Contagious?

Emotional contagion is the tendency to express and feel emotions that are similar to and influenced by those of others. One view of the underlying mechanism is that it represents a tendency to automatically mimic and synchronize facial expressions, vocalizations, postures, and movements with those of another person and, consequently, to converge emotionally. A broader definition of the phenomenon was suggested by Sigal G. Barsade- "a process in which a person or group influences the emotions or behavior of another person or group through the conscious or unconscious induction of emotion states and behavioral attitudes"



Social contagion is imitative behavior based on the power of suggestion and imitative influence.

Social contagion operates on four levels - emotional, behavioral, ideational, and hysterical - and depending on which level appears to be predominant, psychologists categorize social contagion accordingly:

• emotional contagion - infectious moods and sentiment (aggression, depression)
• behavioral contagion - infectious behavior (ranging from yawning and laughing to crime)
• ideational contagion - infectious ideas spread by suggestion (rumor, urban legends, irrational belief)
• hysterical contagion - somatic illness spread by the power of suggestion (depression/anorexia)

But is that really all there is to it? Do we err fundamentally by ascribing "psychological" rather than "physiological" causes to these modalities of contagious mass behaviour? Where exactly does agency reside within our composite organism? What again, is the optimal unit of selection driving our "species" behaviour?