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Unformatted text preview: what is we want to, that our consciousness really comes into view. Thinking
about consciousness in this way suggests that consciousness occurs after the fact, not before. We tend to view it as something we are directing..our movements, what we are saying.. which is all a part of free
will. Maybe we don't really have as much control as we think -- maybe we are reacting in a certain way, and our consciousness is just our interpreter..thus happening after the event. Is there a way to capture that
delay? First done by Libet in his backward-referral hypothesis Neural Correlates of Consciousness!
Volitional Control !
When Do We Become Conscious of Our Thoughts?!
Benjamin Libet! Backward Referral Hypothesis:!
States that our conscious awareness of a neural event is delayed (by
approximately 500 msec), but we refer this awareness back in time so
that we think we are aware of the event from its onset.!
Had subjects sit in front of a timer, and while doing this had EEG electrode on the scalp. There are distinct EEG signals right before making a
movement (a neurological marker). The subject was instructed to move their ﬁnger at any time that they choose, but when they do, right before
they make that movement, to notice the time on the clock. And then compare that to the brain signals w/ that movement, and they found that the
timing of those brain signals happens way before that choice to move. Now when Libet did this, found happened about 1/2 a sec, but other have
found it is even longer than that (10 sec from when the brain begins to prepare to make that movement). Suggest that consciousness is an illusion,
that the brain is already preparing to do all these things, and by the time we decide to, it was already planning hat movement out. Methods:!
- subjects sit in front of a timer with an EEG electrode on their scalp!
- they are instructed to make a ﬁnger movement at any time of their choosing!
- further, they are asked to note the time when they ﬁrst had the urge to move!
- the timing of the evoked potential was compared...
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- Fall '11