# Talk:Confirmation bias

This science related article has been awarded BRONZE status for quality. It's getting there, but could be better with improvement. See RationalWiki:Article rating for more information.

## Brainstar rating

This article would be worthy of a Brainstar, in my opinion, if it had more in-line citations. Professor Chaos (talk) 12:23, 8 September 2011 (UTC)

Aye. Not necessarily needed for `{{bronze}}` as that just means "coherent content". ADK...I'll envision your glucose! 12:26, 8 September 2011 (UTC)

## 1 more efficient?

How is turning over the 1 card "more efficient" than turning over the A card? Both could potentially reveal a card with a vowel on one side and an odd number on the other side, so they seem to be perfectly equal. --90.179.235.249 (talk) 19:00, 29 June 2012 (UTC)

Because you can disprove the hypothesis with that turn. If you went for the other option first, you'd still need more turns than necessary no matter whether the hypothesis was true or not. pathetic 23:42, 29 June 2012 (UTC)
I can equally disprove it with either card. If I turn over the A card and there is an odd number on the other side, the hypothesis is disproven. If I turn over the 1 card and ther is a vowel on the other side, the hypothesis is disproven. There is no difference between the two.--90.179.235.249 (talk) 21:37, 1 July 2012 (UTC)

Turning over either card has two possible outcomes, one that disproves the theory and one that neither proves or disproves it.

• Turning over the 1 card can either reveal a vowel (disproven) or something else than a vowel (neither proven or disproven).
• Turning over the A card can either reveal an even number (neither proven or disproven) or something else than an even number (disproven).

Both cards are eqiuvalent.--90.179.235.249 (talk) 21:53, 1 July 2012 (UTC)

Where does the article say that turning over the 1 card is more efficient than turning over the A card? What I am reading is that if you flip the 1 card first, then the A card is the best to flip second. ListenerXTalkerX 22:10, 1 July 2012 (UTC)
First, turning over the odd number and viewing a vowel on the other side of that card would invalidate the hypothesis quickly and more efficiently; vowels shouldn't have odd numbers on the back. — Unsigned, by: 90.179.235.249 / talk / contribs
That is not comparing the flipping of the 1 card to the flipping of the A card, but to the flipping of the 2 card. ListenerXTalkerX 22:59, 1 July 2012 (UTC)
It's also contrasting the methodology of falsification vs confirmation. postate 23:18, 1 July 2012 (UTC)
How? Both cards are the same. --90.179.235.249 (talk) 09:57, 2 July 2012 (UTC)
2 is irrelevant. Quickly and more efficiently than what? --90.179.235.249 (talk) 09:57, 2 July 2012 (UTC)
I think the BoN is right here. There are several problems with the disproof paragraph, starting with the implication that you need to turn three cards to proove the hypothesis, when the preceding para has just established you only need two. It then talks about turning over "1" as being more efficient when no other option has yet been introduced, and introduces a pointless order to "1" and "A" when either works fine. I'm not going to change anything while this discussion is ongoing, but it definitely needs changing. rpeh •TCE 10:08, 2 July 2012 (UTC)
(EC)Yes, 2 is irrelevant, but flipping crops up instinctively in the problem (when this has been presented to people) as part of confirmation bias. Because flipping 2 and viewing a vowel will confirm the hypothesis (flipping 2 and seeing something else does nothing). And so when the problem is presented to people in experiments, instinct tends to require 3 flips. If you start from a method of falsification, you need, at most, 2 flips. bomination 10:11, 2 July 2012 (UTC)

## Wason card problem - again

I also don't get this.

The hypothesis is: "If a card has a vowel on one side, then it has an even number on the other side." We are presented with face-up cards A, B, 1, 2 and asked to check the hypothesis.

Why would I care about what is under "1" and "B"? No statement is made about consonants and or odd numbers so why would looking at them demonstrate anything about the hypothesis? Were the statement to be ""If (and only if) a card has a vowel on one side, then it has an even number on the other side." then things would be different. But that is not the claim.--Bob"I think you'll find it's more complicated than that." 12:41, 11 January 2014 (UTC)

