Lecture 14: Bistable perception

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Lecture 14 Bi-stable perception Recent studies
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Paper (5-10 pages or 2000 - 4000
words) Introduction phenomenon, background
information, significance Methods
(optional) who are the observers? what
material was used? how was the stimuli (images,
etc) constructed Results Figures/plots,
Descriptions, statistics. Discussion and
Conclusion Interpretation of the results
(observation) Alternative explanations? What
are the implications? Potential
extensions Concluding remarks References
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Ideas New observations or Closer examination of
the illusions we have demonstrated in
class Visual field difference? Gender
difference? Cultural difference? Investigate
the effect of stimulus conditions (e.g.,
contrast?) Context effect? Priming effect?
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Binocular rivalry What is rivaling during
binocular rivalry? eye or feature
suppression? (Blake et al Logothetis
Chen) Bi-stable stimuli and ambiguous
figures Synergies within and between
senses? Kinetic depth reversal (Blake et
al) Feedback information in the brain Diamond
illusion (Murray et al)
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Binocular rivalry
Left eye vs. right eye? Face vs. house?
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Perception, 1980 9(2) 223-31 What is suppressed
during binocular rivalry? Blake R, Westendorf DH,
Overton R. To answer the question 'what is
suppressed during binocular rivalry?" a series of
three experiments was performed. In the first
experiment observers viewed binocular rivalry
between orthogonally oriented patterns. When the
dominant and suppressed patterns were
interchanged between the eyes observers continued
seeing with the dominant eye, indicating that an
eye, not a pattern, is suppressed during rivalry.
In a second experiment it was found that a
suppressed eye was able to contribute to
stereopsis. A third experiment demonstrated that
the predominance of an eye could be influenced by
prior adaptation of the other eye, indicating
that binocular mechanisms participate in the
rivalry process.
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Synergy?
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Synergy?
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Synergy?
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Chicken or duck?
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Murray et al (2002) observed increases in
activity in the shape-processing area -- lateral
occipital complex and decreases in activity in
primary visual cortex when subjects were
perceiving features grouped into shapes (line
drawings, structure-from-motion, diamond). An
example is shown below on a "flattened" cortex.
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