Much of game theory rests on the foundation of common knowledge: actors sharing common beliefs about one another and about the nature of the game being played. While common knowledge is reflexively invoked, it is rarely realized. Whether actors examine a game, examine one another, and then arrive at a similar set of beliefs remains an open question.
Drawing on concepts from evolutionary psychology, this paper focuses on a social cue that can affect the beliefs held by actors playing a simple game. Our contention is that the image of a player's counterpart contains information that is used by the player in formulating beliefs and subsequent actions. The population of possible players encompasses many different types, whose personal characteristics may be correlated with play and whose image may signal a type.