“Emotions, Like Germs, Are Easily Transmissible. The Trick Is Passing and Receiving the Right Ones” (Washington Post). Emotional contagion occurs in milliseconds, entirely beyond our awareness. We unconsciously mimic the facial expressions, posture and gestures — body language — to which we are exposed; the phenomenon can be gauged experimentally by measuring the tone of the muscles of facial expression, for example. Incremental changes in these muscles may help trigger the associated emotion in the bearer. Modulation of speech tone is also matched and mimicked. Of course, some people are better than others at infecting those around them with their moods, and others are more sensitive to people’s emotions. The article does not mention the mirror neuron concept, one of the darling new paradigms of neuropsychology (which I have followed and written about here for several years), which almost certainly underlies and shapes this emotional contagion. It makes sense that a mechanism for emotional contagion developed, given the adaptive value of the role it plays in social cohesion. This also bears a relationship to why it is largely unconscious and automatic, and why it operates most strongly in our most intimate social contexts. That does not mean, of course, that those aware of the infectious nature of their moods cannot attempt to exercise some control. (However, beware the new light this casts on Machiavelli’s dictum that, if you cannot both be loved and feared, it is better to be feared than loved.)