

Ask HN: What interesting non-intuitive things do you know? - lionhearted

You know what's interesting?<p>Stuff that's not intuitive. Stuff that would seem so wrong on a quick glance that it never gets explored.<p>These are goldmines for exploring. I bet you know some stuff like that. Care to share it with us?
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lhnz
You might have read the comment by knowledgesale stating at one point that
scientists are incentivized into producing positive results. Now take a look
at this quote from John Holt on 'How Children Fail':

“[I told the fourth-graders] I was thinking of a number between 1 and 10,000.
… They still cling stubbornly to the idea that the only good answer is a yes
answer. This, of course, is the result of miseducation in which “right
answers” are the only ones that pay off. They have not learned how to learn
from a mistake, or even that learning from mistakes is possible. If they say,
“Is the number between 5,000 and 10,000?” and I say yes, they cheer; if I say
no, they groan, even though they get exactly the same amount of information in
either case. The more anxious ones will, over and over again, ask questions
that have already been answered, just for the satisfaction of hearing a yes.”

Notice the similarity? The lesson for me was that: action is information.
(Positive or negative it's still useful.) If you keep this in mind it also
helps realise that there are two sources of action, yourself and others --
both should be used to feed your mind.

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knowledgesale
The p-value [1] criterion is often used to test a proposed hypothesis in
medical and social science research papers. When you stumble upon something
along the lines of "studies that shown that eating broccoli makes people
happy" in your everyday life, it comes down to the p-value calculation being
small enough <0.05 for the before and after gathered datasets.

The p-value method is practically a standard for scientific reporting in some
fields. It also has some drastic shortcomings, including, e,g., dramatic
instability for tests with only little data [2].

Naturally, people realize that and try to use additional tools and criteria
when available. However, scientists are pretty brutally incentivized to
publish positive results and, as a result, more often than it should be, too
much weight is put on the single p-value criterion.

With issues like this in mind, in my opinion, it makes sense to be somewhat
skeptical when seeing reports in the news that "A effects B" and definitely
not to rush with the conclusions. Trivial, I know.

The [3] video pretty much sums it up and by all means is worth a watch.

\-------------------

[1] <http://en.wikipedia.org/wiki/P-value>

[2] <http://en.wikipedia.org/wiki/P-value#Problems>

[3]
[http://www.youtube.com/watch?feature=player_embedded&v=e...](http://www.youtube.com/watch?feature=player_embedded&v=ez4DgdurRPg)

~~~
tokenadult
This is an important issue. The article "Warning Signs in Experimental Design
and Interpretation"

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

by Peter Norvig, director of research at Google, has good follow-up on what we
CANNOT assume just because a study has a finding that has met the p-value
criterion.

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caw
I'm not sure if you'd find this interesting or not, but your server
performance can actually depend on your memory configuration.

For example, you should definitely populate the dual channel, tri channel, or
quad channel recommended. However, if you populate the second set of DIMMs on
an Intel platform you'll get slower memory performance. So your 1333 MHz
memory will end up being 1066, or your 1066 will be 800. You'll notice this
resultant speed of course, but you won't realize it's bad until you have a
second server with a slightly different memory configuration.

Additionally, there are situations where a hex core will have reduced
throughput over a similarly clocked quad core, particularly if it's IO
constrained for either memory (see #1) or disk.

If your check this on your servers and swap out the memory, and application
speeds up because of this tidbit, please let me know :) I think this qualifies
as non-intuitive because unless you're a sysadmin you wouldn't think to
optimize this part of your hardware in your stack.

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clyfe
<http://en.wikipedia.org/wiki/Benfords_law>

> Benford's law, also called the first-digit law, states that in lists of
> numbers from many (but not all) real-life sources of data, the leading digit
> is distributed in a specific, non-uniform way. According to this law, the
> first digit is 1 about 30% of the time, and larger digits occur as the
> leading digit with lower and lower frequency, to the point where 9 as a
> first digit occurs less than 5% of the time. This distribution of first
> digits is the same as the widths of gridlines on the logarithmic scale.

> This counter-intuitive result has been found to apply to a wide variety of
> data sets, including electricity bills, street addresses, stock prices,
> population numbers, death rates, lengths of rivers, physical and
> mathematical constants, and processes described by power laws (which are
> very common in nature). It tends to be most accurate when values are
> distributed across multiple orders of magnitude.

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kyle_martin1
I've found that Parkinson's Law is quite useful for being extremely
productive. The law states that "Work expands so as to fill the time available
for its completion." In other words, if you give yourself 30 minutes to
complete a task (despite if it actually will) you will work harder because
you've created a sense of urgency for yourself.

Read more here: <http://en.wikipedia.org/wiki/Parkinsons_law>

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dholowiski
This may sound weird, but after using the bathroom some people wipe while
standing up and some wipe while sitting down. And each group (in general) is
shocked to find out that there is another way to do it.

Not computer related but i find it fascinating that so many people do
something one way, and are totally shocked, mind-blown to find out that it can
be done another way too.

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naf
The music from my father. I never thought I'd end up listening to the same
music as him, which seemed kinda old-fashioned when I was just a teenager.
Unfortunately he passed away six years ago. It makes me smile we can still
share common thoughts and feelings through his music today.

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Mz
Sometimes, the solution to really deadly (or deadly serious) situations is to
reduce the force with which you meet it rather than trying to overcome it with
a higher level of force. In essence: Gentleness is an antidote to violence
better than bigger, more powerful violence. This seems to be the opposite of
what most people believe.

~~~
lhnz
Any specific examples? Without a frame I'm having difficulty in validating
this.

~~~
sathishmanohar
Ever Tried Lock picking? This perfectly applies there ;)

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davidhansen
Bayesian logic and reasoning.

