« Chairman Dean | Main | Analysis Of Stern »
I'm Defective
The Washington Post reports that yours truly is prone to overly risky behavior:
A National Institutes of Health study suggests that the region of the brain that inhibits risky behavior is not fully formed until age 25, a finding with implications for a host of policies, including the nation's driving laws.Query: Is this really news? Everyone knows that the proverbial young people are more wild and crazy than our elders. I thought it was already conventional wisdom that teen behavior patterns typically fade as people pass through their 20s rather than disappearing suddenly when you graduate from high school. Animal House? Additional query: Are there good reasons for young people to be designed as more risk-friendly than older people? In the world of investing, for example, it's considered the pinnacle of sound financial management to have young people hold relatively risky portfolios and then gradually decrease risk exposure as you age. Is there some more general logic to this?
"We'd thought the highest levels of physical and brain maturity were reached by age 18, maybe earlier -- so this threw us," said Jay Giedd, a pediatric psychiatrist leading the study, which released its first results in April. That makes adolescence "a dangerous time, when it should be the best."
February 2, 2005 | Permalink
TrackBack
TrackBack URL for this entry:
https://www.typepad.com/services/trackback/6a00d8345160fd69e200d83422464f53ef
Listed below are links to weblogs that reference I'm Defective:
» Teen Brain Scans: A rebirth of Phrenology? from One and Four
Matthew Yglesias brings up an article in the Washington Post yesterday that cites a new study that 'proves' the inferiority of teenage, and indeed early 20-year-old's brains. Apparently I am a danger to myself and others around me because of... [Read More]
Tracked on Feb 2, 2005 1:17:40 PM
» Teen Brain Scans: A rebirth of Phrenology? from Oblivion Dot Net
Matthew Yglesias brings up an article in the Washington Post yesterday that cites a new study that 'proves' the inferiority of teenage, and indeed early 20-year-old's brains. Apparently I am a danger to myself and others around me because of... [Read More]
Tracked on Feb 10, 2005 11:31:11 PM
Comments
My understanding that the rationale behind younger people holding riskier portfolios is that, since they have longer before they retire, they have more time to recover if their financial risks don't pay off. If your stocks crash and burn when you're in your 20s, so what? You still have plenty of time to start over and save for retirement. As you get older, and as you (presumably) build up some savings, it makes more and more sense to play it safe.
Posted by: Alex S. | Feb 2, 2005 11:40:53 AM
"Are there good reasons for young people to be designed as more risk-friendly than older people?"
Sure; The young people are the followers, who are risking only themselves. The older people are the leaders, who must be more risk adverse, because they're risking everybody they lead. And the leaders need foolish cannon fodder to expend defending society... Risk adverse cannon fodder would refuse to be expended.
Posted by: Brett Bellmore | Feb 2, 2005 11:47:26 AM
Matt,
I recall a study done a few years back, which examined the evolutionary advantages of risk-taking. In a nutshell, it said that those animals whose survival instinct was slightly supressed had a better chance of actually reaching maturity than those who were more more risk adverse.
In other words, you sometimes have to take chances to get ahead. Once you've survived to maturity (child bearing age), however, it is more advantageous to play it safe -- because at this point, generally speaking, you have offspring who are depending on you to ensure their own survival.
Posted by: SMASH | Feb 2, 2005 11:50:14 AM
With investing, I think the issue is not age, but time left until retirement. If you are planning to retire at 30, you should have a conservative portfolio, even though you are young.
Posted by: sc | Feb 2, 2005 11:55:40 AM
It sounds like an intelligent design to me.
Posted by: mikey | Feb 2, 2005 11:58:57 AM
any adaptive content that "men under 25 are more risk prone" might have shouldn't be rationalized on the basis of recent (very recent) life expectancy statistics (unless you have a Whiggish view of evolutionary adaptation). This is certainly true in spades for the financial planning aspect of this, which has to do with "time until retirement and the end of labor income" statistics, not age statistics.
Plus, there's a bit of a Liar problem, since from a financial planning perspective, it's prudent for the younger investor to be riskier than the older investor. A hyperrisky youngster would seemingly ignore this prudent advise and do something stupider (like not save at all?)
Posted by: David | Feb 2, 2005 12:17:59 PM
Query: Is this really news?
Yes. Well, if it's true, it's news.
Not to snap at Matt (who I know knows better), but I hate this frequent reaction to announcements of scientific studies, usually followed by sentiments that scientists have their heads up their ass and how dare they spend (some wildly exaggerated percentage of) my tax dollars "proving the obvious."
