Social Contagion

Social contagion is the term used by psychologists to describe the copycat effect - imitative behavior based on the power of suggestion and word of mouth influence.

Social contagion operates on three levels - the emotional, behavioral and ideational - 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 that spread by suggestion (rumor, urban legends, irrational belief)

Additionally, illness can spread by a combination of the power of suggestion and word of mouth (such as dizziness, headaches, itching, and queasiness - and even serious disorders such as ME, depression and anorexia), and when this happens the term  hysterical contagion is used (because the symptoms often include those associated with clinical hysteria).

For a short summary of research into social contagion, its causes and consequences, see my paper published in the Journal of Memetics, or for a more in depth review, read the research review in my PhD