Diefendorff, J.M., Richard, E.M., & Croyle, M.H.
Journal of Occupational and Organizational Psychology Vol. 90 Issue 6, pp. 1256-1264.

This study explored whether emotional display rules are perceived by part-time employees and their supervisors as formal job requirements. Results showed that display-related behaviors were thought to be required activities (i.e., in-role) by the majority of the sample, and employees and supervisors generally agreed in this perception. Job-based differences in interpersonal requirements predicted the extent to which employees and supervisors categorized display-related behaviors as required, with more interpersonal requirements being associated with greater in-role categorization. Job-based differences in interpersonal requirements also predicted the level of agreement between employees and supervisors in categorizing display-related behaviors as in-role or extra-role. Finally, job satisfaction and job involvement predicted the extent to which employees categorized emotional display behaviors as being required in their jobs, with more satisfied and more involved individuals rating emotional display behaviors as in-role at a higher rate than less satisfied and less involved individuals