Boundary correlators provide insight into the emergence of an effective geometry in higher spin gravity duals of O(N) or U(N) symmetric field theories. After a brief introduction into higher spin holography, I will discuss recent progress on the understanding of the large N phase transitions that can occur even in free boundary models. While the low-temperature behavior of thermal two-point functions is consistent with a bulk thermal AdS space, we observe a significant departure at large temperatures, consistent with the appearance of localized black hole like objects. In adjoint models, these objects appear at length scales of order of the AdS radius, consistent with a Hawking-Page transition, but in vector models they are parametrically larger than the AdS scale.
