I’ve been meaning to write this one up for years. Do severed heads retain any conscious awareness prior to brain-death? After more research, on and off over years, than I’ve done for any other article, I still can’t be truly definitive. The balance of the evidence suggests some level of consciousness for a few seconds, which inevitably raises for many the horrifying possibility that for a couple of seconds at least, you would be fully aware of the traumatic amputation of your entire body, and perhaps even be able to see it. Nice.
Consciousness is one thing, but whether you would be fully cognizant of what was happening to you is harder to prove. Anyone that’s experienced a faint or other sudden loss of blood pressure knows that things get pretty unreal (especially when almost inevitably coupled with your head tumbling to the floor and hitting things on the way down). You’ll be instantly dizzy, your vision will quickly narrow and get fuzzy as you black out, likely much quicker than the typical faint. I am as certain as I can be that despite technically retaining the capacity for conscious thought, actual decapitation is VERY likely to take the shape of a few seconds of dim, dizzy awareness that something is wrong (especially if you knew the killing blow was coming), but almost certainly not long enough to actually process what’s happened to you. One major issue is that the historical ‘evidence’ is mostly anecdotal and almost entirely unreliable. What we read about in old experiments with criminals, or even watch in modern ‘gore’ video clips is just brain death – nerves activating and the brain stem continuing autonomous function, trying to get oxygen where none is available. As one Reddit commenter below points out, you’d need to have someone on an EEG and cut their head off to be sure of what’s really going on. I have decided not to reprise the various historical (hysterical?) accounts of ‘living’ heads – not very scientific ‘experiments’ by Galvani, Aldini, Wendt, Seguret, Laborde, Lignieres, Lelut and Beaurieux (the celebrated 1905 case of the criminal Languille). For these, see chapter 8 of Frances Larson’s great book ‘Severed’. As Larson says, these efforts (many of which were inspired by arguments that the French guillotine was not as humane as it appeared) proved nothing either way and today can be readily explained as involuntary action. The same applies to the present-day ‘gore’ videos that can be found online. For those so inclined, and with an appropriately huge GRAPHIC CONTENT WARNING, here are three showing clear movement of eyes, mouth, and/or other facial muscles. We need to separate the technical persistence of consciousness from the observable effects. A head may be experiencing terrible pain and existential horror (although I doubt this, see below), but its face may or may not be moving at the time – there may well be no connection and chances are that the movement is involuntary as Davey suggested.
Interestingly, scepticism about the phenomenon of ‘lucid decapitation’ is as old as the claims themselves. As this article by James Elwick relates, Edward Rigby’s 1836 paper on the subject was;
‘“…immediately mocked in a rival medical journal’s editorial entitled “The Philosophy of Decapitation.”’
It proved so persistent however that in 1858, James George Davey actively sought to debunk these purely observational efforts with experiments of his own, published in his book ‘The Ganglionic Nervous System’. Depressingly, Davey carried out these tests on kittens, reaching the conclusion that;
‘…when the head is cut off, its irritability remains, as appears by the motion of the ears when pricked or touched with a hot wire ; and, as the extremities are also irritable, it will not be said that consciousness and sensation exist in two separated portions of the same body. Nor can it be admitted that sensibility and consciousness may remain in the head after separation ; for, if mere compression of the carotid arteries abolishes sensation and thought by interrupting the circulation in the brain, how much more must the superior violence of decapitation have this effect?’
This should have been an end of it, but the gothic horror of the living severed head was just too titillating. Despite other criticisms (notable French doctor and philosopher Cabanis, who was convinced that loss of consciousness was instant), for nearly 200 years now the popular media has recycled these claims as a way to send a shiver up the consumer’s collective spine (while they still have one). As ever, the internet has both promulgated these tales and offered the best means to debunk them. The main problem is separating the basic facts from the context. Davey understood the importance of this, but modern popular science outlets seem not to, reporting the facts on how long the brain is technically ‘conscious’ without qualification of just how aware one might be during the experience. Damninteresting.com has a good writeup that concludes that we don’t really know, but emphasises the horrific possibilities;
‘…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.’
In fairness they only say ‘surreal’, which is certainly likely. But could one really be meaningfully aware of what’s happening? How Stuff Works (quoting a figure from New Scientist) also admits the paucity of the evidence but is slightly contradictory;
‘…most modern physicians believe that the reactions described above are actually reflexive twitching of muscles, rather than conscious, deliberate movement. Cut off from the heart (and therefore, from oxygen), the brain immediately goes into a coma and begins to die. According to Dr. Harold Hillman, consciousness is “probably lost within 2-3 seconds, due to a rapid fall of intracranial perfusion of blood.”’
The figures on loss of consciousness are supported by (indeed, may even derive from) data from testing on rodents. Anna Gosline’s “Death special: How does it feel to die?” (New Scientist again, 13 October 2007) and Livescience reported respectively:
‘Quick it may be, but consciousness is nevertheless believed to continue after the spinal chord is severed. A study in rats in 1991 found that it takes 2.7 seconds for the brain to consume the oxygen from the blood in the head; the equivalent figure for humans has been calculated at 7 seconds.’ (New Scientist)
‘In 2011, Dutch scientists hooked an EEG (electroencephalography) machine to the brains of mice fated to decapitation. The results showed continued electrical activity in the severed brains, remaining at frequencies indicating conscious activity for nearly four seconds. Studies in other small mammals suggest even longer periods.’ (Livescience)
Digging down to the actual research level, this study by Rijn & Coenen showed that consciousness fades within 3/4s and may last up to 17s. Brain death comes around 1m. On the face of it, these figures are pretty terrifying. Even two seconds of full awareness would be truly horrifying – 17 doesn’t bear thinking about it. However, the human brain’s oxygen requirements for anything like full function are far greater than any rodent. Again, I suspect it’s very unlikely that you’d be genuinely ‘with it’ during those seconds. To summarise, we have lots of anecdotal evidence for facial movement after decapitation that doesn’t really help answer the question, and a lot of scientific evidence for ‘consciousness’ (tending toward 2-4 seconds) that doesn’t usefully convey what the real-life experience would be like. Short of an EEG and a willing victim, the provisional conclusion has to be that, if you were unfortunate enough to lose your head, yes you might technically still be conscious, but you’re really not going to know anything about it before (to paraphrase Ghostbusters II) your ‘head dies’.