How Explanations Evolve: Social Learning and the Explore–Exploit Trade-off

Explanations are often social objects, and when people try to explain something, they usually have on hand the explanations that others have tried before. We present a simple theory of how people use the explanations they encounter as clues to the broader landscape of possible explanations, which informs decisions to either exploit what has already been done or, conversely, to strike out and explore new possibilities. The challenge of coming up with novel explanations draws people to exploit or imitate appealing ones they have already encountered; this draw increases as less appealing alternatives become more distant (the "strawman" effect). Conversely, when presented with distinct, high-quality explanations, people can merge them, recombining the appealing features in new ways. We test and confirm these predictions using a two-stage transmission chain experiment. In Stage One, 101 participants were asked to explain an unusual scenario. In Stage Two, a separate group of 983 participants were asked to explain the same scenario after reading pairs of explanations drawn from Stage One. We found that participants in Stage Two were more likely to exploit or copy explanations when at least one was high in quality and particularly when it was paired with a weaker alternative. In contrast, participants were more likely to explore or deviate from prior explanations when the two explanations were both high-quality and conceptually distinct. Our work provides new insight into how collective exploration can be promoted, or stalled, by implicit information about what is yet to be discovered.