Beheading has been discontinued as a form of execution in much of the world due to the suspicion that a severed head remains conscious and able to experience pain, so there have been no recent scientific observations of human decapitation. However studies of decapitated animals has lent some credibility to the massive number of stories regarding a head's brief consciousness after being separated from the body. Under certain circumstances, it is very possible that a head so removed may remain lucid long enough to know its fate.
In many cases, the anecdotal evidence describes blinking eyes, wandering gaze, and moving lips on a freshly amputated head. As grotesque and troubling as these movements may be to the witnesses, such muscular spasms are not surprising under the circumstances. It is not uncommon for any separated limb to twitch briefly due to reflex nerve action. More difficult to attribute to nerve reflexes are the stories of specific facial expressions sometimes seen on the faces of the beheaded as they died. Some were said to change expressions several times in the last few moments, ranging from pain and confusion to grief and fear.
In the heyday of the guillotine during the French Revolution, it is said that many of the condemned were asked to blink for as long as possible after decapitation. While many reportedly did not blink at all, some complied for as long as thirty seconds. Still other observations describe much more specific reactions to stimuli following beheading. Consider the case of Languille, a convicted murderer who was guillotined in France. He was observed by Dr. Beaurieux during his execution at 5:30am on June 28th, 1905. As written in Archives d'Anthropologie Criminelle, here are the doctor's observations:
I have just recounted to you with rigorous exactness what I was able to observe. The whole thing had lasted twenty-five to thirty seconds.
In the book Crucibles: The Story of Chemistry, a story is related where the unnamed servant of chemist Antoine Lavoisier was beheaded by guillotine. According to the writer, Lavoisier immediately picked up the head and asked the servant to blink if he understood. Reportedly, the man blinked. There is also an oft-repeated anecdote involving Antoine Lavoisier's own later experience on the guillotine in 1794. The story is dubious considering that it does not appear in any of his biographies, but reportedly he told his assistant that he would blink for as long as he was able after execution, and successfully did so for fifteen to twenty seconds.
A more recent account tells of an accidental decapitation in an automobile. In 1989, a U.S. Army veteran who served in the Korean war was riding in a taxi with a friend when it collided with a truck. The witness was pinned to his seat, and the friend was decapitated by the collision:
Can it be concluded that a separated head is capable of consciousness and awareness following the event? Not with any certainty. Further scientific observation of human decapitation is highly unlikely, so it is a question that may remain unanswered indefinitely. But there is much evidence to indicate that for some, death is not instantaneous, which probably offers a truly surreal experience for those few, brief moments. It goes without saying that there are no first-hand accounts to shed further light on the subject.