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SUMMARY: Deriving a Theory of the Perceived Motion Direction of Plaids - P
 rofessor George Sperling (Department of Cognitive Sciences\, University of
  California\, Irvine)
DTSTART:20190701T120000Z
DTEND:20190701T130000Z
UID:TALK126337@talks.cam.ac.uk
CONTACT:John Mollon
DESCRIPTION:Based on prior work\, we know that at an early stage the visua
 l system has three different systems that independently extract visual mot
 ion information from visual inputs.  At later stages\, these systems combi
 ne their outputs.  Here\, we consider a much studied (>650 publications) c
 lass of visual stimuli\, plaids\, which are combinations of two sine waves
 .  Currently\, there is no quantitative theory to explain the perceived mo
 tion of plaids. With an important methodological improvement\, we obtained
  a large set of data exploring the various dimensions in which same-spatia
 l-frequency plaids differ.  We found that only two of the three motion sys
 tems are active in plaid processing. With this clue\, we were able to form
 ulate a pure theory for the outputs of the first-order and third-order mot
 ion systems and how they combine.   With zero parameters estimated from th
 e data\, the theory captures the essence of the full range of our plaid da
 ta and supports some surprising\, counter-intuitive conjectures about how 
 vision works.\n
LOCATION:Ground Floor Lecture Theatre\, Department of  Psychology
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