Libet et al.2 authored a study in the early 1980s that has served as an academic foundation for years of subsequent research into the question of free will. I essentially replicated the experimental design when I asked you to arbitrarily choose an eye to wink.
Findings from Libet’s experiment demonstrated that the conscious experience of having chosen a particular arm to raise occurred nearly 500 milliseconds after neural mechanisms involved in arm raising had already begun the process.2
Haggard and Eimer3 updated this experimental design and showed that the conscious experience of having initiated a voluntary action coincided not with the neural preparation for the action, but instead occurred later during the actual execution of the action. In other words, Haggard and Eimer showed that your brain chose which eye to wink before both your eye winked and before you had the conscious experience of having made a choice between left and right.
I chose not to wink at all. Explain that.