You probably know the quote by Steve Jobs saying that death is life’s single best invention because it gets rid of the old and makes room for the new. This view is the core of another fairly common objection to rejuvenation, codename “cultural stagnation”.

Wouldn’t all those rejuvenated people, however physically young, be always old people “inside”, and drag everyone down with them into their anachronistic, surpassed ways of thinking, making it harder for fresh ideas to take hold, ultimately hindering social progress and our growth as a species? Maybe it’d be best not to take the risk, forget rejuvenation, and be content with old age as it is.

Well, try explaining to your grandfather that the reason he has to put up with heart disease is that we’re afraid people his age may all become troublemakers when you let them live too long.

Facts, please

Joking aside, this concern implies that the death of older people is somehow essential to the thriving of society, and that is one heck of a bold claim; as such, it requires extremely solid proof, because we can’t ask people to give up good health and life over someone else’s worst-case-scenario guesses.







Do we have compelling evidence that elderly people tend to be so conservative that enough of them may actually have a negative effect on social progress, or is it just a stab in the dark based on stereotypes? Are there any studies showing that people who live past a certain age inescapably become a drag on the advancement of the species, or do we say it out of a hunch? Assuming such a tendency to conservatism in the elderly exists, is there any proof that it’s an unavoidable consequence of age that can’t in any way be interfered with?

In my humble opinion, until the questions above can be unequivocally answered affirmatively, the thought of forestalling this hypothetical catastrophe by opposing the development of life-saving medical biotechnology shouldn’t even cross our minds. Even then, denying medical treatments to a few who might be a hindrance to society—or, worse, not developing the treatments at all, precluding their use to everyone, “good” and “bad” guys alike!—doesn’t seem a very ethical way to “make room for the new”.

In any case, we can’t predict the future, so we can’t rule out any doomsday scenario with 100% accuracy. The best we can do is figuring out how much if at all, rejuvenation biotechnology might contribute to this problem and if there wouldn’t be a way around it that doesn’t involve letting people die—the traditional go-to type of solution.

Socio-cultural contributors of stagnation

If the problem is cultural stagnation, I don’t think preventing people from living too long will solve it: conservatives can be found among old and young, and the same is true of progressives. Besides, aging kills old farts and old innovators alike, offering no guarantee that the generational turnover will necessarily lead to a majority of open-minded people. Leaving the matter up to Nature on the assumption it will surely do what is best is a rather simplistic and short-sighted approach to the problem.







If old people today tend to be resistant to change and stick to their ways, it’s likely because elderly of today come from an age when knowledge wasn’t readily accessible to everyone and the stages of life were still somewhat set in stone: birth, school, work, family, retirement, death.

In this framework, it’s clearly easier for young people to think out of the box and be more open to change since they’re starting essentially from a clean slate and are ready to absorb new information. A lot of the knowledge youngsters have access to was generally not available at all when their elders were young. On top of that, as continuous learning isn’t really a thing in this framework, new knowledge isn’t accessible to old people even later on.

However, old people aren’t automatically closed-minded and opposed to change. Factors such as education, socio-cultural context, and access to learning opportunities play a big role in this sense. If you’ve been brought up in a progressive, open environment, and have been taught to listen to others, maintain a healthy skepticism even about your own convictions, never stop learning, and never let your gut take your brain’s place when considering a new idea, why should you suddenly forget all of that and become the exact opposite of yourself in your old age?

Since we’re currently living in an age of ever-increasing free access to the whole of human knowledge, and continuous learning is actively promoted as a good thing, is it reasonable to expect that young people of today, used to this new way of life, will throw it all out the window and turn stubborn, ignorant, and reactionary once they hit old age? A society is only as retrograde and culturally stagnant as its members, and as long as we’ll strive to keep them open-minded and grant them access to knowledge, their age is unlikely to matter much.

Biological contributors of stagnation







The factors discussed above certainly make a big difference to whether you’re an innovator or a drag on progress, but they’re likely not the whole story. Neuroplasticity is the property of the brain to form new connections between neurons, and thus ultimately the brain’s ability to reshape itself, which enables us to learn new ideas, habits, ways, and thus change our minds. As such, it is definitely a necessary condition for open-mindedness: if your brain can’t rewire itself, you’re going to have one heck of a hard time learning new things or appreciating change and novelty.

Younger brains are generally more plastic than older ones, and they have more pronounced neurogenesis (the ability to grow new neurons), as explained for example in this TED Talk. The talk also explains how neurogenesis and its benefits can be fostered, giving us some control on our own open-mindedness. However, my point is that, if neuroplasticity and neurogenesis are properties of young brains, sufficiently comprehensive rejuvenation therapies might be able to restore it.

This isn’t just my own fantasy. We already know that brain plasticity can be induced. For example, the discovery that antidepressants restore neuroplasticity back to more youthful levels in the cerebral cortex of adult rats has been quite a hot topic in the past years [1], [2]. This effect has been noticed even in the visual cortex [3], and it could be induced even without the use of drugs [4].

Closer to home, a study on senescent cell clearance showed that elderly mice whose senescent cells were regularly purged exhibited some behavioral traits typical of younger mice, such as exploring their cage as opposed to sticking to its sides most of the time [5]. Hard to say at this point if senolytic treatment has had an effect on the mice’s brain in terms of plasticity, but this result is certainly intriguing and a cause for optimism.

We can’t jump the gun and conclude that rejuvenation biotechnology will necessarily be able to restore youthful neuroplasticity to a brain of any age, but there is evidence that manipulating brain plasticity pharmacologically is possible; if there is a biological limit to how open-minded and able to learn aged people can be, then interventions might help us bypass it.







Meanwhile, as they say, let’s be the change we want to see in the world: if what we want is a society of open-minded, progressive, and change-friendly people, let’s keep our minds sharp, open, and plastic with the simple tools available today while we wait for rejuvenation to come to the rescue.

Literature

[1] Castrén, E., & Antila, H. (2017). Neuronal plasticity and neurotrophic factors in drug responses. Molecular Psychiatry.

[2] Karpova, N. N., Pickenhagen, A., Lindholm, J., Tiraboschi, E., Kulesskaya, N., Ágústsdóttir, A., … & Hen, R. (2011). Fear erasure in mice requires synergy between antidepressant drugs and extinction training. Science, 334(6063), 1731-1734.

[3] Vetencourt, J. F. M., Sale, A., Viegi, A., Baroncelli, L., De Pasquale, R., O’Leary, O. F., … & Maffei, L. (2008). The antidepressant fluoxetine restores plasticity in the adult visual cortex. Science, 320(5874), 385-388.







[4]Baroncelli, L., Sale, A., Viegi, A., Vetencourt, J. F. M., De Pasquale, R., Baldini, S., & Maffei, L. (2010). Experience-dependent reactivation of ocular dominance plasticity in the adult visual cortex. Experimental Neurology, 226(1), 100-109.

[5] Baker, D. J., Childs, B. G., Durik, M., Wijers, M. E., Sieben, C. J., Zhong, J., … & Khazaie, K. (2016). Naturally occurring p16Ink4a-positive cells shorten healthy lifespan. Nature, 530(7589), 184-189.