The frame of reference for reading rotated text J. Stephen Mansfield and Gordon E. Legge Department of Psychology, University of Minnesota, Minneapolis, MN 55455. Such viewpoint invariance could be attributed to orientation-independent letter recognition. We have explored a new explanation for the dependence of reading on letter and word orientation.
Letters have the same size and orientation, and sit on the smae baseline.
The visual span is the number of letters that can be recognized in a single glance. The visual span for reading is 10 to 15 letters. We hypothesize that parallel processing of the letters in the visual span exploits the spatial structure found in normal text. Knowing the orientation and size and size of previous letters reduces the uncertainty in those attributes for subsequent letters. We refer to this process as binding .