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Thread: Social Contagion theory

  1. #1
    Council Member Rob Thornton's Avatar
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    Default Social Contagion theory

    I was hoping some of learned folks might share some thoughts on Social Contagion. I've been listening to Daniel Goleman's book Social Intelligence on the drive and he's pitched some pretty interesting ideas that I think are relevant to the way terrorism is used - particularly in the way it has been used in Baghdad.

    When the violence seems to defy all reason and logic, when its physics resemble that of a large scale wild fire, how do you contain and manage it. Goleman makes a good case for the theory, and is able to bring in some hard science in the relatively new ways scientists are experimenting on brain cells. I just wanted to see if any of us had considered this theory and what their thoughts are.

    Regards, Rob

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    Council Member Dominique R. Poirier's Avatar
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    Mr. Thornton,
    I willingly subscribe to your visible efforts to find solutions, but with all regards to it I have the sentiment that venturing on this way might turn out to be misleading at some point.

    The basis sustaining the previous opinion is fifteen years of professional experience in communication, advertising, and media and substantial personal studies on social sciences. No offense.

    Sincerly,
    Last edited by Dominique R. Poirier; 06-30-2007 at 10:22 PM.

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    Council Member Rob Thornton's Avatar
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    Dominique,
    None taken. Just looking for causal reltionships & how certain theories in human behavior in one area might be used in another.
    Best Regards Rob

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    Council Member slapout9's Avatar
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    Rob, one of the examples was employees in a hospital setting. I can tell you from personal experience as recently as last week that there is something to this theory. If certain key players are behind a project it can be amazing how it spreads from person to person. Both for it and against it. I am going to have to get that CD. Could you expand on this theory a little more. I also experienced this alot in LE especially with gangs or crime families.

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    Council Member Dominique R. Poirier's Avatar
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    Quote Originally Posted by slapout9 View Post
    Rob, one of the examples was employees in a hospital setting. I can tell you from personal experience as recently as last week that there is something to this theory. If certain key players are behind a project it can be amazing how it spreads from person to person. Both for it and against it. I am going to have to get that CD. Could you expand on this theory a little more. I also experienced this alot in LE especially with gangs or crime families.
    I acknowledge I have not been that explicit on my previous advice.

    Sorry.

    Actually, it would claim quite a long comment to make my point perfectly clear and that’s why I didn’t do it.

    Wholesome, you start today with this “Social Intelligence,” and you’ll be immersed into existentialism tomorrow. In the meantime you’ll have wasted some of your time reading Pierre Bourdieu, of course. Holly cow; I did waste mine with it! But I had the excuse to be young, at least.

    I am sorry to be that offhand in my way of expressing myself this time, but wake up! Or, one day you’ll end dressing psychedelic style, smoking marijuana, and playing tam-tam during anti-war protests.

    I insist, no offense. But better warning you and taking the risk to be upsetting than to passively let you engaging in such fairy tales.

    The only way I see to make profitable use of that kind of stuff is, at best, relevant to psyop applied to Northern hemisphere countries. But that is another story…

    Sincerely,

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    Council Member Rob Thornton's Avatar
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    Dominique,
    You'll have to get to used to what we do here - most of us are professionals in our own right and as such have formed opinions about what might or might not be useful. We may start with one thing and by the end of the thread wind up somewhere very different. We generally are inclusive, and open. We are also fairly good analysts about applicability of a topic or theory. You are certainly welcome to chime in and provide your view; in fact that is what makes the site good. However, please don't expect that we will simply drop a subject we are interested in, unless you offer a compelling counter-theory to explain the topic at hand - in which case the initial subject served its purpose.
    And please call me Rob, I don't use a pseudonym for a reason - Mr. Thornton sounds much too formal for continued discussion

  7. #7
    Council Member Dominique R. Poirier's Avatar
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    Default Roger...

    All right, Rob. I'll do my best to go by the book, next time.

