Key points are not available for this paper at this time.
1 Neurosensory Center and Departments of Neurology and Psychology, University of Iowa, Iowa City, Iowa. This investigation was supported by Research Grant NB-00616 and Program-Project Grant NB-03354 from the National Institute of Neurological Diseases and Blindness, USPHS.
Benton et al. (Sat,) studied this question.