A presentation given as part of my thesis on Free Will while at University of Cambridge. Exploring the concepts of Free Will, Consciousness and Movement from a Computational and Neuroscience perspective. Exploring Brain Veto, and if move before we think based on Benjamin Libet's early work alongside the work of Donald Hoffman and the real reason for brains (also heavily influenced by the work of Neuroscience and Engineer Daniel Wolpert.

1. Unconscious cerebral initiative and the
role of conscious will in voluntary action
Benjamin Libet
THE BEHAVIORAL AND BRAIN
SCIENCES (1985) 8, 529-566

2. Introduction
• A role for "the unconscious" in modifying and controlling volitional
decisions and actions was advocated long ago (e.g., Freud 1955;
Whyte 1960).
• In the 1980’s Neuroscientist Benjamin Libet ran a series of
experiments to explore and compare:
– the time of the onset of conscious intention to act and the
time of onset of associated cerebral processes.
– does conscious intention or decision to act actually initiate a
voluntary event.
– should subjective experience of this intention precede or at
least coincide with the onset of the specific cerebral processes
that mediate the act.

3. Test yourself. Don’t try this at home!

4. How did the scientists test their theory?
• 5 subjects were wired up to EMG. Scalp
and wrist/finger.
• Measured the response time in the
appropriate muscle (finger and wrist of
the right hand). 40 trials.
• For each trial, subjects were asked to
perform a simple quick flexion of the
wrist or fingers at any time they felt the
"urge" or desire to do so.
• The subject was then asked to note the
position of the moving dot when he/she
was aware of the conscious decision to
move a finger or wrist by pointing.

5. How did the scientists test their theory?
• Important: They were also free NOT to act out
any given urge or initial decision to act.
• Each subject reported frequent experiences of
aborted attempts.

6. Key terms explained
• ‘Voluntary Action’ and ‘will’
• “an act is regarded as voluntary and a
function of the subject's will when:
– (a) it arises internally and not in direct
response to an external stimulus or cue;
– (b) there are no externally imposed
restrictions or compulsions that directly or
immediately control subjects initiation and
performance of the act.
– (c) subjects feel introspectively that they are
performing the act on their own initiative and
that they are free to start or not to start the
act as they wish.”

7. Key terms explained
• RPs "readiness potentials"
• Voluntary acts are preceded by
electrophysiological "readiness potentials"
(RPs).
• An RP is a scalp-recorded slow negative shift
in electrical potential that is generated by the
brain and beginning up to a second or more
before a self-paced, apparently voluntary motor
act.
– With spontaneous acts involving no
preplanning, the main negative RP shift begins
at about -550 ms.

8. What did Libet learn?
• General evidence suggested that brain activity
initiated the movement hundreds of milli seconds
before the conscious decision was reported.

9. What did Libet learn? EMG Traces

10. Summary tables

11. Other key learnings
• Due to these findings it was suggested free
will might not exist.
• The brain maybe able to consciously veto an
action that has already started in the brain.
• The role of conscious will, would be not to
initiate a specific voluntary act but rather to
select and control an intentional outcome.
• Subjects do not judge the onset of an mental
event such as conscious intention the same
way they judge the onset of an experience
induced externally by a skin stimulus.

12. Brain Veto
• Subjects in the study of RPs and conscious
timings reported that during some of the
trials a recallable conscious urge to act
appeared but was "aborted" or some how
suppressed before any actual movement
occurred.
• There is no technique available for
recording and analyzing any RPs that may
be associated with such spontaneous,
irregularly appearing conscious urges to
act that do not lead to an actual motor
event.

13. Major criticisms of the approach
• Reliant on individual response. Timing is subjective.
– e.g. Repeated testing may lead to boredom, causing
an automatic response rather than a conscious one.
• The subject’s voluntary choice of when to act may
have been influenced by an external requirement.
– Such acts have features that may compromise the
exercise of free volition or confuse its interpretation.
• Is the RP a valid indicator of voluntary acts.
– Recording an RP requires averaging many events.
• The kinds of deliberative and evaluative processes
that are important for free will involve longer time
periods than those studied by Benjamin Libet.
• Could Libets findings be applied to more complex
conscious decisions based on reasons, such as free reject
his hypothesis!

14. Summary & Conclusion
We move before we think.

15. Summary & Conclusion
• The present experimental findings provide direct
evidence that unconscious processes can and do initiate
voluntary action and point to a definable cerebral basis
for this unconscious function.
• The brain "decides" to initiate or, at least, to prepare to
initiate the voluntary act before there is any reportable
subjective awareness that such a decision has taken
place.
• The brain has the ability to veto an action that has
already started.
• Statistical and mathematical evaluation of the
experimental data supported the view that each of us
move before we have conscious urge to.
• The freedom of the subject to act at the time of his
choosing actually provides the crucial element in this
study.
• That Libet’s study was heavily critiqued.

16. Impact
• Libet’s experiments and measurements of the time
before a subject is aware of self-initiated actions
have had a enormous, mostly negative, impact on
the case for human free will.
• Building on the essence of Libet’s findings. Donald
Hoffman’s work has further explored the relationship
between the brain and conscious experience.
• And Daniel Wolpert’s work has reflected and built
upon some of Libet’s findings. For example
suggesting that the only reason we have a brain is to
guide adaptable and complex movements. And that
movement is the only way we have of affecting the
world around us.