Things 122: Linda, Sledding Crow, Brand Promises as Modern Myths

Puzzle The Linda Problem
I see this come up every few years, and get annoyed by it every time. Here’s a typical wording:

Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.

Which is more probable?

  1. Linda is a bank teller.
  2. Linda is a bank teller and is active in the feminist movement.

Most people get this wrong. Why?

Usually I follow up on a puzzle in the next edition, but this one is so annoying I’ll address it below, after these other things.

VideoCrow Sledding
The Atlantic has the perfect headline for this video: “Science Can Neither Explain Nor Deny the Awesomeness of this Sledding Crow.”

At the time of writing, their version of the video is down, but this one isn’t:

(Extended version with same amount of sledding but more corvid activity here)

LinkColour perception and language
Ever since reading 1984 I’ve been doubtful but curious about the extent to which language can influence the way we think or even perceive. In a brilliant couplet of articles about colour on Empirical Zeal, I found out about some really nice experiments that demonstrate a real (albeit small) effect, so I highly recommend reading both part 1 and part 2.

ComicMartin Zutis – Being
In a comic shop in Vienna I came upon a small self-published comic, ‘Being’ by Martins Zutis. Packed with surreal imagery and insights that float around the border between madness and brilliance, I particularly liked this observation:

The news reports we don’t question are myths.

Here’s a tiny snippet, or you can read a slightly longer extract here.

Martin Zutis - Being

Answer – The Linda Problem / Conjunction fallacy (see above)
Most people (85%, apparently) will answer that option 2 is more likely, “Linda is a bank teller and is active in the feminist movement.”

At this point the person who set this problem usually laughs like a supervillain and points out that the probability of two things both being true must always be less than or equal to the probability of just one of those things being true. They will say this is a demonstration of the Conjunction Fallacy.

However, these people are wrong. What it actually shows is that if you choose to go against the cooperative priniciple in communication, people will misunderstand you so much that any attempt to isolate the Conjunction Fallacy is lost.

Consider a slightly different scenario:

Boris: I have two sisters. Alice is a bank teller. Eve is a bank teller and a feminist.
James: Oh, that’s interesting. Why do you think Alice doesn’t consider herself a feminist?
Boris: I didn’t say she wasn’t.

When I ask people where the mistake arose in this conversation, the surprisingly consistent judgement is that Boris was “being a dick”.

More formally, as noted in that article on the cooperative principle, we tend to implicitly assume that when someone is telling us something, they will narrow their focus to only that which is relevant. When Boris states that Eve is a feminist, this suggests this information is (for whatever reason) relevant, so the fact is was not noted for Alice strongly suggests she isn’t a feminist.

Some researchers then restate the problem by making it clear that option 1 is “Linda is a bank teller and may or may not be active in the feminist movement”, and still 57% of people think option 2 is more likely. But the assumption of relevance is still a confounding factor: the lead-in to the question is assumed to be relevant (when in fact it’s explicitly designed to be misleading), so I suspect people will be drawn to option 2 more because of this assumption (perhaps assuming they’ve misunderstood some part of the question) than because they misunderstand probability.

The Wikipedia article on the Conjunction Fallacy is much better than when I first reviewed it, covering these concerns and giving a much better demonstration of the fallacy in question.

(As an aside, I will note that I’ve often indulged in similar deviations from the cooperative principle for the sake of setting some kind of puzzle, although hopefully this is usually clear by context – for example, as I asked in Things 4, how far can a dog run into the woods?)


Things 98: Weakest Link Puppets, GPS Doom, Visual Metaphors

I really like The Weakest Link Puppets Special. There’s something about the way these worlds collide that just keeps me smiling as I watch – childish responses to adult questions, adult responses to childish questions, and a wonderful willingness of all concerned to make what’s ultimately one of the simplest illusions going really work. If you want to see the rest of the episode, YouTube will show you the way.

A New Scientist article on how a surprising amount of our technological world is reliant on GPS.

After last week’s question on old-stuff-on-the-internet, I was looking back at my old Geocities site (now living on my own domain after Geocities shut down) and came upon my old Alternative Newsletters. I like to think of these as precursors to the Things email, but they’re really completely different, so I probably shouldn’t.

Anyway, one of them had the following quiz, which I thought I’d adapt for Things:

1) Is the answer to this question yes?
2) Is the answer to this question no?
3) Is the answer to question 4 maybe?
4) Are most of the answers yes in this quiz?
5) Have you stopped worrying about logical yes/no question traps?
6) If you answered maybe to questions 1-5, ask yourself another question in place of this one: If you cyclically rotate ‘maybe’, ‘no’ and ‘yes’ forwards through the alphabet, then answer questions 3 and 5 again, does this change whether or not you have to answer this question?
7) Answer this question last: What is the answer to question 8?
8) Is the answer to this different in comparison with the answer to the last question?

You don’t need answers, you know how many you got right.
0-2 questions correct: congratulations, you could be sane.
3-5 questions correct: bonus question! Did you get more than 3 correct? Answer, mark, and re-score.
6-8 questions correct: you do not need my congratulations, getting this many correct is its own reward (and punishment)
9+ questions correct: See Me.

A periodic table (actually not really periodic) of metaphors:
(click for big)

Last Week’s Question
Last Week I asked “What is the oldest evidence of your own activity on the internet you can still provide a live link to now”.

For me personally, it’s this review on Amazon dated 24th September 2001. I was active in a few other places before that, but they’re all dead now. Let this serve as a reminder to back up any data you hold dear.

Richard beats this by a long distance, with his usenet post dated 4th February 1992. Nearly 20 years ago! That’s a long time in the world of the internet.

By the way, the natural conclusion of this little game would be to try to find a link to the oldest thing on the internet. I’d have no idea where to begin, but let me know if you do.