Immersive mediums replace thought
In an fMRI study, certain films have very high inter-subject correlation of thought patterns (Hasson et al, 2008). This points towards film literally replacing our own internal narrative of thought with its own narrative as we become deeply immersed into the film. A similar effect can be seen across any medium of consumption. When we read we stepping into the author's thoughts or world they have constructed, often leaving our own thought process behind.
The level of immersivity depends both on the medium and the reader. Some may be more engaged with material than others: writing, questioning, taking notes, turning the medium into more of a conversation (Three engagement factors).
In opposition with: Engaging mediums encourage thought
Hasson, U., Landesman, O., Knappmeyer, B., Vallines, I., Rubin, N., & Heeger, D. J. (2008). Neurocinematics: The Neuroscience of Film. Projections, 2(1), 1–26. doi:10.3167/proj.2008.020102