If you're interested in how this works from a behavioral standpoint, this is a very interesting study: http://digital.library.unt.edu/ark:/67531/metadc5130/m2/

If you're interested in how this works from a behavioral standpoint, this is a very interesting study: http://digital.library.unt.edu/ark:/67531/metadc5130/m2/1/high_res_d/dissertation.pdf http://digital.library.unt.edu/ark:/67531/metadc5130/m2/1/hi...