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Science

Mind Scans to Map Decision Making Mechanics 218

rrangel writes "Newsweek is running an article on the fMRI, which tracks brain function by measuring blood flow, and using it for watching the mechanics of economics and choice. Best quote on economic choice: '... there is no quantity of juice sufficient to get a male monkey to look away from the hindquarters of a female in estrus.' H. Hefner has known that all along."
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Mind Scans to Map Decision Making Mechanics

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  • fMRI (Score:5, Informative)

    by bcaffo ( 681613 ) on Monday June 28, 2004 @08:37AM (#9549763) Homepage
    It's great to see fMRI getting some press, but the article fails to mention some of the important limitations of the technology. The magnitude of the signal is only 1-5% over the noise and comparisons need to be made at thousands of locations. Also only very simple tasks can reasonably be studied. Regardless, the technology has great promise in medical applications. I am currently invovled in a a study where fMRI is accurately distinguishing between patients who are at high risk for AD and controls. As an additional plug, I think quantitative neurology is great area for CS, Math etc types to get involved in.
  • by orthogonal ( 588627 ) on Monday June 28, 2004 @09:20AM (#9550055) Journal
    We [humans] don't need that the female be in estrus.

    And with good reason: human females, almost uniquely among animals, conceal when they're fertile.

    In fact, they conceal it so well, the women themselves don't know when they are fertile. At least not consciously: human females do show preferences for different types of males depending on whether or not they're fertile. Fortunately or not, depending on whether you're looking to have offspring or just consequence-free sex, human females will tend to prefer the more rotund and nerdy Slashdot-type male when she's not fertile, and very masculine hunks when she is fertile.

    (Unlike fertility, there are somewhat obvious signs of how masculine a human male is: higher testosterone produces both dominant behavior and a thinner, more "cut" physical appearance, especially about the face. Female humans may not be able to consciously articulate why some males seem more masculine than others, but unconscious parts of their minds, adapted by evolution, can spot those signs.)

    And rather than just be fertile at certain times of the year, human females are fertile all year 'round. This is not in order to allow greater numbers of offspring to be produced, because in our natural hunting and gathering condition, a human female can only support about one offspring every four years. Until the beginnings of agriculture (until recently thought to be about 10,00 years ago, recently pushed back to about 23,000 years ago), natural fertility suppression caused by breast-feeding and, if that failed, infanticide, suppressed additional offspring.

    So why be fertile all the time? Well, if a female is fertile all the time, the male must be interested in sex all the time, as the parent poster pointed out, because he never knows when sex will result in progeny. The male may not consciously want offspring; he just wants sex, as those males not wanting sex never had offspring to pass that lack of desire on to. So continual male desire for sex is promoted by the sax evolutionary strategies that also promote non-seasonal but concealed female fertility.

    What's the benefit to the female of the male's unrelenting interest in sex? The male's desire for sex keeps him around continuously -- and that aids, not the female, but the offspring. The male will barter for sex by giving the female and her offspring the highly concentrated protein and fat in the meat that the male hunts. By concealing ovulation, the male never knows when he can safely forego the sex, keeping the nutritious meat for himself until the female is fertile and sex will result in the male's progeny.

    But there's even more to it: because fertility is concealed, the male cannot safely allow other males to copulate with "his" female -- as those other males might win the lottery of the female's fertile days. So concealed fertility also promotes pair bonding.

    But if the female does manage to sneak off and copulate with another male, she can get meat from that other male for herself and her offspring -- giving her an incentive to "cheat". So the same pair bonding that cements a male to "his" female also leads, inevitably, to jealousy, fratricide between males, and even male violence toward his mate, to "keep her in line".

    And once again, concealed fertility aids the female -- since the male can never be sure when the female conceives, he can never be sure that a particular child is his; he must take his chances and support all "his" mate's offspring on the hope they are his. (And yet another evolutionary adaptation comes into play, the tendency of newborns to resemble their fathers more than their mothers, to forestall their murder by a father unconvinced of his paternity.)

    Which brings us back to the female preference, when fertile, for masculine men. Because that's only one side of the coin: when not fertile, the female actually prefers less masculine men. Now if it's preferable have offspring with a masculine man
  • by recharged95 ( 782975 ) on Monday June 28, 2004 @09:27AM (#9550108) Journal
    I remember doing computer simulations with researchers that used this concept 10yrs ago for addiction research *on humans*. Wasn't accurate compared to PET scanning with EEG biofeedback. I guess technologies likely gotten better, but the problem in this [we discovered] was getting a true mesaure of blood flow: it's pretty much a multi-body problem, more of a 6-body problem (blood flow rate, direction, glucose metabolism rate, type of brain matter, etc...). Simulations only go so far since most models represent a biased view (i.e. theory). Funny how it's already difficult and even impossible to solve a typical 3-body problem to the precision these guys are suggesting--I would be interested to see the details on their accuracy/precision criteria.

