Submitted by nerfhammer

Rationalist subreddit

3 nerfhammer 13 November 2012 01:17AM

I'm experimenting with a new rationalist subreddit on reddit.com

Starting with links populated from the planet rationalist data set - to which I've added about 50 new sources in the past few weeks.

Comments (3)

New study on choice blindness in moral positions

73 nerfhammer 20 September 2012 06:14PM

Change blindness is the phenomenon whereby people fail to notice changes in scenery and whatnot if they're not directed to pay attention to it. There are countless videos online demonstrating this effect (one of my favorites here, by Richard Wiseman).

One of the most audacious and famous experiments is known informally as "the door study": an experimenter asks a passerby for directions, but is interrupted by a pair of construction workers carrying an unhinged door, concealing another person whom replaces the experimenter as the door passes. Incredibly, the person giving directions rarely notices they are now talking to a completely different person. This effect was reproduced by Derren Brown on British TV (here's an amateur re-enactment).

Subsequently a pair of Swedish researchers familiar with some sleight-of-hand magic conceived a new twist on this line of research, arguably even more audacious: have participants make a choice and quietly swap that choice with something else. People not only fail to notice the change, but confabulate reasons why they had preferred the counterfeit choice (video here). They called their new paradigm "Choice Blindness".

Just recently the same Swedish researchers published a new study that is even more shocking. Rather than demonstrating choice blindness by having participants choose between two photographs, they demonstrated the same effect with moral propositions. Participants completed a survey asking them to agree or disagree with statements such as "large scale governmental surveillance of e-mail and Internet traffic ought to be forbidden as a means to combat international crime and terrorism". When they reviewed their copy of the survey their responses had been covertly changed, but 69% failed to notice at least one of two changes, and when asked to explain their answers 53% argued in favor of what they falsely believed was their original choice, when they had previously indicated the opposite moral position (study here, video here).

Comments (151)

binomial variance problem

5 nerfhammer 06 April 2012 10:59PM

Found in an old Kahneman & Tversky paper:

There are two programs in a high school. Boys are a majority (65%) in program A, and a minority (45%) in program B. There is an equal number of classes in each of the two programs.

You enter a class at random, and observe that 55% of the students are boys. What is your best guess -- does the class belong to program A or to program B?

Comments (14)

A Poisson process paradox

19 nerfhammer 06 April 2012 05:20AM

From Steven Pinker's latest book:

Suppose you live in a place that has a constant chance of being struck by lightning at any time throughout the year. Suppose that the strikes are random: every day the chance of a strike is the same, and the rate works out to one strike a month. Your house is hit by lightning today, Monday. What is the most likely day for the next bolt to strike your house?

Comments (10)

New cognitive bias articles on wikipedia (update)

82 nerfhammer 09 March 2012 08:13PM

Also conjunction fallacy has been expanded.

(update) background

I started dozens of the cognitive bias articles that are on wikipedia. That was a long time ago. It seems people like these things, so I started adding them again.

I wanted to write a compendium of biases in book form. I didn't know how to get a book published, though.

Anyway, enjoy.

Comments (19)

Ambiguity in cognitive bias names; a refresher

25 nerfhammer 21 February 2012 04:37AM

This came on the nyc list, I thought I would adapt it here.

Cognitive biases have names. That's what makes them memetic. It's easier to think about something that has a name. Though I think the benefits outweigh the costs, there is also the risk of a little Albert: a concept living on after the original research has been found to be much more ambiguous than first realized.

There are many errors that are possible with respect to named ideas, and despite being studied generally scientifically, cognitive biases are no exception. There is no equivalent to cognitive biases as the Académie Française is to French.

Let's describe some. Here they are:

different people in different fields will "discover" virtually the same bias but not be aware of each other and assign it different names. For example, see the Curse of Knowledge which I think George Loewenstein came up with vs. the Historian's Fallacy by David Hackett Fischer, presentist bias, creeping determinism, and probably many others, not all of them scientific. Sometimes researchers in seemingly closely related subfields are remarkably insular to each other.
researchers will use one term predominantly while an offshoot will decide they don't like the name and use a different one. For example the Fundamental Attribution Error has also been called the overattribution effect, the correspondence bias, the attribution bias, and the actor-observer effect. In this case the older term still predominates, and is used in intro textbooks without asterisks. Of the naming errors this is one of the least harmful, since everyone agrees what the FAE is, some just prefer a different name for it.
an author will decide he doesn't like the names of some biases will invent idiosyncratic names of his own. Jonathan Baron has a good textbook on cognitive bias but he uses names of his own invention half the time.
the same term will sometimes have different polysemous meanings. For example the "Zeigarnik Effect" has been used to refer to a memory bias in having a superior recall for unfinished tasks, and the term has also been used to refer to an attentional bias in which unfinished tasks tend intrude on consciousness; almost, but not quite exactly, the same thing. The term "confirmation bias" has several different but related meanings, for example, to seek out confirming information, to notice confirming information, to ask confirming questions, etc. which are not all quite exactly the same thing. The different meanings may have completely different contexts, boundary conditions etc., leading to confusion. Furthermore some of the senses may be at least partially disproven but not necessarily others, for example, the tendency to ask confirming questions has turned out to be more complicated than once thought. You might never know from reading about the attentional Zeigarnik that there is also a memory Zeiganik effect that is conceptually somewhat different. I recall seeing even prominent researchers occasionally making mistakes of this category. Of all the naming ambiguities I think is the most dangerous.
an offshoot of researchers may knowingly use the same term with a conflicting definition. For example "heuristic" in "Heuristics and Biases" versus "Fast and Frugal Heuristics", the latter of which was an intentional reaction to the former. In this case those involved know there is a disagreement in meaning, but those unfamiliar to the topic might be confused.[This is a point of contention which I'm willing to yield on]
the same term may be redefined by researchers who may not aware of each other. There has been more than one paper trying to introduce a bias to call "the disconfirmation effect". But this only happens for really obscure biases.
a bias may have different components which do not have names of their own and/or a bias may overlap partially but not completely with another bias. For instance, hindsight bias has different components one of which has some overlap with the curse of knowledge.
the same bias term will be used as a rough category of experimental effect and also as a singular bias. For example, the term "an actor-observer bias" could refer to any difference in actors and observers, whereas "the actor-observer bias" refers to the Fundamental Attribution Error specifically; the same is true of "an" vs. "the" attribution bias, also referring to the FAE. This could confuse only those who are unfamiliar with the terminology.
sometimes authors have tried to enforce strict, distinct meanings for the subterms "bias" vs. "effect" vs. "neglect" vs. "error" or "fallacy"; other times, perhaps more often, these terms are used only by convention. For example the conjunction fallacy vs. the conjunction error, correspondence bias vs. the fundamental attribution error, base rate neglect vs. base rate error. Sometimes the originators of a bias try to use the terminology precisely while later authors citing it aren't as careful. Sometimes even the originators of a bias do not try to choose a subterm carefully. You might suspect what permutation of a term catches on is based on whichever has a better ring to it.