This is an interesting first submission by a Hacker News participant who joined the community 551 days ago. The core idea in the submitted blog post (by the submitter here) is

"Contrarian anecdotes like these are particularly common

http://news.ycombinator.com/item?id=4076643

http://news.ycombinator.com/item?id=4076066

in medical discussions, even in fairly rational communities like HN. I find this particularly insidious (though the commenters mean no harm), because it can ultimately sway readers from taking advantage of statistically backed evidence for or against medical cures. Most topics aren’t as serious as medicine, but the type of harm done is the same, only on a lesser scale."

The basic problem, as the interesting comments here illustrate, is that human thinking has biases that ratchet discussions in certain directions even if disagreement and debate is vigorous. The general issue of human cognitive biases was well discussed in Keith R. Stanovich's book What Intelligence Tests Miss: The Psychology of Rational Thought.

http://yalepress.yale.edu/yupbooks/book.asp?isbn=97803001646...

http://www.amazon.com/What-Intelligence-Tests-Miss-Psycholog...

The author is an experienced cognitive science researcher and author of a previous book How to Think Straight about Psychology. He writes about aspects of human cognition that are not tapped by IQ tests. He is part of the mainstream of psychology in feeling comfortable with calling what is estimated by IQ tests "intelligence," but he disagrees that there are no other important aspects of human cognition. Rather, Stanovich says, there are many aspects of human cognition that can be summed up as "rationality" that explain why high-IQ people (he would say "intelligent people") do stupid things. Stanovich names a new concept, "dysrationalia," and explores the boundaries of that concept at the beginning of his book. His shows a welcome convergence in the point of view of the best writers on IQ testing, as James R. Flynn's recent book What Is Intelligence? supports these conclusions from a different direction with different evidence.

Stanovich develops a theoretical framework, based on the latest cognitive science, and illustrated by diagrams in his book, of the autonomous mind (rapid problem-solving modules with simple procedures evolutionarily developed or developed by practice), the algorithmic mind (roughly what IQ tests probe, characterized by fluid intelligence), and the reflective mind (habits of thinking and tools for rational cognition). He uses this framework to show how cognition tapped by IQ tests ("intelligence") interacts with various cognitive errors to produce dysrationalia. He describes several kinds of dysrationalia in detailed chapters in his book, referring to cases of human thinkers performing as cognitive misers, which is the default for all human beings, and posing many interesting problems that have been used in research to demonstrate cognitive errors.

For many kinds of errors in cognition, as Stanovich points out with multiple citations to peer-reviewed published research, the performance of high-IQ individuals is no better at all than the performance of low-IQ individuals. The default behavior of being a cognitive miser applies to everyone, as it is strongly selected for by evolution. In some cases, an experimenter can prompt a test subject on effective strategies to minimize cognitive errors, and in some of those cases prompted high-IQ individuals perform better than control groups. Stanovich concludes with dismay in a sentence he writes in bold print: "Intelligent people perform better only when you tell them what to do!"

Stanovich gives you the reader the chance to put your own cognition to the test. Many famous cognitive tests that have been presented to thousands of subjects in dozens of studies are included in the book. Read along, and try those cognitive tests on yourself. Stanovich comments that if the many cognitive tasks found in cognitive research were included in the item content of IQ tests, we would change the rank-ordering of many test-takers, and some persons now called intelligent would be called average, while some other people who are now called average would be called highly intelligent.

Stanovich then goes on to discuss the term "mindware" coined by David Perkins and illustrates two kinds of "mindware" problems. Some--most--people have little knowledge of correct reasoning processes, which Stanovich calls having "mindware gaps," and thus make many errors of reasoning. And most people have quite a lot of "contaminated mindware," ideas and beliefs that lead to repeated irrational behavior. High IQ does nothing to protect thinkers from contaminated mindware. Indeed, some forms of contaminated mindware appeal to high-IQ individuals by the complicated structure of the false belief system. He includes information about a survey of a high-IQ society that found widespread belief in false concepts from pseudoscience among the society members.

Near the end of the book, Stanovich revises his diagram of a cognitive model of the relationship between intelligence and rationality, and mentions the problem of serial associative cognition with focal bias, a form of thinking that requires fluid intelligence but that nonetheless is irrational. So there are some errors of cognition that are not helped at all by higher IQ.

In his last chapter, Stanovich raises the question of how different college admission procedures might be if they explicitly favored rationality, rather than IQ proxies such as high SAT scores, and lists some of social costs of widespread irrationality. He mentions some aspects of sound cognition that are learnable, and I encouraged my teenage son to read that section. He also makes the intriguing observation, "It is an interesting open question, for example, whether race and social class differences on measures of rationality would be found to be as large as those displayed on intelligence tests."

Applying these concepts to my observation of Hacker News discussions after 1309 days since joining the community, I notice that indeed most Hacker News participants (I don't claim to be an exception) enter into discussions supposing that their own comments are rational and based on sound evidence and logic. Discussions of medical treatment issues, the main concern of the submitted blog post, are highly emotional (many of us know of sad examples of close relatives who have suffered from long illnesses or who have died young despite heroic treatment) and thus personal anecdotes have strong saliency in such discussions. The process of rationally evaluating medical treatments is the subject on entire group blogs with daily posts

http://www.sciencebasedmedicine.org/index.php/about-science-...

and has huge implications for public policy. Not only is safe and effective medical treatment and prevention a matter of life and death, it is a matter of hundreds of billions of dollars of personal and tax-subsidized spending around the world, so it is important to get right.

Blog post author and submitter here tylerhobbs suggests disregarding an individual contrary anecdote, or a group of contrary anecdotes, as a response to a general statement about effective treatment or risk reduction established by a scientifically valid

http://norvig.com/experiment-design.html

study. With that suggestion I must agree. Even medical practitioners themselves do have difficulty sticking to the evidence,

http://www.sciencebasedmedicine.org/index.php/how-do-you-fee...

and it doesn't advance the discussion here to bring up a few heart-wrenching personal stories if the weight of the evidence is contrary to the cognitive miser's easy conclusion from such a story.

That said, I see that the submitter here has developed an empirical understanding of what gets us going in a Hacker News discussion. Making a definite statement about what ought to be downvoted works much better in gaining comments and karma than asking an open-ended question about what should be upvoted, and I'm still curious about what kinds of comments most deserve to be upvoted. I'd like to learn from other people's advice on that issue how to promote more rational thinking here and how all of us can learn from one another about evaluating evidence for controversial claims.