The benefits of epistemic action outweigh the costs

Epistemic actions are physical actions people take to simplify internal problem solving rather than to move closer to an external goal. When playing the video game Tetris, for instance, experts routinely rotate falling shapes more than is strictly needed to place the shapes. Maglio and Kirsh (Kirsh & Maglio, 1994; Maglio, 1995) proposed that such actions might serve the purpose of priming memory by external means, reducing the need for internal computation (e.g., by way of mental rotation). This proposal requires that information provided by epistemic actions (e.g., additional views of the shape) serve the same function as memory primes, and that the bene t of such priming exceed the costs of performing the epistemic action. To calculate bene t, we used a novel statistical method for mapping reaction-time data onto an estimate of the increase in individual processing capacity a orded by seeing shapes in multiple orientations. To calculate cost, we used an empirical estimate of time needed to take action in a Tetris game. We found that the bene ts of extra previews far outweigh the costs of taking extra action.