Don’t ask me how or why, but I got to reading up on childhood amnesia, i.e. how we don’t remember our infancy and early childhood, and it’s some interesting stuff, with some perhaps interesting implications for helping the ageless (or biologically immortal) people who may arise in the future from becoming stagnant, crusty, and set in their ways. After all, we don’t really want to be dominated by a class of people who look young in body but who are far more inflexible in mind than even the most insufferable boomer, do we?
Why do we forget Childhood?
It’s often assumed that infantile amnesia arises from the brain structures for long-term memory not being there yet, and while this probably does have a lot of truth to it, it’s almost certainly not the full story; by all appearances the parts of the brain associated with long-term memory reach their adult configuration by ages 3-4, yet long-term memory remains impaired for a long time afterwards.
A quite longer time afterwards than I would have thought! My own first clear memory is from the age of 23 months, i.e. shortly before age 2, which apparently is pretty early, though far from unheard of. Some people remember literally nothing before the ages of 6 or even 8, which strikes me as a little weird, but whatever.
Anyway, it’s clear something else is going on. One of the more intriguing ideas is that infantile amnesia is a product of high levels of neurogenesis, the generation of new neurons, which helps the mind learn and be much more flexible and plastic; this hypothesis holds that neurogenesis degrades long-term memory, and it would seem could explain a lot. In particular, the peak ages of neurogenesis exactly correspond to the ages at which childhood amnesia is at its peak. And in animal studies (yes, animals also have childhood amnesia, just like people) a causal link between increased neurogenesis and increased long-term forgetfulness has been established. Hmm.
Immortals with the Memory of Small Children
Where it gets fancy is that the human brain grows and develops during early childhood like no period before or later, having an unparalleled capacity for learning, so if you could somehow (genetically) engineer the human brain to remain in that condition throughout life instead of it cutting off in middle childhood you would end up with a much smarter, much more flexible, but also much more forgetful population, which I’ve posited is exactly the sort of brain we’ll need once we conquer old age and rejuvenate ourselves.
Interestingly, the engineering of such a faculty would likely be much easier than I thought originally. Consider that this would entail not editing in a wholly new genetic trait but just extending a trait found in childhood so it doesn’t ever go away, the technical term for which is neoteny. A classic example is how dairy-farming populations in Europe evolved lifelong lactose tolerance (a trait originally found only in children), but neoteny is found across a wide variety of human traits and throughout the animal kingdom.
I’d expect that a population that had lifelong infantile amnesia would, like small children, be able to remember events from up to a few years earlier but the sort of memory retention over decades that we have as adults would no longer be a thing. While this might be kinda sad, keep in mind that we can leverage technology to create a mind-bogglingly comprehensive variety of records that we can refer back to (photos and videos more or less serve this purpose for a perhaps disturbingly large number of people as it is…).
Rejuvenation of Mind, not just of Body
Weird as it might seem to posit that biological immortality in order to work would need to be coupled with an early-childhood-like memory pattern, such a resort might actually be necessary. Consider that a certain point memory is a burden, tying us to the past and warding us off from so many possible futures, becoming an encrustation around our whole identities, holding us back from becoming all we could be. For example, how many of us vividly remember a good or bad experience with something from decades ago that still helps us to define who we are, what our worldview is, and what is possible for us?
The effects of this are already noticeable in elderly people, but it usually doesn’t become a severe problem during the century or so that humans live. But what if people lived much longer? Imagine the sort of memory burden carried by the elderly today, only multiplied by five times; now you might be starting to get a bit nervous, but that’s only the start! Without old age to cut us down we’d live for 858 years on average, and that’s with our current society’s young-adult mortality rates, which could easily be much lower in an advanced society of the future, correspondingly lengthening lifespan.
Imagine a population with the sort of encrustation of memory experienced by elderly people today, only a hundred times worse; that’s a real possibility, one which could easily stagnate and ultimately destroy a society if it’s not redressed and headed off as soon as feasible, which, judging by how the “keep the brain like a sponge that doesn’t form decades-long memories” would just involve genetically engineering neoteny and biological immortality would likely involve genetically engineering in entirely new traits, might actually come sooner than the ability to conquer old age! Hmph. Funny how that works out.
I know it might sound a little weird, but if you ask me this is the level of thinking that will be required to both defeat aging and defeat gerontocracy, two ambitions we should set for ourselves in the future if we are to meaningfully grow and advance as a people. The good news from the neurogenesis theory of childhood amnesia is that we could, in effect, kill two birds with one stone, which I find quite interesting.