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    Council Member Rob Thornton's Avatar
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    Slapout,
    The author's first book was on emotional intelligence (in fact that was the name) - I have not read that one, but he spends some time going over it where needed. This idea of a contagion is based on how mirror neurons work. The author also breaks down how the senses tie in "low road" and "high road" emotive cognition. Empathy it seems has several definitions.

    Consider how panic works. It is primarily a base or low road response with little rationalizing behind it. It seems our brains have evolved to pick up on warnings and other emotions - we are somewhat wired for survival. The author also points to experimentation which points to us being wired for social activity. Combining the two means that strong emotions may trigger instincts - the whole "flight or fight" pitch. The emotion of the situation dampens rational thought - particularly when the object at risk might be yours or your family's life. Further, he suggests that ay rationalizing (high road functions) that occurs is subject to mutation by the "low road".

    Part of this is the type of chemical reactions that occur. Remember the info that somebody was recently experimenting with fear inhibitors for military use. Anyway this is not a technology pitch

    I agree there has to be something to the idea. Something happens when you have cult murders, infanticide, tribal genocide, riots, and indiscriminate killing like that of Baghdad last year.

    So how does understanding help? The causal relationship does not disappear quickly. You can't frontal lobotomize populations. What it might help us do though is anticipate reactions to events or guage how crowd behavior goes South. This might be applicable to population control type tasks or operations, or deconstructing where things went bad. It might also be useful be useful in looking at constructing ROE measure that keep someting from going critical.

    Is Marc T around - I hate to always reach for Marc to provide us info on social sciences, but we're still looking for some other scientists to fill the roles of us knuckle draggers and Serpicos

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    Council Member slapout9's Avatar
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    Rob, thanks for the information. With a longer explanation I definitely think there is something to this particularly with the crowd type situations you have mentioned. To give you a current example that has been in the news lately about gangs is the "Don't Snitch campaigns" that are catching on all across the country. Gangs are promoting a don't snitch or cooperate with the Police and this was a grass roots campaign that has flat out caught fire. Most recently one girl had snitch "Branded" on her forehead when she gave the police some information about a murder. Is the CD better or should I get the book?

    Dominique: Thanks for you concern but somehow I don't think you need to worry about me dressing like a Hippie,smoking dope and betting a drum at the next anti war rally.

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    Council Member Rob Thornton's Avatar
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    Wow, can you treat "branded" as a hate crime as well? I got the CD from the Carlisle library as I have a 30 minute drive to/fro - Its about 11 CDs I think, but if you are already doing a lot of reading it might be a nice change. The only thing I don't like about books on tape is that they make using citations harder

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    Council Member slapout9's Avatar
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    Rob, I don't know if it can be considered a hate crime or not. Usually that involves one race against another, in this case they were all the same race. I think the suspect is part of the Dark Triad you talk about on your other thread. I might have to try the CD approach haven't done that yet.

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    Council Member marct's Avatar
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    Hi Rob,

    Quote Originally Posted by Rob Thornton View Post
    Is Marc T around - I hate to always reach for Marc to provide us info on social sciences, but we're still looking for some other scientists to fill the roles of us knuckle draggers and Serpicos
    Just trying to take off most of the Canada Day weekend (lots of strawberry daiquiris yesterday ).

    I've used various forms of social contagion theories (note the plural). One of the earliest I found was by psychologist Mark Baldwin from the 1890's, although there are inferences towards this type of theory in the works of Quetelet and Babbage from the 1830's. Modern versions include the one you referred to, as well as some interesting stuff in criminology (cf Mark Hamm on skinhead gangs - the reference eludes me, we were drinking too much beer at the time), some of the work of Dawkins on mind viruses, and, of course, Barry Wellman's stuff along with his circle.

