A third study of football player photographs revealed that the faces of less dominant (smaller) football players were more similar to the canonical smile display than the faces of their physically larger counterparts
In other words, smiling seems to convey information that is not limited to advertising the emotional state of the displayer (e.g., I feel happy) but also appear to generate inferences—in the mind of observers—about the dispositional characteristics of the displayer (e.g., I am friendly and non-threatening), a view that is consistent with facial expression research in the behavioral ecology tradition (Fridlund, 1994; Parkinson, 2003).