No, it's not news that part of our conventional wisdom is "young people take risks." Nobody said it was. But it is news is if there is strong empirical evidence to back up conventional wisdom. Of course, it's more interesting when science refutes commonly held beliefs (e.g. "heavier objects always fall faster"), but given human fallbility, it's also interesting, important, and often even useful when science can put our hunches into a rigorous framework.
Anyway, if I understand this excerpt, the key point is that a certain brain region is not fully developed until age 25. That's more specific than just saying that for some reason or other, we engage in less risky behavior. If you accept the premise that older people take fewer risks, you could explain it in a variety of ways. Two that come to mind are: (a) we learn from the consequences of risky behavior (b) we have more to lose relative to gain as we get older.
If the answer is (c) there's a clump of neurons that hasn't finished developing and when it does, we become less inclined to take risks, then I would call that BIG NEWS, news that calls into question all of our previous attempts to deal with excessive risk-taking in young people.
Posted by: Paul Callahan | Feb 2, 2005 12:18:58 PM
Well yeah: (1) young people have less to lose-- no family, no mortgage, no career or reputation to speak of. Older people can't do reckless things for fear of hurting their family, losing their home, getting fired, etc. (2) Young people have more time to recover from mistakes. If, for example, they have a risky portfolio that tanks in their 20s, they have their 30s, 40s, and 50s to rebuild their savings. A 50-year-old can't do that. (3) Young people lack the life experience to distinguish good risks from foolish ones. (4) Youthful vigor makes it easier to bear the bad outcomes of risky behavior. (hangovers, small businesses that don't pan out)
Posted by: Tim | Feb 2, 2005 12:32:14 PM
While I take Paul Callahan's point, I seem to recall that insurance companies traditionally identified the relevant inflection point for drivers as being 25, not 18.
Posted by: Jacob T. Levy | Feb 2, 2005 12:38:56 PM
I don't think the concerns are about investing. While you are of course quite right that younger people should take more investment risk, there's a difference between sensible risk (putting most of your portfolio into stocks) and dumb risk (putting all your money into your brother-in-law's get-rich-quick scheme). If young people are doing a lot of the latter, that would be a problem. The real concern, however, is risky behavior that endangers others (crime, reckless driving) or is otherwise destructive to society. The fact that risk-inhibiting mechanisms don't mature until 25 calls into question policies relating to minimal driving, voting, and armed forces enlisting ages. Many people between 18-25 may not be ready to handle these responsibilities. (On the other hand, many people past 75 shouldn't be driving either.)
Posted by: Rebecca Allen, PhD | Feb 2, 2005 12:43:31 PM
investing? bad example. Risk aversion or friendliness is way older than the invention of modern investing. Try sneaking around in the dark of the night looking to raid your nieghbor for livestock or maybe a wife. That is risk friendliness for ya.
Posted by: j swift | Feb 2, 2005 12:45:14 PM
If you think about this from an evolutionary perspective, this behavior evolved when people lived to be about 40. A typical guy would be wild and crazy and have lots of fun for about 25 years, and then be stolid and boring for about 15. Today, you're more likely to live to 80 and be boring for the vast majority of your life. It's kind of depressing when you think about it.
Posted by: ostap | Feb 2, 2005 12:45:58 PM
The evolutionary reasons here are not valid. Brett Bellmore is providing a group selection dynamic, which would be a much more amazing discovery on its own.
The idea that people do not have much to lose when young is actually the reverse -- if you have not reproduced, you have a lot more to lose. If you have reproduced risk (in an evoltionary sense) decreases with each child.
BTW, I am assuming natural selection when Matt uses the phrase "reasons for young people to be designed as...".
When considering how the brain forms and what life expectancies were, and age of procreation was, it seems more likely that the stabilization of the brain is more of a design flaw resulting from natural selection not having enough pressure to fix the problem* -- kind of like the aging of the rest of the body ("Why do hearts fail in people over 80?".
*After children are born the natural selection pressures on keeping people alive decrease with each child.
Posted by: theCoach | Feb 2, 2005 12:49:13 PM
Paul Callahan took the words right out of my mouth: what's news is not the observations about behavior, but the evidence for the biological mechanism by which this behavior may operate.
As other people have pointed out, younger people have less to lose and more to gain from risky behavior, so whether for biological reasons or social ones, it's not surprising that the young are more willing to take risks. That's not what makes this study interesting or newsworthy.
Posted by: janet | Feb 2, 2005 12:50:10 PM
Query: Is this really news? Everyone knows that the proverbial young people are more wild and crazy than our elders.
