Our bodies appear symmetrical on the outside, but our brains are lop-sided. For example, the brain is better at controlling one hand than the other.
And right-handers prefer to sit to the right at the movies.
By sitting to the right of the screen, the film is predominantly processed by the right-hemisphere and the suggestion is that, without realizing it, right-handers are choosing to sit in an optimal position for their brain to digest the movie.
And see here. We trigger our ‘brain bias’ in other ways too:
This new research comes after a past study showed that adults with a more artistic, less analytic thinking style (associated with the right hemisphere) were more likely to sit on the right-hand side of the classroom; and another that showed people are more likely to exhibit the left side of their face (controlled by the right hemisphere) when asked to express emotion in a family photo, but to show their right profile when asked to pose as a scientist.