Bichat’s idea fit prevailing views of brain injury
To a modern scientist, it’s easy to wonder why anyone would think a double-conk cure is reasonable. We now know that hitting the brain, or even shaking it, can cause temporary or permanent structural damage to neurons.
But, in the early 19th century the thinking was that concussion, or any brain injury, did not cause permanent structural or neuronal damage but a general “commotion” or “derangement” of the brain. It was generally thought that concussions, or any imbalance in the brain, could cause problems in thinking and memory, and could also lead to insanity. So Bichat’s proposal of brain symmetry and a second blow helping to “rearrange” the problems caused by a first blow fit into the prevailing view about concussions.
Later on Victorians also thought that any type of “nervous shock” caused a physical effect on the nervous system. Electricity could provide a nervous shock, as could terror, grief or a blow to the head. All physical or emotional shock was considered to have the same effect on the brain and nervous system.
Many problems were thought to be the result of an unbalanced brain. Indeed, several early and mid-19th-century practitioners believed shocks, whether physical or emotional, could be useful to bring someone out of coma, or a stupor. Hysteria, a catch-all diagnosis often given to women for a wide variety of “nervous” symptoms, was sometimes treated by slapping the patient.
Considering that many Victorians saw the brain as a machine it may have appeared reasonable to them to “knock some sense” back into someone. A shock to the system would get the cogs moving again and bring the brain back in balance, like someone hitting a machine on the side to get it working again.
What about amnesia?
So how did all of this become connected to amnesia? While Bichat wrote only generally about “intellectual” problems, it had been known since ancient times that traumatic brain injury could cause memory problems. However, there was another prevailing myth circulating at the time that memories could never be lost. This was also was reinforced by “pop psychology” writers of the 19th century.
Many of us have had the experience of a “memory jog,” or a cue that brings up a long forgotten memory. Perhaps because our own experiences serve as powerful evidence to us, this also reinforces the myth that all memories are forever stored in the brain and only need some sort of jolt to come back.
It’s hard to know exactly how the double-conk myth became intertwined with the myth of memory restoration, but forgetting and amnesia were also popular themes in Victorian novels. If memory could be restored with a shock, a second conk could provide that jolt.
It wasn’t until the middle of the 19th century that a few scientists studying memory began to fully realize that a blow to the head might destroy some memory abilities completely. A second blow wasn’t likely to jump start the brain, they realized, but create further damage.
But the double-conk myth was already in circulation by then. The fact that the myth was originally supported by some scientists and physicians probably lent it some credence even as evidence that it wasn’t true mounted. It’s hard to change a myth with a 50-year head start.