Yes, its news that there is a demonstrable biological reason to justify this conventional wisdom. "Everyone knows" things that aren't true very frequently.
Posted by: cmdicely | Feb 2, 2005 12:55:15 PM
The evolutionary argument could go either way: after you've finished reproducing, any genetic traits that influence your future survival would be irrelevant to natural selection, though of course not to you personally. (Or mostly irrelevant: there are other mechanisms at work.)
Also, we're all assuming that this aspect of brain development is genetically programmed, which is not necessarily true.
Posted by: janet | Feb 2, 2005 12:56:50 PM
Additional query: Are there good reasons for young people to be designed as more risk-friendly than older people?
The question includes the implicit premises that (1) young people are "designed", and (2) they are "designed" separately from old people.
But, in a social animal, there might be benefits to that, especially if there was a tendency to defer to older people when they are present, also; this would make stable communities (i.e., ones where the status quo behaviors are successful) more risk averse and unstable communities where there are less surviving elders less risk averse and more prone to experimentation, making change in course and development of new traditions most common where the status quo behaviors aren't working.
Posted by: cmdicely | Feb 2, 2005 1:00:57 PM
The evolutionary argument could go either way: after you've finished reproducing, any genetic traits that influence your future survival would be irrelevant to natural selection, though of course not to you personally.
This is, of course, completely wrong, since reproductive fitness means that your offspring are not merely born but survive to reproduce; traits which affect your survival after reproduction are relevant to reproductive fitness, though the relation may be complex. If you can still reproduce, there is a clear opportunity for further fitness, even if you have already reproduced. If your continued life helps your offspring survive to reproduce, then your continued survival is still beneficial to your reproductive fitness, even if you don't reproduce any more. If your continued life just means you, no longer capable of further reproduction, compete with your offspring for resources without contributing, then your continued survival is detrimental to your reproductive fitness.
Posted by: cmdicely | Feb 2, 2005 1:04:35 PM
is there any correlation between higher risk tolerance and higher randiness? therein may be the key, the rest is civilized windowdressing.
Posted by: David | Feb 2, 2005 1:05:08 PM
For years I've argued that the driving age should be raised to 25. Glad to see there's a scientific basis for this.
Posted by: Tom Hilton | Feb 2, 2005 1:05:08 PM
is there any correlation between higher risk tolerance and higher randiness?
Can we ask a 19th century whaling expert?
...if this riddle be worthy, Yaaaaar!
Posted by: Paul Callahan | Feb 2, 2005 1:08:03 PM
"The evolutionary argument could go either way: after you've finished reproducing, any genetic traits that influence your future survival would be irrelevant to natural selection, though of course not to you personally. (Or mostly irrelevant: there are other mechanisms at work.)
Also, we're all assuming that this aspect of brain development is genetically programmed, which is not necessarily true. "
Posted by: janet
Just remember that "after you've finished reproducing" can be very late in life - just as much for women as for men.
Posted by: Barry | Feb 2, 2005 1:08:47 PM
I don't know what you mean by "very late in life," but it's not true that women can continue reproducing as long as men can. Believe me, I know from experience! Female fertility drops off starting as early as the early 30's and falls significantly over the next decade. By age 45 very few women are still fertile. (Of course, this is not an absolute: it's not that conception is impossible in most 45-year-old women, just very, very unlikely.) Male fertility also drops off with age, but the process is much more gradual.
Posted by: janet | Feb 2, 2005 1:22:09 PM
cmdicely: Notice that I said "after you're finished reproducing," rather than "after you've reproduced."
I'm aware of arguments about kin selection. That's why I added "(Or mostly irrelevant: there are other mechanisms at work.)," which I notice you left off when you quoted me. Kin selection is a factor in evolution, but in my opinion it gets more play than it really deserves.
Posted by: janet | Feb 2, 2005 1:30:47 PM
I would suggest that people not use this as a basis for suggesting policy. This study doesn't tell us anything about the rationality of risk-taking by the young versus the old. It only tells us that young people tend to be less risk averse than old people. Ironically this might mean that young people approach risk more rationally than old people. Actuarial data is probably much more helpful in this regard. Additionally, I would suggest that even if appetite for risk is neurologically controlled, perception of risk is not. Naturally risk averse codgers might still engage in lots of irrationally risky behaviors because they don't properly understand the risk/rewards. I would a plea that no one call for a 25 year old minimum on booze, cars and voting.
Posted by: Finn | Feb 2, 2005 1:34:25 PM
The comments to this entry are closed.