    On the whole, I have found that the general "shape" (?) of the theories are rather poorly defined - they rely either on structures (e.g. social network analysis) or on content (e.g. mind viruses). Few of them seem to try and integrate the two, although Piere Bourdieu's work tries in some ways. BTW, Dominique is scathingly accurate in how Bourdieu can rot the mind - although a good solid reading of Malinowski acts as an antidote (cf. Argnaughts of the Western Pacific). Bourdieu "borrowed" many of his ideas from Malinowski .

    To my mind, the major problem with social contagion theory is that it is at a very early stage of its development - sort of the "humours" stage of medicine. We don't really have the technology to perceive most of the content beyond inference, and our understandings of the structures involved are, really, quite minimal. Sure, we know a lot about social networks and kinship networks, but how about the mechanism of transmission between people of an "idea" or "perception"? When it's a highly stylized and formalized transmission, sure, we know some of the mechanisms - this is, after all, what ritual is all about. Even there, and it's the one I know best, we are still working off of incomplete observational data. For example, to really understand the process, we would need to be able to actually monitor neuronal change (along with neurotransmitter changes) in real time without interfering with the actual operation.

    Rob, remember a while ago when I was arguing that the real CoG of AQ was the technological ability to transform the Love of God into hatred of the West? This is the sort of thing I was trying to get at - a technology for transforming the content perceptions of individuals and then transmitting them to the "open ideas"marketplace.

    Marc
    Sic Bisquitus Disintegrat...
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    Institute of Interdisciplinary Studies,
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    The Canadian Centre for Intelligence and Security Studies, NPSIA
    Carleton University
    http://marctyrrell.com/

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    Default An American example

    People interested in this topic might like to read the chapter called "The Great Fear" in David Hackett Fischer's book Paul Revere's Ride:

    http://www.amazon.com/Paul-Reveres-D.../dp/0195098315

    Fischer describes in considerable detail the (now forgotten) panic that swept through the Massachusetts civilian population left behind on the morning of 19 April 1775 as the local militia companies from each town marched to Concord.

    After the men were gone these individual emotions flowed into one another like little streams into a river of fear that flooded the rural towns of Massachusetts. On a smaller scale, it was not unlike the grande peur that swept across the French countryside in 1789, when ordinary people were suddenly consumed with a sense of desperate danger....

    On the North Shore of Massachusetts, there was a special panic called the "Ipswich fright." A report spread through Essex County that British soldiers had come ashore in the Ipswich River and were murdering the population of that town. The rumor traveled at lightning speed up and down the coast. It was written that "all the horses and vehicles in the town were put in requisition: men, women, and children hurried as for life toward the north. Large numbers crossed the Merrimack, and spent the night in deserted houses of Salisbury, whose inhabitants, stricken by the strange terror, had fled into New Hampshire....

    The great fear also spread to Loyalists in Boston and even to the Regulars themselves. Admiral Samuel Graves later remembered a wave of hysteria swept through the British troops who were suddenly conscious that they were in "the neighborhood of so enraged an host of people, breathing revenge for their slaughtered countrymen...."

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    Council Member Dominique R. Poirier's Avatar
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    Quote Originally Posted by Rob Thornton View Post
    Dominique,
    (.....) please don't expect that we will simply drop a subject we are interested in, unless you offer a compelling counter-theory to explain the topic at hand - in which case the initial subject served its purpose.
    Rob,
    I apologize once more for my way of expressing my opinion about this subject. Also, in an afterthought, I considered that it was worthwhile to argument my point as you suggested it, even though it would make a long comment, as I surmised.

    So, all I am going to say relies mostly on a personal experience in communication during which I had been concerned at some point with similar, say, “things.”

    First of all, my reader has to accept a notion which says that scientists, and even respected scientists sometimes, may be fooled in the very frame of their specialty. For, no matter how smart and educated we are, the diploma we may have in our pocket, the name of the university in which we teach; we are human and, as such, we are subject to credulity, self-delusion, vanity, ambition, bellow-the-line mental impairment, and influence.

