Anisotropy and polarization of space: evidence from naïve optics and phenomenological psychophysics. 
Additional evidence is presented concerning the anisotropy between vertical and horizontal encoding, which emerges from studies of human perception and cognition of space in plane mirror reflections.  Moreover, it is suggested that the non-metric characteristic of polarization - that Jeffery et al.  discuss with respect to gravity - is not limited to the vertical dimension.