Yeah, you're right. Perhaps the original author wasn't trained in formal logic or math, and missed the distinction between "if" and "if and only if"? - GrantC (talk) 16:21, 11 January 2014 (UTC)
Actually, I think I am mistaken. If I turn over the card "1" and there is vowel on the other side then the hypothesis is disproved. But I don't think that this is explained very well. You also still got to turn over the other two cards anyway to really check - so I'm still not sure what it's supposed to be showing.
I think it should be re-written or removed, as it's more likely to confuse than clarify the point.--Bob"I think you'll find it's more complicated than that." 20:34, 11 January 2014 (UTC)
Well the way it's worded as an "if" proposition still doesn't work, I think. If the card is not a vowel, we gain no information, since the proposition doesn't care whether the flip side is even or odd. If the card is an even number, and we flip it over, that still gives us no information, because a result of a B is still meaningless. - GrantC (talk) 20:41, 11 January 2014 (UTC)
Correct me if I'm wrong, but it seems like one needs to flip only the "1" and the "A" over to check the hypothesis as it is currently written. - GrantC (talk) 20:42, 11 January 2014 (UTC)
Never mind, I now see the point you're making. It's poorly written indeed. What I said in my previous comment is correct, and is what the article purports to explain, but I didn't even realize that until after a few times reading it through... - GrantC (talk) 20:44, 11 January 2014 (UTC)
I would suggest that we cut the whole thing from the article and past it here so that others can see what the debate was about.
But let's wait a while unless others want to comment.--Bob"I think you'll find it's more complicated than that." 21:22, 11 January 2014 (UTC)
Yes, I think perhaps that anyone reading through this discussion will end without even knowing whether we're agreeing or disagreeing at the end (or what it is we're agreeing/disagreeing on)... - GrantC (talk) 21:25, 11 January 2014 (UTC)

## Paste Watson card

OK - I've cut the whole section below. It's longer than the article and simply seems to do more to confuse people than it does to clarify anything.--Bob"I think you'll find it's more complicated than that." 11:09, 12 January 2014 (UTC)

## Wason card problem

The Wason Card problem highlights confirmation bias quite nicely. Four cards are presented to the "player", each labelled with a letter on one side and a number on the other side. There are two cards with letters face up and two with numbers face up (A, B, 1, 2). The following hypothesis is then tested;

"If a card has a vowel on one side, then it has an even number on the other side."

The aim of the experiment is to test this hypothesis by turning over cards to check. You can do this with fewer cards if you recognise how to properly test a hypothesis.

Most people, when given the Wason card problem, will immediately turn over the even number (2) and the vowel (A) to see what is on the other side. This is instinctive because turning these two cards and observing another vowel and an even number respectively would confirm the hypothesis - and without context or applied critical thinking, this will be people's normal approach. However, to fully confirm the hypothesis, a third card would be needed to be flipped; 1, to confirm that it doesn't have a vowel on the other side.

### Solution

Looking more critically, it can be seen that the "2" card does not need to be checked at all. If there is an even number with a consonant on the other side, that has no bearing on the hypothesis that "a vowel always corresponds to an even number". This test cannot fail to confirm the hypothesis because even a negative result says nothing about it.

This is also an instance of the need to take care when dealing with implications: the hypothesis is "vowel implies even," not "vowel if and only if (implies and is implied by) even." The hypothesis can be properly tested with only two card flips. Although only around 10% of people get this first time under experimental conditions, almost everyone tested agreed with the logical answer when it was revealed.

If one sets out to disprove the hypothesis the problem can be solved in two turns, rather than three. The card with 1 on one side is the actual deal-breaker in testing the hypothesis properly. The correct cards to turn over would be 1 and A. First, turning over the odd number and viewing a vowel on the other side of that card would invalidate the hypothesis quickly and more efficiently; vowels shouldn't have odd numbers on the back. This is the main counter-intuitive step that demonstrates the need to try and disprove a hypothesis first. Once the odd numbered card is flipped, the next logical card to turn would then be A to confirm whether it had an even number, and as stated earlier the B and 2 cards are actually irrelevant to proving or disproving the hypothesis because all possible results have no effect. Revealing the opposite side of 2 would either confirm the hypothesis, by displaying a vowel, or say nothing, by showing a consonant (which is the same reason that the B card is uninteresting and irrelevant).Skeptic.com - Critical Thinking mini-lesson 3

### Alternative Presentation

The Wason problem presents a fairly abstract version of a simple hypothesis - because this doesn't necessarily engage the best human cognitive processes, the problem is frequently answered badly. Reformulating the exact same situation with something more visceral does show it to be considerably easier.

Consider the following situation:

You are working in an all-ages club and your job is to make sure that no one under the age of 21 is drinking alcohol. You see four people. You know person A is 40 and person B is 19, but you don't know what either one is drinking. You know that person C is drinking a soft drink, and person D is drinking vodka, but you don't know the ages of either. Of these four patrons, which ones do you need to investigate further?

This question is equivalent to the card problem; with ages substituting for numbers and drinks subtitling for letters. The more concrete and specific application to social mores makes it easier for our socially-inclined brains to see the correct answer: you need worry about only person B and person D! This shows that the difficulty of a problem can greatly depend on what cognitive processes are engaged.

## Intelligent design

This section is blatant coatracking and appears to have entirely replaced the previous contents. Does anybody actually bother to monitor this article?

The use of Intelligent Design as an example (whether you agree with the concept or not) is in itself a clear example of Confirmation Bias. I object on the basis of recursion alone.

## Just added a page quote

Because we all need a little Francis Bacon in our lives. Feel free to remove the quote if it's not suitable. --75.28.97.207 (talk) 22:46, 31 May 2015 (UTC)