Anisotropies in visual perception have often been presumed to reflect an evolutionary adaptation to an environment with a particular anisotropy. Here, we adapt observers to globally-atypical environments presented in virtual reality to assess the malleability of this well-known perceptual anisotropy. Results showed that the typical bias in orientation perception was in fact altered as a result of recent experience. Application of Bayesian modeling indicates that these global changes of the recently-viewed environment implicate a Bayesian prior matched to the recently experienced environment. These results suggest that biases in orientation perception are fluid and predictable, and that humans adapt to orientation biases in their visual environment "on the fly" to optimize perceptual encoding of content in the recently-viewed visual world.