    There is a long record of reputed scientist who succumbed to these weaknesses. Many believed or still believe in the existence of extraterrestrial visits on earth aboard flying saucers. Others feel personally compelled in particular forms of ideology or irrational beliefs. Others are just dishonest and do not hesitate to fool others either in order to prove the validity of what they sincerely believe in, or in order to collect others’ interest, or even sometimes in order to get money or to obtain subsides to finance their researches.

    In most instances those “flawed” scholars and scientists act thus way in total independence and for very personal reasons. They are not at all acting in the frame of a conspiracy or else.

    We are dealing here with cognitive consistency and interaction between theory and data. Consistency can largely be understood in terms of the strong tendency or people to see what they want to see and to assimilate incoming information to pre-existing images.

    So, it happens sometimes that one of those persons fancying sulfurous theory successfully collects the interest of quite down-to-earth organizations which, truly, do not subscribe to their theories. For, their prestigious and credible credentials, and the prestige of their reputation or this of the university or research centre or which they work, added to the hazardous theories in which they personally venture, may serve other particular aims and goals.
    In other words, certain hardly verifiable theories and assumptions may get much credit, or at least interest, when proposed, advocated, and promoted by famous or respectable persons. I am talking about what we use to call “influence.”

    Since we are not intellectually omnipotent, how to make the difference between serious scientific theories and works worthy to collect our interest and scientific disinformation?

    To draw inferences from ambiguous information, one must employ less certain intellectual tools. The question to ask of these ways of thinking are whether they yield perceptions that are as accurate as those that would be produced by other processes and, at minimum, whether they are rational. This is particularly tricky when attempting to draw inferences from scientific data which, by its diversity of fields is likely to put us at some point, if not often, in terra incognita.

    When this occurs, when the advanced theories we are interested in seem hardly questionable for want of a suited scientific knowledge, we have to rely on other considerations.

    Personally, when facing such challenge, I turn, first, to syntax and semantic analysis in the aim to find patterns likely to betray a possible slight mental unbalance, or to spot the presence of too elliptic phrases and statements and their frequency. Often, scientists and authors attempting to fool others or to “honestly” convince others “trick” the content of their essay through the over use of prestigious names and quotations which sustain points and assumption that, truly, hardly connect each with others while we are dedicating much of our attention to it. An essay containing prestigious names and quotations pertaining to too many and a priori unrelated scientific fields betrays an unscientific way of doing things and so it is highly suspect.
    Most good and serious scientists manage to make their point clear and sustain their statements with citations and names.

    Moreover, further inquiries about names and citations are pretty useful and will provide us with a precious knowledge on the foundations sustaining the works and assumptions of the author who is the object of our scrutiny. It will tell us whether these parts or the near totality of this scientific background is likely to be scientifically obsolete, or even ideologically or politically biased, for example.

    But, balanced structures do not necessarily reveals irrationality if the cognitive consistency of a given scientist or author can be explained by his well grounded beliefs about the consistency existing in the environment he is perceiving; and so an author or a scientist may be sometimes honest and wrong at the same time.

    Because many of the structures in the world are balanced, the tendency to perceive balance often serves people well. It may, of course, lead people astray when the stimuli do not fit the pattern. As example picturing this last point, though it is not relevant to scientific matters, this is one reason why American decision-makers were slow to recognize that two of their enemies (Soviet Union and China) were hostile to each other.

    When I said rational I meant those ways of interpreting evidence that conform to the generally accepted rules of drawing inferences. Conversely, irrational methods and influences violate these rules of the “scientific method” and would be rejected by the person if he were aware of employing them.

    We should not deduce from the observation of inconsistencies that the scientist or the author which is under our scrutiny is necessarily dishonest. For, when cognitions are organized to produce irrational consistency, choice are easier since all considerations are seen as pointing to the same conclusion. Nothing has to be sacrificed. But since the real world is not as benign as these perceptions, values are indeed sacrificed and important choices are made, only they are made inadvertently. As I said earlier, most scientists and authors who are advocating a disputable theory or thesis do it with authentic sincerity.

