tag:blogger.com,1999:blog-9430835.post8578858264499944954..comments2024-03-27T18:24:19.683-07:00Comments on Steve Sailer: iSteve: I don't get itUnknownnoreply@blogger.comBlogger122125tag:blogger.com,1999:blog-9430835.post-43994431783449464142011-11-18T08:12:55.830-08:002011-11-18T08:12:55.830-08:00Steve,
I just finished Kahneman's book, and s...Steve,<br /><br />I just finished Kahneman's book, and someone pointed me at your discussion (I read it a week or two ago as well, but had forgotten).<br /><br />If you finish the chapter in which Kahneman uses this example, he finishes the chapter with the full explanation of (a) what's wrong with people's thinking here, and (b) what you should do instead.<br /><br />The chapter open had me a little suspicious, having read your review. The chapter end cleared up all my questions, and demonstrated that they are as brilliant as polymath suggests.Aretaehttps://www.blogger.com/profile/15850678936908894274noreply@blogger.comtag:blogger.com,1999:blog-9430835.post-87133384113608415172011-11-13T13:40:56.964-08:002011-11-13T13:40:56.964-08:00" (1) Linda is a bank teller.
(2) Lind..." (1) Linda is a bank teller.<br /> (2) Linda is a bank teller and is active in the feminist movement. <br /><br /> The vast majority—roughly 85 percent—of the people they asked opted for No. 2, even though No. 2 is logically impossible. (If No. 2 is true, so is No. 1.) The human mind is so wedded to stereotypes and so distracted by vivid descriptions that it will seize upon them, even when they defy logic, rather than upon truly relevant facts. Kahneman and Tversky called this logical error the “conjunction fallacy.""<br /><br />As part of pattern recognition the brain fills in the blanks.<br /><br />People read #1 as she is a banker and is NOT active in the feminist movement. <br /><br />As an aside everyone who didn't sterotype got eaten by sabertooths a long time ago, now if only they would have eaten these idiots as well.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-25495451795111584772011-11-12T08:51:14.804-08:002011-11-12T08:51:14.804-08:00More fight<a href="http://walt.foreignpolicy.com/posts/2011/09/25/mearsheimer_responds_to_goldbergs_latest_smear" rel="nofollow">More fight</a>Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-68323828955358238502011-11-11T17:28:53.085-08:002011-11-11T17:28:53.085-08:00Doesn't the answer to the Jack question depend...Doesn't the answer to the Jack question depend on your beliefs about:<br /><br />P(political|lawyer)<br />and<br />P(political|engineer)<br /><br />So...<br /><br />If<br />P(engineer) = 0.3<br />P(political|lawyer) = 0.9<br />P(political|engineer) = 0.1<br /><br />then P(engineer|political) = 0.8<br /><br />The answer to the Linda question is always (A) because condition (B) is a subset of (A) and P(A) >= P(B).Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-12252661687478471252011-11-11T12:40:29.119-08:002011-11-11T12:40:29.119-08:00>Shouldn't Kahneman do a study to figure ou...>Shouldn't Kahneman do a study to figure out why his research results so often get twisted to support conventional wisdom nuggets like Stereotypes Are Always Wrong?<br /><br />Previous to Kahneman,I read Schermer's "The Believing Brain" which goes pretty far in answering your question: belief first, then explanation/rationalization. <br /><br />For me, Stereotypes Are Always Wrong, is not conventional wisdom--it is PC. Vanity Fair is a consumate PC magazine, which explains how they got Kahneman wrong--as Schermer describes, belief (PC) first, then rationalized by altering Kahneman's example. YMMV.<br /><br />ForbesAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-2861542769225606672011-11-11T12:07:38.484-08:002011-11-11T12:07:38.484-08:00Shouldn't Kahneman do a study to figure out wh...Shouldn't Kahneman do a study to figure out why his research results so often get twisted to support conventional wisdom nuggets like Stereotypes Are Always Wrong?Steve Sailerhttps://www.blogger.com/profile/11920109042402850214noreply@blogger.comtag:blogger.com,1999:blog-9430835.post-62036496376021952482011-11-11T10:50:12.666-08:002011-11-11T10:50:12.666-08:00Vanity Fair and/or Michael Lewis screwed up/made u...Vanity Fair and/or Michael Lewis screwed up/made up the Jack example. The example is from the appendix of "Thinking, Fast and Slow", as it is, but it is this: <br /><br />"Dick is a 30 year old man. He is married with no children. A man of high ability and high motivation, he promises to be quite successful in his field. He is well liked by his colleagues."<br /><br />As you can see, there are no particular facts or inferences that would influence your judgement regarding Dick's occupation.