Longevity: think of yourself now, and yourself in the future

Imagine yourself now – are you dedicated? Now imagine yourself in 10 years – are you dedicated? Differences in your brain activity dependent on these two different questions might be fundamental to the future of longevity research and society in general.

The future of the longevity field and society

To take longevity research seriously it almost seems a default that you must be forward thinking – and be able to value the future. However, for further advances in the field, society at large (which remember is composed of the average citizen), and the government must also value the future, or why would they be interested in funding and supporting aging/longevity research and other research or decisions important for the very-long term benefits to society (think of the long now foundation).

The longevity field has made great advances in the last 5-10 years and there appears to be a large rise in the public interest in this research (possibly fueled by baby boomers – but in the research labs the current young generation of researchers are stepping up the pace of research).

But I am not going to talk about what you might expect regarding the future of the longevity field. I am not going to talk about the discovery of new pathways and molecules that might result in increased lifespan. Rather, I will talk about maybe a more important aspect of future longevity – which is in the form of how humans think of the future.

Humans and inability to think rationally of the future:

Humans (and other organism studied) do not have a rationale approach to the future (and many other things). And unless we have at least a closer appreciation of the future then it is less likely we will do the correct things now to insure a better future. This would include everything from looking after our environment, to looking after your individual health, to both personal finances (savings) and governmental financial health – not to mention the foresight to perform longevity research – as one example).

The best example of human’s irrational dealing with the future is what is called hyperbolic discounting (also called: temporal discounting, or future discounting). Hyperbolic discounting is the human preference for small immediate reward over larger future payoffs. The further the time in the future of the reward the greater the discounting – but not a linear ‘rationale’ discounting but rather a hyperbolic level of discounting.

For a real world example, if I offered you 10 dollars now or 14 dollars that I will mail you in two weeks which would you take (in the research paper I discuss down below real money was involved and  if the subjects choose the delayed higher reward the money was actually mailed to them, or they could be handed the 10 dollars immediately) . To make a long story short most people do not make the rational choice of the delayed higher reward in two weeks (while the exact dollar figures I give might be a little off – you get the idea). Humans are generally bad at delaying rewards and hence we too easily take the immediate smaller reward rather than delaying our immediate gratification for a greater reward in the future.

You can see how this is important for possibly the fundamental problem of our current financial crisis. People saving rates have dropped dramatically over the last 20 or so years, and too many people who could not afford the immediate reward of a house decided they could (of course this was helped by the agencies that lent out money to people who could not really afford the loan – but at the end of the day the individual made the ‘rationale’ choice of taking this loan).

Humans lifespan has increased greatly over the last 100 years, to the point it is said that we have gained more years of lifespan in the last 100 years compared to probably the last several thousand years. The question then becomes has our brain adapted to deal with a longer lifespan – with the cognitive ability to adjust our behavior for this longer lifespan – this longer future?

Research paper:

A recent study by Ersner-Herschfield et. al., 2008 (which I was also able to hear author present his work at the latest SFN meeting) from the respected Knutson group at Stanford university, examined what brain areas might be involved in future discounting.

Background:

Now the general notion behind this paper is that people that have a high level of future discounting might view their future self differently than those that display less future discounting. Maybe it is the ability to appropriately imagine our future self that plays an important role in our future discounting.

Previous work has shown that when individuals think of themselves versus thinking of others there is a stronger activation of the rostral anterior cingulate (rACC) gyrus (anterior cingulate cortex). So the authors wondered if there would be differences in rACC activation depending on if we imagine ourselves in the current time, or in the future. Is the imagination of ourselves in the future more resembling of how we think of others (strangers)?

There were four conditions in which the subjects answered a question (which the subjects rated as: very unlike, somewhat unlike, somewhat like, very like): Does this word describe you now, Does this word describe you in 10 years, Does this word describe Matt Damon/Natalie Portman (depending on your sex) now, Does this word describe Matt Damon/Natalie Portman in 10 years?

Matt Damon or Natalie Portman might not be true strangers but they are ‘others’ that all the subjects were familiar with.

And one other question was used as a control: Is this word in all capital letters?

