Beyond the Smile

With the expectation that innovation, insight, and discovery will come from researching neglected topics, this chapter explores human instincts, including yawning, laughing, vocal crying, emotional tearing, coughing, nausea and vomiting, itching and scratching, and changes in scleral color. The critical change approach is exploited to analyze recently evolved, uniquely human traits (e.g., human-type laughter and speech, emotional tearing, scleral color cues) and compare them with thir primate antecendents, seeking the specific neurological, glandular, and muscular processes responsible for their genesis. Particular attention is paid to contagious behaviors, with the anticipation that they may reveal the roots of sociality and empathy. Few of these curious behaviors are traditionally considered in the context of facial expression or emotion, but they deserve recognition for what they can contribute to behavioral neuroscience and social biology.