Humans tradeoff information seeking and randomness in explore-exploit decisions

The explore-exploit dilemma occurs when we must choose between exploring options that yield information (potentially useful for the future) and exploiting options that yield known reward (certain to be useful right now). We have previously shown that humans use two distinct strategies for resolving this dilemma: the optimal-but-complex ‘directed exploration‘ in which choices are biased towards information, and the suboptimal-but-simple ‘random exploration’ in which choice variability leads to exploration by chance. Here we ask how these two strategies interact. We find that humans exhibit a tradeoff between these two forms of exploration, with higher levels of directed exploration associated with lower random exploration and vice versa. This directed-random tradeoff is described remarkably well by a parameter-free optimal theory that accurately captures individual differences between participants, as well as adjustments by individuals in response to simple experimental manipulations. These results show that humans combine information seeking and randomness in a rational way to solve the explore-exploit dilemma.