A total of 18 positive and 18 negative words were used, e.g Honorable, Honest, Liar, Unreliable. Words similar to these were used for all 4 conditions – you now, you in the future, a stranger (‘other’) now, a stranger (‘other’) in the future (as outlined above).

While the subjects were answering these question on the very unlike, somewhat unlike, somewhat like, very like scale their brains were scanned with a MRI machine. Then the researchers could determine if there were differences in brain activation between all these conditions.

Results:

In agreement with previous research there was more activation of the mesial prefrontal cortex (MPFC) and the rACC region when judging self qualities versus a stranger (Matt Damon/Natalie Portman) qualities, which agrees with previous research (Northoff et. al., 2006).

Overall, the researchers found differences in the rACC activation depending on if people imagined themselves in the current, or in the future. However, as an important control there were no differences between the subjects imagining the qualities of the stranger (Matt Damon/Natalie Portman) now or in the future. This means judging the qualities of the stranger did not depend on the time scale (now or the future) while there were differences in self judgment of these qualities when imagining themselves now or in the future.

But of course there were individual differences in activation of rACC when comparing now self versus future self. So the researchers took the same subjects one week after the brain scan and formally tested their individual future discounting rate (e.g how hyperbolic was their future discounting).

Now for the most interesting result – there was a correlation between the level of future discounting and rACC activation. The subjects that had the highest level of future discounting (preferred immediate reward over delayed higher reward) had the most difference in the rACC when thinking of their current selves vs future self. As in their future self resulted in less rACC activation.

The implication is that the subjects with the greatest level of future discounting (the most irrational)  saw their future self more like an ‘other’ person, a stranger, as compared to those that were more rationale and displayed less future discounting, which saw their future self similar to their current self – not as a stranger. And you can only imagine that if you think of your future self as a stranger – a non self – then why would you delay gratification to help out this stranger of the future – it wasn’t even you.

Take home messages:

It might be argued that Homo sapiens evolved to survive and reproduce in a far shorter time frame than modern man now lives. Hence, the general cognitive ability to think of some future time and adjust behavior to have long term benefits for themselves, their children, and society, might be too short of a time period to optimize our benefits when we are living so many more years than we did in the past.

Until the last couple hundred years their was a very high level of uncertainty if one would survive to the next year (not to mention just plain shorter lifespan). The uncertainty of living the next year, or the next 10 or 20 years has dropped dramatically in the last 100 years but maybe our brain has not kept up with our education/cultural changes that have resulted in a reduced uncertainty of living for another year.

Yes, we have dramatically changed our behavior in the last 5-10,000 years to become more future thinking in the form of planting in the spring to harvest in the fall, and to store food for the near future (depending on how long our food could be stored). But even the future thinking gains we have developed with agriculture and storing food most of us are not rationale when making decisions regarding the future – because we still discount the future too much.

But I propose here that unless humans soon become better at thinking about the future – and not discounting it so much – we might not be able to make the changes we need for a better world and society. Unless we can think of the repercussion of using all our energy (without coming up with alternatives) and polluting our environment to a dangerous level we are unlikely to take the long term and difficult steps to turn things around.

The same could be said about longevity research – if we can not imagine ourselves living longer and healthier lives – and not imagine it as only happening to a ‘stranger’ we our unlikely as a society to invest in this imagined future.

I would think if you did brain scans of the scientist and organizers of both environmental and longevity research/organizations (e.g. Methuselah foundation) you would find that they think of their future self not as strangers but as themselves (higher rACC activation).

However, one can imagine and hope for the future without actually making changes to ourselves in the current time – such as doing the small daily things such as eating as healthy as possible and exercising (for this is all we have currently that will on average improve our future life).

Now in reality things might be a bit more complicated about rACC activation and future discounting (as with most science) and I will add to the story tomorrow. (Update – click here for the followup blog piece)

Also, while the Knutson group might have found an important brain structure that is involved in our irrational future discounting the real work becomes of how to ‘exercise’ the rACC (our future thinking ability) when we think of ourselves in the future so us humans reduce our discounting of the future. It could be argued that until our society at large improves their ability to appropriately value the future it will be hard to move forward in a large number of important endeavours including the environment and longevity research (to mention a few).