Transcript Consciousness - UCSD Cognitive Science

Consciousness
Side dish or the whole shebang?
Sean Davis  Erin Hecht  Kris Tew  Lydia Wood
COGS 175  Spring 2005
Erin
• Definitions
• Philosophy & evolution
Lydia
• Motor commands & social theory
Kris
• Quantum physics & determinism
Sean
• Meditation & “The Prime Mover”
Introduction to the Debate About
Consciousness
Definitions, Philosophy and Evolution
Erin Hecht
Definitions
• Consciousness
• Awareness; free will; qualia
• Epiphenomenon
• Dictionary: “A secondary phenomenon that
results from and accompanies another”
• Conscious epiphenomenalism: “Mental states
are produced by physical states but have no
causal role to play”
– Blackmore 2004
• Physical  Mental but NOT Mental  Physical
Definitions
• Causal
• Mental  Physical
• The causal paradox: “Viewed from a firstperson perspective, consciousness appears to
be necessary for most forms of complex or
novel processing. But viewed from a thirdperson perspective, consciousness does not
appear to be necessary for any form of
processing”
- Max Velmans, quoted in Blackmore 2004
A thought experiment
• Chalmers’s zombies
• Humans without consciousness
• “The hard problem”
• Why do we exist instead of zombies?
• Dennet’s zimboes
• Zombies with recursive loops
Three ways to approach the
evolution of consciousness
1.
Epiphenomenalism or conscious
inessentialism
• Zombies are possible
• Consciousness is separable from
intelligence, memory, language, etc. &
adding it to these abilities makes no
difference in behavior of the organism.
• The question: So how did we evolve?
Three ways to approach the
evolution of consciousness
2.
Consciousness serves an
evolutionary function
• Zombies are not possible
• Consciousness is separate from other
functions, but adding it makes a difference
• The question: What is its evolutionary
purpose?
Three ways to approach the
evolution of consciousness
3.
Functionalism
• Zombies are not possible
• Not separable from other functions; a
conscious creature is a package deal (or
consciousness = emergent property)
• The question: How do these other functions
give rise to consciousness?
Consciousness as a Causal
Phenomenon
•Voluntary Motor Control
•Impact of Social Cognition
Lydia Wood
Libet’s Argument
• Motor plan initiation indicated by
presence of Readiness Potential (RP)
• RP found over central sensorimotor
area (Cz)  slow negativity
preceding a movement
• RP occurs ~500 ms before voluntary
movement, self-reported decision to
move occurs only ~200 ms before
movement
Libet et al. (1983)
Therefore…
• The person becomes aware of the
decision to move only after the motor
plan has been initiated
• Conscious decisions do not have a
causal relationship with voluntary
motor control
• Are voluntary movements voluntary?
Problems With Libet’s Methods
• Used average time of reported
consciousness, instead of earliest
time
• Smearing effect produces skewed EEG
avgs
• RP more likely to reflect general
readiness prior to an action than
specific command to execute a
particular action
• Lateralized Readiness Potential (LRP)
Trevarna and Miller (2002)
Trevana and Miller’s Results
• Earliest decisions to move still
occurred after onset of RP
• 20% of people reported decision to
move prior to mean LRP onset
• Consciousness may play a causal
role in the execution of an action
Trevarna and Miller (2002)
Social Self-Awareness
• Three parts of self-awareness
• Sense of continuity
• Sense of personal agency
• Sense of identity
• Self-awareness allows for
introspectively based social
strategies for competing and
cooperating
Gallup (1998)
What Can You Do With Consciousness?
• Make mental object of self and other
• Simulate counterfactual mental
states based on previous experience
(pretending)
• Infer other mental states (empathy)
• Modify behavior to take advantage of
other mental states (deception)
Back to Zimbos
Say there is a computer…
• With subroutines that monitor operation
of specific features
• That then uses this information to make
inferences about similar systems in
other computers
• And then modifies its own processing
performance to gain competitive edge
Gallup (1998)
Internal States and Determinism
Heisenberg’s Uncertainty Principle and the
Double Slit
Kris Tew
Materialism to Determinism
• Early 19th - 20th Century Materialism states only material things
exist whose behavior is totally defined by the laws of physics.
• Theoretically if you knew the position and momentum of all
matter within a system everything done within that system could
be predicted.
• The human brain is composed of matter, the behavior of the
brain is, in theory, predictable.
• Problem: If only material things exist, either internal states like
understanding must not exist or they must have a material
component.
Heisenberg's Uncertainty Principle
• It is not possible to know the exact
position and momentum of matter.
• The more precisely the position is
determined the less precisely the
momentum is known.
The Double Slit Experiment
• Waves and the Interference Pattern
• A single electron causes an interference
pattern as if it was a wave
Inherent Randomness
• Path selection and monitoring
• Interference pattern vanishes
• Waves to Bullets
• Random selection
Heisenberg, Consciousness and Uncertainty
• Monitoring the slits
• Unpredictable change within a system
• Internal states can exist within a
material system because of uncertainty.
Consciousness as a Causal
Phenomenon
-Meditation Causes Physiological Changes
-Consciousness is the Prime Mover
Sean Davis
Meditation
• Compassion meditation is a purely
internal phenomenon
• Meditation causes physiological
changes
• Perhaps physical states and mental
states are the same
The Prime Mover
• The stick hits the ball… the hand
moves the stick… the arm moves the
hand... where does it start?
• Consciousness is the originator, or
prime mover
Cognition is Distributed
• Expectation and environment are the
two major influences of a
psychadelic experience
• Maybe cognition exists outside the
body
Thought Provoking Questions
• Is consciousness epiphenomenal or
causal?
• What does it mean to have free will?
How does it relate to determinism?
• Are zimbos conscious? Zombies?
Can they exist?
• Is consciousness something that is
individual, or socially distributed?
More questions
• Fast or slow?
• Tattersall: “any novelty has to arise
spontaneously as an exaptation, a structure
existing independently of any new function for
which it might later be co-opted,” so
consciousness arose “abruptly, as the byproduct of something else”
• Genetic or memetic?
• Dennet: memeplex and selfplex; parallel
processor with a serial virus (“the Joycean
machine”)
• Jaynes: Greeks and the bicameral mind
References
Blackmore, Susan. (2004) Consciousness. Oxford University Press.
Gallup, G. G. (1998). Self-awareness and the evolution of social intelligence.
Behavioral Processes. 42, 239-247.
Libet, B., Gleason, C. A., Wright, E. W., & Pearl, D. K. (1983). Time of conscious
intention to act in relation to onset of cerebral activity (ReadinessPotential): The unconscious initiation of a freely voluntary act. Brain. 106,
623-642.
Tattersall, Ian. (2004) What Happened in the Origin of Human
Consciousness? The Anatomical Record (Part B: New Anat.) 276B: 19-26.
Trevarna, J. A. & Miller, J. (2002). Cortical movement preparation before and
after a conscious decision to move. Consciousness and Cognition. 11,
162-190.
Wright, Robert. (1994) The Moral Animal. Vintage Books.
Lutz, A. et al., (2004) Long-term meditators self-induce high-amplitude gamma
synchrony during mental practice. PNAS, 101: 16369-16373
Newberg, A.B. and Iversen, J. (2003) The neural basis of the complex mental
task of meditation: neurotransmitter and neurochemical considerations.
Medical Hypotheses, 61(2): 282-291