A 'socially infectious disease'

From an interesting article in New Scientist (2005):

Witnessing gun violence can double the likelihood of a teenager committing serious violence in the following two years, suggests a study by US researchers.

"There are often social stimuli that are ambiguous - like at a crowded party, someone bumps into you. How do you interpret those stimuli?” he asks. Webster suggests that people exposed to violence may be more prone to assume a hostile intent - as a self-defence mechanism - which could in itself lead to violence.

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