Information from the Framingham study showed earlier that happiness can spread from person to person.

VOA: special.2009.12.22

The study is described as the first to demonstrate the indirect spread of happiness.

VOA: special.2009.01.21

Socially conscious hip-hop artists spread messages of peace, security,unity, forgiveness and happiness.

VOA: special.2009.11.25

Sadness also spread among friends, but not as much as happiness.

VOA: special.2009.01.21