Proprioceptive alphas are able to take advantage of the human "blind spot". Because human beings have two eyes, the optic nerve has to translate two sets of data into a single, three-dimension image. The spacing of our eyes allows for a gap in this data. Griffin's Alpha ability affects other people's optic nerves, expanding the blind spot to accommodate their size.
This type of alpha has been noted as antisocial, they don't appear to like being watched.