Feeling and showing: A new conceptualization of dispositional teacher enthusiasm and its relation to students' interest

• We modeled dispositional teacher enthusiasm consisting of positive affect and positive emotional expressivity.
• Indicating construct validity, dispositional teacher enthusiasm is found as a predictor for students' perceived enthusiasm.
• Dispositional teacher enthusiasm impacts students' interest, mediated by perceived enthusiasm.

Although teacher enthusiasm is a relevant variable in the teaching context, a clear definition is still lacking. Research on teacher enthusiasm is characterized by ambiguous conceptualizations of enthusiasm as either an affective characteristic of teachers or behaviors of expressiveness. Integrating these two notions, a new conceptualization of dispositional teacher enthusiasm, defined by teachers' positive affect and positive emotional expressivity, was developed. It was hypothesized that dispositional teacher enthusiasm would relate to students' interest, mediated by students' perceived teacher enthusiasm. Based on a correlational study design, secondary teachers (N = 75) from Switzerland reported on their enthusiasm, complemented by student ratings (N = 1523) on perceived enthusiasm and interest. Multilevel structural equation modeling revealed that dispositional teacher enthusiasm positively predicted students' interest, which was fully mediated by students' perceived enthusiasm, providing the basis of a valid definition of teacher enthusiasm. Based on this integrative definition, implications for future research are discussed.