Ecash fraud resolution

[Riad S. Wahby]

David Honig <dahonig at home.com> wrote:
> Over a decade ago I learned from published work 
> that if a logical problem is posed as cheating (an underage 
> person trying to buy ethanol IIRC) humans are
> much much better at solving the logical problem than if it is
> expressed otherwise.  Some cog scis think this is evidence of 
> hardwiring for social cheating perception.

The example you're thinking of, I believe, comes from Peter Wason.

Imagine you have 4 cards on a table.  On visible side of the cards 
is D, F, 3, and 7.  You are asked to test the hypothesis "If a card has
a D on one side, it has a 3 on the other."  Which cards do you need to
turn over to test this?

Most people would say D, or D and 3.  The correct answer is D and 7.
You need to test that the D has a 3 on the back and that the 7 does not
have a D on the back.  Since the statement is expressed as an
implication (D -> 3), you don't need to check the 3 because it wouldn't
be relevant (3 !-> D).  It's pretty obvious why you wouldn't need to
check the F.

Now, reword this same test that almost everyone fails.  You are a
bouncer at a bar and are enforcing the rule "If a person is drinking
beer, he must be 18 or older."  You may check what people are drinking
or how old they are.  Which do you have to check:  a beer drinker, a
Coke drinker, a twenty-five-year-old, or a sixteen-year-old?  It's now
pretty obvious to everyone that you need to check the first and the
third.

Peter Wason claims that the difference here is not just the concreteness
of one versus the abstraction of the other; his claim is that the
hypothesis "if a person eats hot chili peppers, then he drinks beer" is
no easier to prove false than the original card test.  It is only the
situation in which a person tries to detect cheaters that makes this
test easy. 

For more on this topic, see such books as Steven Pinker's "How the Mind
Works," a reasonable introduction to modern psychology.

--
Riad Wahby
rsw at jfet.org
MIT VI-2/A 2002