Imagine the decisions you might make while playing a simple game like 'matching pennies'. At each play, you and your opponent, say the mathematician John vonNeumann, each lay down a penny heads or tails up. If both pennies show the same side, vonNeumann wins, if not, you win. Before each play, you have the subjective experience of deciding what to do: of choosing whether to play heads or tails. Although decisions like these are not yet understood at a physiological level, progress has been made towards understanding simple decision making in at least one model system: the primate neural architecture that uses visual data and prior knowledge about patterns in the environment to select and execute saccades. Both the visual system and the brainstem circuits that control saccadic eye movements are particularly well understood, making it possible for physiologists to begin to study the connections between these sensory and motor processes at a level of complexity that would be impossible in other less well understood systems.