How do people play against Nash opponents in games which have a mixed strategy equilibrium?

We examine experimentally how humans behave when they, unbeknownst to them, play against a computer which implements its part of a mixed strategy Nash equilibrium. We consider two games, one zero-sum and another unprofitable with a pure minimax strategy. A minority of subjects' play was consistent with their Nash equilibrium strategy. But a larger percentage of subjects' play was more consistent with different models of play: equal-probable play for the zero-sum game, and the minimax strategy in the non-profitable game.