<br /><br />I am reading the book, and the Vanity Fair exerpt that Steve quoted just sounded wrong. It is.<br /><br />ForbesAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-62836445668191043642011-11-11T09:08:28.436-08:002011-11-11T09:08:28.436-08:00Full disclosure: I am a math Ph.D. whose research ...Full disclosure: I am a math Ph.D. whose research focused on logic and conditional probability, and I work as a professional statistician.<br /><br />Practically all the commenters here are wrong in some way, and nobody has laid a glove on Kahneman himself.<br /><br />The "Jack" experiment involved two separate groups, and the correct conclusion from it is the process the people in the groups used was not sensitive to the prior probabilities in the range between 30/70 and 70/30 splits. However, and counterintuitively, those two sets of prior probabilities are really not very far apart in Bayesian practice, so that I would expect even groups of perfectly logical reasoners to show a difference in posterior probabilities that was small enough to be significantly different from zero only in large experiments; I just bought Kahneman's book, so maybe I will follow up on this and see if the experiments, meta-analytically, were large enough.<br /><br />The "Linda" example, on the other hand, was indeed demonstrating not merely an inconsistency between groups, but an inconsistency in the responses of individuals, because as worded, answer 2 can never be correct and can only be the product of a mathematical, linguistic, or logical error. All the criticisms of Kahneman over this are off base, because they merely explain why people made the mistake, which does not change the importance of the main result, that this particular setup induces people to make mistakes (that really are mistakes, i.e. mental errors, and not simply suboptimal estimation procedures).<br /><br />The kind of interpretive error that most commenters (as well as the idiot Vanity Fair intern, the semi-idiot Gladwell, the semi-brilliant Lewis, and the usually-brilliant Sailer) are making is, ironically, of the same kind being discussed -- the prior probability of Kahneman being correct, given his supreme eminence in the field, is underestimated or misapplied, so that people don't take enough care to check their reasoning when they think they are disagreeing with him.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-84764477103317638892011-11-11T03:02:49.647-08:002011-11-11T03:02:49.647-08:00I wouldn't read too much into the elite aspect...I wouldn't read too much into the elite aspect here. Michael Lewis is in the infotainment elite, and Vanity Fair is in the gossip magazine elite. Their goal was to publish a catchy article that gets noticed (Arts and Letters Daily!). <br /><br />Scientific American is every bit as elite and politically correct as Vanity Fair, but I don't think Scientific American would make a mistake like this. <i>That</i> would be noteworthy. Presumably, though, they care about describing scientific work accurately. I wouldn't expect Michael Lewis and Vanity Fair to stifle their prejudices and get the science right any more than I'd expect that of non-elite people.Aaron in Israelnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-47298926290100327382011-11-11T01:14:08.087-08:002011-11-11T01:14:08.087-08:00"Consider for just a moment that a renowned N...<i>"Consider for just a moment that a renowned Nobel prize-winner might possibly be smarter than you"</i><br /><br />If the guy who pioneered lobotomies/leucotomies got a (medicine) Nobel then I'm sure this Kahneman earned his. We may be fumbling toward something but we're definitely fumbling. I think aforementioned ludic fallacy covers most overclass social-science "research" these days.economists are worsenoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-85475097369381686962011-11-10T22:10:29.991-08:002011-11-10T22:10:29.991-08:00"Given you LOOK at the penny after the toss, ..."Given you LOOK at the penny after the toss, you know the outcome--and so the probability of heads is either 0 or it's 1, but it definitely ain't 1/2."<br /><br />Even undergrads use Laplace smoothing for small samples, but you do not. Nice! I hear in some parts of the universe an MLE does not have an associated confidence interval. Of course, I don't inhabit that part of the universe.