We can quickly tell whether (and in what direction) a stack of precarious objects will fall. But studying "intuitive physics" in this way requires asking observers about physics in the first place. Here we asked how such physical relationships are (implicitly) encoded into memory. We used a deceptively simple block reconstruction task: observers briefly viewed randomly generated block towers, then rebuilt them from memory, all without ever being told anything about stability or physics. When we later simulated the influence of gravity on both the original and reconstructed towers, we discovered a surprising bias: observers remembered unstable towers as more stable than they initially were, even when their reconstructions were otherwise quite accurate. This suggests that visual memory represents not only what objects are present and where they are, but also how they physically relate to one another.



