Research shows that hose that smile frequently get 10% higher salary. Smiling is used as an indicator of psychological well-being. Smiles induce reciprocity, pro-social behaviour, and altruism. Smiling can also signal trust, cooperation, and social capital among anonymous actors. Given these results, this presentation argues that respondents' frequency of smiling and laughing is rightly included in the PEN survey questionnaire.
Presentation at: ‘PEN: The Long Walk to Impact’, 4th PEN workshop, Barcelona, 8-12 January 2008, 13 pp.