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-31173378196382025582011-11-10T22:05:51.751-08:002011-11-10T22:05:51.751-08:00"Lots of people who work with statistics and ..."Lots of people who work with statistics and probability haven't the faintest idea what a probability is saying--even phd level math folks"<br /><br />Every undergrad who has studied Math Stats knows what a probability is. <br /><br />I have yet to meet Phd level Math people, who can grasp measure theoretic probability, who can't grasp something this trivial. Your mistaking your inability to understand what they say for their ignorance. <br /><br />"Given NO OTHER INFO, it's 1/2."<br /><br />Really? There's no reason it can't be 0.99. Since it's an estimation problem, you could (say) find a likelihood estimate after observing a few realizations of the event. More generally, you could construct an approximate confidence interval using the fact that the maximum likelihood estimator is asymptotically efficient.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-67527211077085084252011-11-10T21:46:21.416-08:002011-11-10T21:46:21.416-08:00I'm more interested in anatomizing common elit...I'm more interested in anatomizing common elite misconceptions, since, by definition, they run the world. For example, here you see Kahneman -> Lewis -> Vanity Fair editor (in other words Nobelist to best all around magazine journalist to most expensive magazine) and we still end up with a self-evident mistake. Why? Because everybody knows Stereotypes Are Wrong. So any kind of input triggers that elite response.Steve Sailerhttps://www.blogger.com/profile/11920109042402850214noreply@blogger.comtag:blogger.com,1999:blog-9430835.post-19598712729698827602011-11-10T21:41:09.835-08:002011-11-10T21:41:09.835-08:00If you ask people to estimate what % of the Americ...If you ask people to estimate what % of the American population belong to different ethnic groups, they'll come up with average guesses that add up to way more than 100%.Steve Sailerhttps://www.blogger.com/profile/11920109042402850214noreply@blogger.comtag:blogger.com,1999:blog-9430835.post-25534858059137700082011-11-10T21:20:45.794-08:002011-11-10T21:20:45.794-08:00While Pinker is correct (as paraphrased by Anonymo...While Pinker is correct (as paraphrased by Anonymous) that life isn't a casino, in a straightforward problem like the weather prediction experiment one could on average win money by betting against people's reasoning.<br /><br />Everybody (including Pinker's father) says, yeah, of course we don't think rationally, we all know that. Correct. But that meta-belief often doesn't match our actual beliefs and behavior, which often assume rationality. Our surprise at K and T's findings shows, among other things, how far our actual beliefs diverge from that meta-belief. <br /><br />Even more than that: In the K and T "cold water" experiment where subjects voluntarily chose more pain over less pain (with no external incentive), some subjects even said at the time something like, "This is really weird that I'm choosing this option." <i>They knew that they were acting "irrationally" at the time</i>, contrary to how they'd expect themselves to act, and they were puzzled by it.<br /><br />Pinker (paraphrased) also discounts K and T's work when he suggests that it's just "people are irrational" - hey, we already know that! But did we already know that our actual degree-of-belief function is often superadditive? That's what Tversky claimed to show with the "Linda" <i>and</i> other experiments. If he was correct (I have no idea whether he was), then wouldn't that be a useful contribution to cognitive science? K and T didn't just show that people are irrational (duh), they showed <i>how</i> people are irrational.Aaron in Israelnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-66249700283539568712011-11-10T21:19:05.013-08:002011-11-10T21:19:05.013-08:00Many of the objections to the "Linda" ex...Many of the objections to the "Linda" experiment seem reasonable, especially given the information provided in the article, but they don't apply to the similar experiment where people assigned probabilities to temperature intervals in San Francisco. That experiment did not involve fictional characters, stories, or yanking people's chain. It asked people to assign probabilities to basically value-neutral physical events. Those who object to the "Linda" experiment should address the "weather" experiment where the objectionable features are absent.