    In the end, what value does this offer? Sounds like more of the same topic of controlling us lemmings in the long run. Or maybe M$ (heck MSNBC reported it) is looking for a way to persuade the EU...

  • Re:Two things... (Score:4, Informative)

    by Dr_Emory ( 181130 ) on Monday June 28, 2004 @09:31AM (#9550144)
    This is an excellent point, and one of the most challenging problems with fMRI and other "functional neuroimaging" methods. BOLD-fMRI (Blood Oxygen Level Dependent) relies on the fact that oxyhemoglobin is dimagnetic and deoxyhemoglobin is paramagnetic (a very interesting fact that was discovered in the 1950s by no other than Linus Pauling . . .), which means that oxygenated blood can be made to look "brighter" using certain MRI techniqies. The theoretical steps from neuronal activity to BOLD signal are this:

    1. Neurons fire
    2. Transient decrease of blood oxygen in that area due to increased use
    3. Compensatory regional increase in blood flow causes increase in blood oxygen.
    4. Miracle occurs / Change in concentration in oxygen imaged with MRI and bright "blobs" superimposed over structural image.

    Many problems with this technique, and many assumptions that must be made. Just a few:
    1. We assume that there is a consistent time course to these steps. During image processing, the blood oxygen vs. time curve is usually assumed to follow a particular theoretical model all over the brain. Problem is, maybe the compensatory increase in oxygenation is much slower in some areas of the brain than it is in others.
    2. We have very little idea what it means that we see increased or decreased "activity" in an area, particularly when comparing normal and diseased conditions. Perhaps some areas of the brain are "always on" and there is no clear contrast between that condition and a "working" condition, therefore they NEVER appear to be activated by fMRI. Maybe the area of increased activity represents a "downstream effect" of activity in another area? Does increased activity suggest better function (e.g. more blood = gasoline to the engine = higher speed) or worse (less efficient engine = more gasoline to engine = same speed at higher cost).

    Despite these problems, fMRI is damn cool because you really can "see someone think", which is a relatively new scientific development. The technology will get better, and eventually we'll get closer to the actual neurons, in terms of taking pictures of real neuronal activation instead of a blood oxygen proxy four or five physiological steps away. Anyhow, cool stuff.
  • by slimak ( 593319 ) on Monday June 28, 2004 @09:57AM (#9550343)
    On a related note, check out the 9.4 T [uic.edu] (9.4 T link off to side) scanner at UIC. AFAIK it is the largest (in sense of the static -- B0 -- field) system that is capable of imaging a human. Other stronger magnets exist (such as 14 T), but they have much smaller bores that limit the size of the object being imaged to about the size of a mouse. I believe that they have this beast up at field now and are currently building the gradients for it.

    Should be interesting to see what its capable of, and if anyone is willing to go inside (considering the strength)!

  • by nine-times ( 778537 ) <nine.times@gmail.com> on Monday June 28, 2004 @09:59AM (#9550370) Homepage
    This is yet another case of scientists "discovering" what philosophers had known thousands of years ago. A quote from the article:

    "the Platonic metaphor of the mind as a charioteer driving twin horses of reason and emotion is on the right track--except that cognition is a smart pony, and emotion a big elephant."

    The only thing is, this is basically what the Platonic metaphor says- reason is a weak little horse that doesn't do much of anything, and passion is a wild, kicking, biting stallion that moves the whole thing wherever it wants. The pony/elephant distinction doesn't add anything to the metaphor. Don't get me wrong- the technology is neat and all, and the article might have been worth it for news on technology. But 'humans are irrational'? Is that really news to anyone?

  • by orthogonal ( 588627 ) on Monday June 28, 2004 @10:21AM (#9550544) Journal
    I certainly don't need a lab test to know when my period is coming. Just because women apparently conceal from you when they're menstruating that doesn't mean that we don't know.

    Yes, but ovulation is not menstruation (getting one's "period"). Ovulation occurs about fourteen days before menstruation, and the period of fertility is some period of time a up to five days before ovulation and one to two days after ("fertile" days can occur before actual ovulation because sperm can live inside a woman for up to a week).

    While menstruation pretty reliably occurs fourteen days after ovulation, the time between menstruation and the next ovulation tends to vary much more.

    So while your menstruation is pretty obvious, it gives you little idea of when you'll next be fertile.

    And while some women feel a characteristic pain when ovulation occurs ("Mittelschmerz", German for "middle pain"), because of the varying time between menstruation and ovulation and the ability of sperm to live inside the women, it's entirely possible even for that minority of women who experience Mittelschmerz to become pregnant from sex after menstruation but before ovulation and the warning pain of Mittelschmerz.

    You do know what the technical medical term for a woman who relies on the "rhythm method" of contraception is?

    "Mother".
  • by Anonymous Coward on Monday June 28, 2004 @11:08AM (#9550951)
    You can't be sure when you're absolutely not fertile. But I know when I am fertile.

    The fluid is thinner so there is more vaginal secretion. And you really do get more aroused.

    From a woman.

Remember, UNIX spelled backwards is XINU. -- Mt.

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