psy·cho·phys·ics 
(sī′kō-fĭzĭks)
(sī′kō-fĭzĭks)n. (used with a sing. verb)
The branch of psychology that deals with the relationships between physical stimuli and sensory response.
psy′cho·physi·cal adj.
psy′cho·physi·cal·ly adv.
psy′cho·physi·cist (-fĭzĭ-sĭst) n.