    As I previously said, some of those scientists and authors venturing into hard-to-prove or disputable speculations are sometimes the target of organization truly looking for misinformation and disinformation operations done either in order to implicitly sustain or challenge political or religious ideologies or other scientific theory, or to help arouse doubt in other’s mind, or to confuse other’s mind (i.e. those of an opponent), or to “pollute” their mind with irrelevant information or “noise.” These practices belong to the realm of information warfare, or psychology warfare.

    While it is important to consider separately the reliability of the source, as indicated by previous records, and the inherent credibility of the message, as indicated by its compatibility with other evidences, the final judgment should rest on an evaluation of both factors.

    As conclusion to this long post I sustain my point with some examples.

    Sigmund Freud’s assumptions and theory sustained left-leaning inclinations, even though this famous scientist would certainly retort that his works and discoveries sustained on the contrary the validity of socialism as best solution to general discontent. However, Freud happen to be right about many things that do not relate to political or ideological considerations.

    Jean Emile Charon, a French nuclear physicist, conducted nuclear research at France’s Commissariat à l’Energie Atomique (Atomic Energy Commission). At some point of his career, this reputed scientist crossed the limits defined by the whole scientific community when he attempted to unify in a same theory—he named theory of “complex relativity”—quantum mechanics and a sulfurous perception of the human mind. He published several books filled with challenging mathematic and physics formula of his own which all demonstrated the existence of a sub particle he called “electron-eon.”

    From time to time, we all hear about archeologists who deliberately burry authentic archeological items, previously found elsewhere, in the ground of an archeological site in order to demonstrate the validity of their theory.

    Alan David Sokal is a professor of physics and faculty member of the mathematics department at New York University. He received his Ph.D. from Princeton University in 1981. In January 2006, he was appointed as the Chair of Statistical Mechanics & Combinatorics at University College London. Curious to see whether a prestigious scientic publication would publish a submission which "flattered the editors' ideological preconceptions", Sokal submitted for publication a grand-sounding, but nonsensical paper entitled "Transgressing the Boundaries: Towards a Transformative Hermeneutics of Quantum Gravity". The journal did publish it, and Sokal then revealed the hoax, so as to prove how easily the most qualified and most competent scientist can be abused by titles and challenging essay sparkled with serious and unquestionable quotations.
    Last edited by Dominique R. Poirier; 07-05-2007 at 02:05 PM.

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    Council Member Rob Thornton's Avatar
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    Smile Its all good

    Dominique,
    No need to apologize. I just wanted everyone to know that much of the value in this site comes from diverse conversations and views. Sometimes we will take something (a thought or perspective) and extract a new angle from what it engendered in its original context - it just helps us think. Understanding that something's original context is also very helpful and may steer us to something better - I beleive that is all you were trying to do.

    Your thoughts are appreciated and helpful, and I'm very glad you are participating. Can't write more now as I'm taking the family to see the Liberty Bell.

    Best regards, Rob

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    Council Member marct's Avatar
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    Hi Dominque and Rob,

    It is a good point to remember that we can get locked into our mindsets .

    Dominique, I assign the Sokal papers to my students as an example of this. As a note, the idea of combining "consciousness" with quantum mechanics has been fairly popular, at least in some crowds (e.g. Dennet, Penrose), since the early 1990's. On the plus side, they were attempting to define, as part of that debate, exactly how you would go about testing such a theory. The discovery of quantum gate structures in neuronal cells in 1995 (I think - can't remember the reference of the top of my head) does actually give a potential physical basis for it.

    Marc
    Sic Bisquitus Disintegrat...
    Marc W.D. Tyrrell, Ph.D.
    Institute of Interdisciplinary Studies,
    Senior Research Fellow,
    The Canadian Centre for Intelligence and Security Studies, NPSIA
    Carleton University
    http://marctyrrell.com/

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    Council Member Nat Wilcox's Avatar
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    Default I don't know social contagion theory,

    but there is (what seems to be) a related collection of theories of imitative behavior, "herding" and so forth in decision and game theory, plus an experimental literature that looks at it.

