Smiling Signals Intrinsic Motivation

The nature of a person’s motivation (whether it is intrinsic or extrinsic) is a key predictor of how committed they are to a task, and hence how well they are likely to perform at it. However, it is difficult to reliably communicate and make inferences about such fine nuances regarding another person’s motivation. Building on the social functional view of emotion and the evolutionary and psychophysical characteristics of facial expression of emotions, this research suggests that displayed enjoyment, as evidenced by the size and type of someone’s smile, can serve as a strong nonverbal signal of intrinsic motivation. Taking the perspective of both actors and observers, five studies show that people infer greater intrinsic motivation when they see others display large Duchenne (vs. small) smiles, and that actors intuit this relationship, strategically displaying larger and more Duchenne-like smiles if they have an accessible goal to signal intrinsic (vs. extrinsic or no specific) motivation.