<br /><br />According to Tversky, both experiments supported the same hypothesis: that as people "unpack" a problem they assign "too much" weight to the components as compared to the whole (i.e., their degrees of belief are superadditive).Aaron in Israelnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-10808051719263736742011-11-10T20:57:32.200-08:002011-11-10T20:57:32.200-08:00Nassim Nicholas Taleb calls this sort of use of pr...Nassim Nicholas Taleb calls this sort of use of probability (including and especially the "Linda" chestnut from Statistics 101) engaging in the "ludic fallacy". While real probability and statistics are a useful tool (and lucky are those who can wrap their minds around the counterintuitive way of thinking required), sometimes we need to be like NNT's streetwise "Fat Tony". When faced with two throws of six dice, one coming up all sixes, the other (in this order) 4, 2, 1, 6, 5, 3, when which being the more likely (given fair dice, under the laws of probability, both throws are equally probable), people not trained in probability would when asked say that the second throw was more likely, because they interpret that precise throw as meaning "random". Fat Tony would agree, but only because he would be skeptical of the fair dice assumption. Call it "metaprobability", i.e. the probability of probability. So when asked about the odds about Linda being both a bank teller and a feminist, they are relying on the same tried and true evolved heuristics that allow me to conclude with confidence that someone who has black table napkins also has black bedsheets. And the reason this heuristic has evolved is that attributes tend to cluster, or, putting it another way: "people are more typical than you can possibly imagine".normannhttps://www.blogger.com/profile/17358715755873851074noreply@blogger.comtag:blogger.com,1999:blog-9430835.post-87607441917002532382011-11-10T20:24:12.891-08:002011-11-10T20:24:12.891-08:00Candid observer has it right. This was a between-g...Candid observer has it right. This was a between-groups study and the point was base-rate neglect. This has been demonstrated umpteen times, using many different approaches. The original K&T is just an initial demonstration of the phenomenon. If both groups provide identical estimates, its reasonable to infer that on average they are not being swayed by the percentages (as Bayes theorem says they should).nsamnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-25114461602234881342011-11-10T20:15:55.683-08:002011-11-10T20:15:55.683-08:00My guess is this is a failure to understand probab...My guess is this is a failure to understand probability. Whether Lewis makes the error, or Kahneman, or the author of the sidebar did, or some editor, I can't tell.<br /><br />Someone in this chain is not a Bayesian.<br /><br />Lots of people who work with statistics and probability haven't the faintest idea what a probability is saying--even phd level math folks. They get themselves all confused thinking about frequencies, outcomes, and having been told false things about independence and then pre knowledge and post knowledge.<br /><br />A probability is a measure of YOUR IGNORANCE. What's the probability you toss a penny and it comes up heads? Given NO OTHER INFO, it's 1/2. Now, say you tossed that penny with a special penny tossing machine that provided just the right impulse, rotation, and adjusted for wind velocity, it might be 99%. Given you LOOK at the penny after the toss, you know the outcome--and so the probability of heads is either 0 or it's 1, but it definitely ain't 1/2.<br /><br />That means that a probability is not "in the world", constant for a given problem as defined, waiting to be found. It depends entirely on what you know, and how well you know it.<br /><br />People have been misled into thinking that knowing more doesn't change a probability by being mistakenly told that "The probability of having a boy baby on a couple's 6th pregnancy when the first 5 are boys is 1/2."<br /><br />That's false--the 5 boys are telling us a great deal about how nonrandom the sex selection is in this case. But people have been told the answer's 1/2, so they apply other mistaken ideas about how evidence changes probabilities everywhere they look.<br /><br />Of course the probability of Jack being an engineer is higher than 30%. It was exactly 30% before you knew ANYTHING except that 30 of the 100 people were engineers. As soon as you were told any more info, the probability changed. Just hearing that it was a man should have changed your probability towards engineer. Certainly the other details should have too.