    You can think of imitation as something a reasonable person 3 might do when only weakly informed themselves, even when their own weak information considered alone recommends non-imitation. Suppose person 3 has weak information favoring action Y over action X. But person 3 also observes that persons 1 and 2 have chosen to take action X rather than Y. Suppose also that person 3 believes that her own information is no better than that of persons 1 and 2, and also believes that her own values and/or goals are not very different from those of persons 1 and 2. Then it may be reasonable for her to completely ignore her own information, and imitate persons 1 and 2.

    Now, let person 4 show up, also in the same situation as person 3 was. He sees three people taking action X over Y. And so he too ignores his own information. And so forth. Decisions "herd together" and it becomes reasonable for all subsequent weakly informed decision makers to ignore their own information. Fittingly, the theorists call this an "information cascade."

    Interestingly, "reverse cascades" can form when everyone receives only noisy and weak information...these are cascades where everyone takes the "wrong" decision..."wrong" in the sense that, if there was some alternative way to pool everyone's (individually ignored) information publicly, it would be clear that everyone had been fooled into herding on the wrong decision.

    As I mentioned, there is some experimental literature on information cascades if anyone is interested in them. I suspect that, for the purposes of this group, information cascades and other kinds of "reasonable herding" are most useful as an idea to keep in mind--simply, that there may be "good reasons" for any actor in a social network to imitate or herd, so that it may be a difficult thing to fight or alter.

    It also suggests that one way to break cascades and herds is to supply alternatives to inferring information from the observation of decisions...alternatives that allow for all individuals' weak bits of information to be combined publicly. The whole problem with cascades is that once enough decisions line up so that people ignore their own information in making their own decision, future decisions become uninformative.
    Last edited by Nat Wilcox; 07-05-2007 at 09:20 PM. Reason: little errors...whoops

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    Council Member Dominique R. Poirier's Avatar
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    Quote Originally Posted by marct View Post
    Hi Dominque and Rob,

    It is a good point to remember that we can get locked into our mindsets .

    Dominique, I assign the Sokal papers to my students as an example of this. As a note, the idea of combining "consciousness" with quantum mechanics has been fairly popular, at least in some crowds (e.g. Dennet, Penrose), since the early 1990's. On the plus side, they were attempting to define, as part of that debate, exactly how you would go about testing such a theory. The discovery of quantum gate structures in neuronal cells in 1995 (I think - can't remember the reference of the top of my head) does actually give a potential physical basis for it.

    Marc
    Marc,
    I have been interested in quantum mechanics during close to a couple of years circa the early 90’s and I have to acknowledge, in the defense of those who lost ground at some point, that your landmarks may be seriously challenged when you comes at last to understand that the mass of a particle is expressed in energy units, and that mass, as the profane understands it at a macroscopic level, has no longer relevance in the realm of microcosm. You come to realize that everything around us, and us including, is all about energy. From this standpoint on I think that the leap toward irrationality is a small one and is easy to do.

    As a matter of fact, and still talking about cognitive bias, I remember some interesting conversations I have had about the opportunities that could be found in the fairly rational mass/energy equivalence as a way of getting people into any imaginary world that would please to you (ex. spiritualism and ghosts, telekinesis, telepathy, nihilism, etc.)

    I guess I won’t teach you anything in saying that, as science, quantum mechanics has the exceptional particularity to have regularly allowed accurate predictions of physical events without previous testing and with mere theory and calculations as sole information available--the prediction of the existence of the quark and of its exact number per particle, if I may describe things that way, is one among the best examples.
    Although it is not relevant to quantum mechanics the theory of general relativity equally relates to this exceptional specificity and it is even a better example since it is more popularly known.

