawn selectively enhances vigilance: an eye-tracking study of snake detection.

While the origin of yawning appears to be physiologic, yawns may also hold a derived communicative function in social species. In particular, the arousal reduction hypothesis states that yawning signals to others that the actor is experiencing a down regulation of arousal and vigilance. If true, seeing another individual yawn might enhance the vigilance of observers to compensate for the reduced mental processing of the yawner. This was tested in humans by assessing how exposure to yawning stimuli alters performance on visual search tasks for detecting snakes (a threatening stimulus) and frogs (a neutral stimulus). In a repeated-measures design, 38 participants completed these tasks separately after viewing yawning and control videos. Eye-tracking was used to measure detection latency and distractor fixation frequency. Replicating previous evolutionary-based research, snakes were detected more rapidly than frogs across trials. Moreover, consistent with the view that yawning holds a distinct signaling function, there were significant interactions for both detection latency and distractor fixation frequency showing that vigilance was selectively enhanced following exposure to yawns. That is, after viewing videos of other people yawning, participants detected snakes more rapidly and were less likely to fixate on distractor frogs during trials. These findings provide the first experimental evidence for a social function to yawning in any species, and imply the presence of a previously unidentified psychological adaptation for preserving group vigilance.

FOXO3-NF-κB RelA Protein Complexes Reduce Proinflammatory Cell Signaling and Function.

Tumor-associated myeloid cells, including dendritic cells (DCs) and macrophages, are immune suppressive. This study demonstrates a novel mechanism involving FOXO3 and NF-κB RelA that controls myeloid cell signaling and impacts their immune-suppressive nature. We find that FOXO3 binds NF-κB RelA in the cytosol, impacting both proteins by preventing FOXO3 degradation and preventing NF-κB RelA nuclear translocation. The location of protein-protein interaction was determined to be near the FOXO3 transactivation domain. In turn, NF-κB RelA activation was restored upon deletion of the same sequence in FOXO3 containing the DNA binding domain. We have identified for the first time, to our knowledge, a direct protein-protein interaction between FOXO3 and NF-κB RelA in tumor-associated DCs. These detailed biochemical interactions provide the foundation for future studies to use the FOXO3-NF-κB RelA interaction as a target to enhance tumor-associated DC function to support or enhance antitumor immunity.