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-79353829987934944162011-11-10T20:02:02.420-08:002011-11-10T20:02:02.420-08:00I seem to remember that Pinker pretty thoroughly d...I seem to remember that Pinker pretty thoroughly demolished this type of thinking, in "How The Mind Works". He basically said that these two psychologists were over-educated versions of smart-ass adolescents. He said that he tried to make a similar type of argument to his father when he was 13 regarding weather fronts, but ended the narrative by saying that long suffering dad was right and his know it all son was wrong. He basically said that Kahneman and Tversky were comparing the real world to a casino, whereas in actuality, the casino is the exception to the real world. The real world is probabilistically different.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-23594568476482560582011-11-10T19:15:26.996-08:002011-11-10T19:15:26.996-08:00This sums up the confusion - essentially probabili...This sums up the confusion - essentially probabilities properly understood measure one's ability to guess. So long as causality abides, probabilities do not exist in 'things' - the objective probability of me winning a lottery is 100% or 0%. The subjective probability is my ability to make an accurate prediction -which would be 1/tickets sold. If I know the lottery is rigged, the subjective probability changes regardless of tickets sold. Same with a die roll. The objective prob. of me rolling a 6 is 100% or 0% as it is determined by physics. My ability to make an accurate guess is 1/6. This changes with more information about the die. If I suspect it is loaded, my subjective prob will not be 1/6. Check out this article:<br /><br />http://mises.org/daily/4979Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-76573097635804683272011-11-10T19:08:20.417-08:002011-11-10T19:08:20.417-08:00The only conclusion you can logically deduce form ...<i>The only conclusion you can logically deduce form the information supplied by by K @ T is that 30% are engineers. Any other conclusion is not necessarily illogical, but it's based on additional information not supplied by K @ T. </i><br /><br />EVERY conclusion we draw relies "on additional information not supplied by K @ T", like the meanings of the words they used.ben tillmannoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-90263065447759147732011-11-10T19:02:33.975-08:002011-11-10T19:02:33.975-08:00Boy, not many commenters seem to have gotten what&...Boy, not many commenters seem to have gotten what's going on in these examples.<br /><br />As Billy Willy points out, the lawyer/engineer example actually does ultimately derive from Kahneman (or K and Tversky). But the actual experiment they performed was decidedly different from what is suggested by the Vanity Fair sidebar.<br /><br />Again, TWO groups of subjects were presented with very DIFFERENT prior probabilities as to the proportion of lawyers and engineers. Yet, apparently, they came up with essentially the SAME posterior probabilities. The only reasonable conclusion to draw is that, on average, as a group, these subjects simply dismissed the prior probabilities. <br /><br />There may be some issues as to whether the subjects of this sort of question and others "really" understood what was being asked, and the exact meaning of what was being assumed, but in a way that's the point: people DON'T focus on these things in such a fashion as to pull out the essential ingredients relevant to logical inference. Instead, they simply think about subject matter in a sloppy, stereotyped way. If, upon thinking about certain issues, they effectively ignore prior probabilities, or the significance of conjuncts, then they are thinking in some way other than a logical one. <br /><br />That is what is important to recognize in people, to explain, and to incorporate into one's theories about human behavior.candid observernoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-81048296065457523182011-11-10T18:10:18.089-08:002011-11-10T18:10:18.089-08:00I know it's the exception that proves the rule...<i>I know it's the exception that proves the rule - so I'm still waiting to find the lawyer that enjoys or even practices home carpentry.</i><br /><br />Here's one. I enjoy it, but I don't do it because I enjoy it -- I do it because it needs to be done.ben tillmannoreply@blogger.comtag:blogger.com,1999:blog-9430835.post-47308803017790758112011-11-10T17:20:31.963-08:002011-11-10T17:20:31.963-08:00@ anon -"John got passed over in promotion to...@ anon -"John got passed over in promotion to less qualified workers, has been denounced as a 'racist' for discussing racial differences, has been called a 'xenophobe' for expressing negative views on open immigration, has been denounced as a 'homophobe' for opposing gay marriage. <br /><br />What is the chance that he's a white conservative?"<br /><br />Not 100%, that is for sure. :)Luke Leahttps://www.blogger.com/profile/11290760894780619646noreply@blogger.com