    So, quantum mechanics constitutes both a nice example and a nice opportunity for whosoever is looking for a sound fulcrum in order to fool others’ mind.

    There would be a thick book to write about the matter. Isn’t it?

    Regards,

  19. #19
    Council Member Dominique R. Poirier's Avatar
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    Quote Originally Posted by Nat Wilcox View Post
    but there is (what seems to be) a related collection of theories of imitative behavior, "herding" and so forth in decision and game theory, plus an experimental literature that looks at it.

    You can think of imitation as something a reasonable person 3 might do when only weakly informed themselves, even when their own weak information considered alone recommends non-imitation. Suppose person 3 has weak information favoring action Y over action X. But person 3 also observes that persons 1 and 2 have chosen to take action X rather than Y. Suppose also that person 3 believes that her own information is no better than that of persons 1 and 2, and also believes that her own values and/or goals are not very different from those of persons 1 and 2. Then it may be reasonable for her to completely ignore her own information, and imitate persons 1 and 2.

    Now, let person 4 show up, also in the same situation as person 3 was. He sees three people taking action X over Y. And so he too ignores his own information. And so forth. Decisions "herd together" and it becomes reasonable for all subsequent weakly informed decision makers to ignore their own information. Fittingly, the theorists call this an "information cascade."

    Interestingly, "reverse cascades" can form when everyone receives only noisy and weak information...these are cascades where everyone takes the "wrong" decision..."wrong" in the sense that, if there was some alternative way to pool everyone's (individually ignored) information publicly, it would be clear that everyone had been fooled into herding on the wrong decision.

    As I mentioned, there is some experimental literature on information cascades if anyone is interested in them. I suspect that, for the purposes of this group, information cascades and other kinds of "reasonable herding" are most useful as an idea to keep in mind--simply, that there may be "good reasons" for any actor in a social network to imitate or herd, so that it may be a difficult thing to fight or alter.

    It also suggests that one way to break cascades and herds is to supply alternatives to inferring information from the observation of decisions...alternatives that allow for all individuals' weak bits of information to be combined publicly. The whole problem with cascades is that once enough decisions line up so that people ignore their own information in making their own decision, future decisions become uninformative.
    Nat,
    All you say seems to be inspired by observations about stock market. Isn’t that so?

  20. #20
    Council Member Nat Wilcox's Avatar
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    Default Dominique,

    Yes and no. The first theoretical paper I know of did indeed have some finance researchers amongst the coauthors; it's definitely right to say that the statistical logic of cascades partly emerged from thinking about fads, fashions, bubbles and crashes in asset markets. The funny thing, though--as with many such things--is that the formal logic of a cascade doesn't precisely apply to an asset market (or at least, not all of it), so that there is a bit of a disconnect there between the kinds of phenomena that inspired the cascade and their own formal logic.

    The reason for this is that the "discreteness" of the observed decision (the "choose X or Y" scenario I described) in a true cascade is crucial to its logic. In a situation where people observe and choose bids and asks, which are roughly continuous, the person 3 can indeed reveal new information by the bid or ask she submits, although she would of course sensibly pay attention to, and be influenced by, the previously observed offers of persons 1 and 2. But this is a crucial difference, because person 3 (and then person 4, and so on) will continue to reveal new and useful information by their actions. The thing about true information cascade situations that is uniquely interesting, is that there comes a point in them where everyone ceases to act at all on their own information.

    Inferences from others' decisions is a situation where the quantal (or discrete) versus the continuous turns out to be a crucial distinction (theoretically speaking, anyway).

    The Wikipedia entry linked below, as you will see, is a bit internally confused (it first points out the crucialness of the discreteness of the decision to the logic, but then goes on to assert some connection to asset markets where decisions are not discrete). But it has a lot of good links to large bibliographies. You can see in these bibliographies that there have been many applications to technology adoption, voting, etc.

    http://en.wikipedia.org/wiki/Informational_cascade

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