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Excerpts from Conversation on Consciousness (by Susan
Blackmore)
“Consciousness is a real working theatre”
Studies Psychology at UCLA
Rejected behaviorism
Psycholinguistics Cognitive Neuroscience
Global Workspace Theory
Bernard Baars
Mind-body paradox
How can we explain how our mental states are related to our physical states when our bodiesare physical and our minds are non-physical?
How to ask questions?Pose questions in a way that’s answerableTreat Consciousness as a variable “What is the difference between two identical
pieces of knowledge, one of which is conscious, and the other one is unconscious?”
The Consciousness “Problem”
Placed an image of a monkey’s face in the left eye Placed the image of a sunburst in the right eye
Binocular Rivalry!
You cannot see both images at the same timeOne image is conscious, the other is unconsciousWe can now compare the representationsAllows us to ask testable questions
William James (1890) and Binocular Rivalry
“When the eyes are presented with images that are
sufficiently different from each other, an interesting thing happens: Rather than fusing the two images into a combined conscious percept, what transpires is a pattern of perceptual alternations where one image dominates awareness while the other is suppressed; dominance alternates between the two images, typically every few seconds.”
3D Glasses?
“Now we know what the neurons are doing in the visual cortex; we know, apparently, at what point the
neurons seem to recognize conscious events, and unconscious events.”
-Bernard Baars
Brain regions for object recognition = where contents of
consciousness emerge The staircase metaphor
Pathway from eyes to visual cortex Below visual cortex: pathway does not have consciousness The visual cortex is like a staircase
As you “climb the staircase” you add more analysis of the visual information
Object recognition is the top of the staircase at the end of the lower temporal cortex
Consciousness occurs at the top of this staircase
Consciousness and Object Recognition
How is it that neurons firing in one part of the brain
cause consciousness, while similar neurons firing in a similar way in another area of the brain doesn’t?
Still lots of gaps in our understanding (still in a primitive stage)
We know a number of basic phenomena
We have useful analogies but they still need to be improved
Explanatory Gaps(Problems with this Theory)
The "inner domain in which we can rehearse telephone numbers to
ourselves [...]. It is usually thought to include inner speech and visual imagery." (in Baars, 1997).
The theatre metaphorConsciousness is a theatre Spotlight of selective attentionWhatever is in the spotlight is the contents of
consciousness In the dark areas of the theatre are the director, stage
hands, etc.These shape what happens in the spotlight but aren’t
apparent themselves
Global Workspace Theory and the “Working Theatre”
Dan Dennett (in Consciousness Explained) : most people
believe there is a place in the brain where “everything comes together” and creates consciousness.
When this “coming together” occurs, events become conscious/apparent to a “viewer” (YOU!)
This theory is tempting, but FALSEYou don’t have to have a theatre metaphor with a little
self in the audienceNo “coming together” in the brain is necessary, the
brain has more sophisticated ways of representing information
Still a useful analogy
Criticisms for Theatre Analogies
Roger Sperry and Michael Gazzaniga Split brain: a brain where the corpus callosum connecting
the two hemispheres of the brain is severed (The two hemispheres cannot communicate)
In the study: both hemispheres were able to answer questions, report perceptual experiences unique to that hemisphere, control the opposite side of the body
Both hemispheres meet criteria for consciousness…
Multiple Consciousnesses?
The Split Brain and Multiple Consciousnesses
• So do we all have multiple consciousnesses?
• Billions of signals pass between the two hemispheres in a normal brain
• Edelman’s dynamic core hypothesis: these signals cause the areas on either side of the brain to work together
• So no… no multiple consciousnesses
This is just a hypothesis! Could be false.
One person with multiple personalities/identities
Unaware/dissociated from each other
Personalities have unique ages/backgrounds/appearances/memories/beliefs/etc…
Multiple Personality Disorder/ Dissociative Personality Disorder
According to the Upanishads: four states of consciousness sleeping, dreaming, waking AND “pure consciousness”
Pure consciousness: consciousness without contentBernard suggests an experiment to find pure consciousness Have subjects listen to noisy air conditioner and report gaps in
the experience of external sound while meditating Dilemma: Gaps may be attributed to falling asleep Having subjects wear a EEG cap would show definitively if they
were falling asleep and would solve this dilemma Dilemma: People may report falsely Testers could use artificial gaps in the noise to solve this dilemma
Meditation and the Fourth State of Consiousness
Excerpts from Conversation on Consciousness, by Susan
Blackmore, found in Minds and Brains (Pages 211-223) http://visionlab.harvard.edu/Members/Olivia/tutorialsDe
mos/Binocular%20Rivalry%20Tutorial.pdf http://www.3dglassesonline.com/learn/how-do-3d-
glasses-work http://www.swamij.com/levelsdimensions.htm http://www.scholarpedia.org/article/Binocular_rivalry https://www.psychologytoday.com/conditions/dissociativ
e-identity-disorder-multiple-personality-disorder
Bibliography