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Don Macleod

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hearts flutter. Previous theories. Helmholtz 1867: blue cones more sluggish than red ... Red/blue polarity (Purkinje shift) Our theory: You see each heart ... – PowerPoint PPT presentation

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Title: Don Macleod


1
Why hearts flutter
  • Don Macleod Stuart Anstis

Don Macleod
Stuart Anstis
UCSD
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Previous theories
Wrong
  • Helmholtz 1867 blue cones more sluggish than red
  • Von Kries 1896 rods more sluggish than cones
  • 1975 lateral inhibition at borders
  • 2003 equiluminous motion is slow

Wrong
Wrong
4
Previous theories
Wrong
  • Helmholtz 1867 blue cones more sluggish than red
  • Von Kries 1896 rods more sluggish than cones
  • 1975 lateral inhibition at borders
  • 2003 equiluminous motion is slow


Wrong
Wrong
AND Rods reverse Red/blue polarity (Purkinje
shift)
5
Our theory
LIGHT HEART
  • You see each heart TWICE--
  • First with the cones
  • Then with the more sluggish rods.
  • Brightness REVERSES, because rods
  • are 20x more sensitive to blue than to red
    (Purkinje shift)

DARK HEART
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SIMULATION
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Our theory explains 1. Flutter, and predicts
two NEW illusions
  • 2. Light or Dark Ghostly twins (50 ms delay)
  • 3. Reversed red-blue motion
  • which I shall now fake simulate

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SIMULATED MOTION REVERSAL
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Blue luminance --gt
Red luminance --gt
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Blue luminance --gt
lt-- 20x --gt(1.3 l.u.)
RB (rods)
Red luminance --gt
RB (cones)
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Blue luminance --gt
lt-- 20x --gt(1.3 l.u.)
RB (rods)
Red luminance --gt
DATA
RB (cones)
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Data!
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CONCLUSIONS All three illusions
  • Flutter
  • Ghostly twins
  • Reversed motion

Occur when R gt B for cones R
lt B for rods
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So we can explain one old illusion and two new
ones
  • Flutter
  • Ghostly twins
  • Motion reversal

with two old mechanisms 1. Rods are sluggish
(50 ms) 2. Rods reverse R/B luminance polarity,
giving a positive superimposed on its own
negative.
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  • Any questions?
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