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Libet/Experiment/Frith: (1983): E.g. Raising a finger when one feels the desire to do so. The brain activity was measured with an EEG.
It was already known that there was an activity before the spontaneous movement. (Standby potential). It can take up to one second before lifting.
New: Libet: the people should remember the moment when they felt the desire.
This point of time they could read on a special clock. The experiment was repeated and confirmed with different clocks.
Desire: occurred about 200 msec before actual lifting.
N.B.: the characteristic change in brain activity, the standby potential occurred approximately 500 msec before actual lifting.
Interpretation: does the experiment show that we have no free will?
Problem: the alternatives are extremely trivial.
Freedom of Will/Frith: the experiment does not show that we do not have free will, but that we are not aware of having made the choice at an earlier point of time.
Variant: reacting to a tone with pressing a button. The clock to be observed was a special dial on a computer screen.
N.B.: the "mental" and the physical time did not agree. In your head pressing the button occurs a bit later and the sound of the bell occurs somewhat earlier.
Mental time/Frith: here the components of the action are connected.
Variant: the finger twitch is triggered from the outside by a magnetic pulse. Then you do not feel like you are the originator.
Action: the finger-twitch is no action then. The brain no longer connects the sound and the twitching.
Mental time: is here pulled apart.
N.B.: by doing this, the brain realizes that you are not the originator.
Libet/Experiment/Freedom/Freedom of Will/Will/Frith: the instruction to behave self-determined leads to an illusory freedom.
Instead we play a complex game with the experimenter.
Wie unser Gehirn die Welt erschafft Heidelberg 2013