Don Macleod

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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
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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
AND Rods reverse Red/blue polarity (Purkinje
shift)
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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?