

Results of yesterday's personality poll: we're strange. - a-priori

On the hypothesis that this site selects for certain personality types that are different from the general population, I decided to run some simple statistics on the results of yesterday's MBTI poll (http://news.ycombinator.com/item?id=943722).<p>I compared the frequencies of each of the types to the population means on the Wikipedia article (http://en.wikipedia.org/wiki/Myers-Briggs_Type_Indicator#Type_dynamics_and_development). The results show that we are a very atypical group indeed:<p><pre><code>  Using a binomial test at a 99% confidence level.
  ISTJ is significant:      1.82% ( 12/660) vs. 11.60% expected.
  ISFJ is significant:      0.61% (  4/660) vs. 13.80% expected.
  INFJ is NOT significant:  2.12% ( 14/660) vs.  1.50% expected.
  INTJ is significant:     31.21% (206/660) vs.  2.10% expected.
  ISTP is significant:      2.42% ( 16/660) vs.  5.40% expected.
  ISFP is significant:      0.15% (  1/660) vs.  8.80% expected.
  INFP is significant:      8.48% ( 56/660) vs.  4.30% expected.
  INTP is significant:     28.94% (191/660) vs.  4.30% expected.
  ESTP is significant:      0.45% (  3/660) vs.  4.30% expected.
  ESFP is significant:      0.15% (  1/660) vs.  8.50% expected.
  ENFP is significant:      3.33% ( 22/660) vs.  8.10% expected.
  ENTP is significant:      8.48% ( 56/660) vs.  3.30% expected.
  ESTJ is significant:      1.36% (  9/660) vs.  8.70% expected.
  ESFJ is significant:      0.76% (  5/660) vs. 12.30% expected.
  ENFJ is NOT significant:  2.27% ( 15/660) vs.  2.40% expected.
  ENTJ is significant:      7.42% ( 49/660) vs.  1.80% expected.
</code></pre>
The data are up-to-date as of about 20 minutes ago. Here's the script I used to generate these results: http://gist.github.com/236850<p>EDIT:<p>Here are the results broken down by pairs:<p><pre><code>  FP is significant:     12.12% ( 80/660) vs. 29.70% expected.
  TP is significant:     40.30% (266/660) vs. 17.30% expected.
  FJ is significant:      5.76% ( 38/660) vs. 30.00% expected.
  NJ is significant:     43.03% (284/660) vs.  7.80% expected.
  NF is NOT significant: 16.21% (107/660) vs. 16.30% expected.
  TJ is significant:     41.82% (276/660) vs. 24.20% expected.
  NP is significant:     49.24% (325/660) vs. 20.00% expected.
  NT is significant:     76.06% (502/660) vs. 11.50% expected.
  EN is significant:     21.52% (142/660) vs. 15.60% expected.
  EJ is significant:     11.82% ( 78/660) vs. 25.20% expected.
  IP is significant:     40.00% (264/660) vs. 22.80% expected.
  IS is significant:      5.00% ( 33/660) vs. 39.60% expected.
  EF is significant:      6.52% ( 43/660) vs. 31.30% expected.
  IT is significant:     64.39% (425/660) vs. 23.40% expected.
  IJ is significant:     35.76% (236/660) vs. 29.00% expected.
  IN is significant:     70.76% (467/660) vs. 12.20% expected.
  ET is NOT significant: 17.73% (117/660) vs. 18.10% expected.
  EP is significant:     12.42% ( 82/660) vs. 24.20% expected.
  ES is significant:      2.73% ( 18/660) vs. 33.80% expected.
  IF is significant:     11.36% ( 75/660) vs. 28.40% expected.
  SP is significant:      3.18% ( 21/660) vs. 27.00% expected.
  ST is significant:      6.06% ( 40/660) vs. 30.00% expected.
  SJ is significant:      4.55% ( 30/660) vs. 46.40% expected.
  SF is significant:      1.67% ( 11/660) vs. 43.40% expected.
</code></pre>
Apparently, 76% of Hacker News is an NT type of one type or another. I've updated the Gist link above with the code that computes this.
======
aikiai
There seems to be a bit of misunderstanding about the purpose and intention of
this test, and the Myers-Briggs type system. I'm by no means an expert, but I
know enough about the system to see there are some knee jerk misunderstandings
going on here. So feel free to correct me if I get anything not exactly right,
but this should raise the level of discourse on this subject a bit I hope.

To talk intelligently about the results of the test, you must first understand
the vocabulary they are using. That vocabulary is more technical than the
common understanding of the words that are used to name the categories. This
test, love it or hate it, was created by people in the sciences, and the
categories, whether useful as predictors or not, have specific definitions.

The M-B test is centered around four behaviors [(N|S)(F|T)] and two attitudes
[I|E]. The attitudes are perhaps the most commonly misunderstood, because we
have strong natural usage around the words extrovert and introvert that is
quite different from the technical definition in the M-B system. For starters,
it is probably safe to just think of these as modifiers on the behaviors, such
that an extroverted behavior is directed out to the world, and an introverted
behavior is directed towards your mental life.

Of the four behaviors [(S|N)(T|F)], two behaviors function to Judge the world
(Thinking, Feeling) and two behaviors function to Perceive the world (Sensing,
iNtuiting). Feeling is another misunderstood one. While it includes
"emotional" decisions, it also includes "going with your gut".

The least obvious piece of the system is how the four letters interact. Lets
take INTP, since for once, we are the majority here, and it is mine, so I can
use myself as the subject to discuss rather than the obnoxious "If one is a
... than he/she..."

What these four letters do (yes, in theory) is establish my PREFERENCE for
these behaviors. From INTP, my core type is NT or Rational (according to
Keirsey). I prefer to perceive through iNtuition, and decide through Thinking.

The I and the P are modifiers on those types. The P tells me that, when
interacting with the world (in my Extraverted attitude), I prefer to be in a
Perceiving behavior. The [I] tells me that, all other things being equal, I
prefer to be in an Introverted attitude.

The primary piece of M-B theory that I find interesting and worthy of debate
is this: A person has a primary Perceiving and Judging behavior, and they tend
to prefer to use one in an Extraverted attitude and the other in an
Introverted attitude.

This implies that, since I prefer to use my Perceiving behavior (iNtuiting) in
my Extraverted attitude, I prefer to use my Judging behavior (Thinking) in my
Intraverted attitude. This is the difference between an INTP and an INTJ.

So, M-B would say my two main behaviors are Ne and Ti. Ok, now let's deal with
the [I]. This tells us which, of the two attitudes I prefer. So, according to
M-B:

My primary behavior is Ti

My secondary behavior is Ne

My terciary behavior is S(i) (sometimes i is not shown)

My inferior behavior is Fe

One actionable result for me from taking this test has been that it reminds me
that I have a tendency to under use my extraverted feeling decision maker.
Which I have found to be true, and so I make sure to consciously bolster this
response when the opportunity to use it presents itself.

In closing, it is crucial to remember that this test determines PREFERENCES.
It says NOTHING about ability or correctness. If you have Judged Thinking
better than Feeling, or think you can perceive more by Sensing than iNtuiting,
than you are probably out of touch with your other behavior. I believe that we
should all strive to be very balanced on this test.

However, I do agree with M-B theory that people do have a tendency to
gravitate to the poles, often because of strength or social culture. I believe
one of the best uses of this test is to recognize which behaviors you prefer,
and also recognize the ones that you could benefit from giving more attention.

Thanks. :)

 _edits for clarity and such_

------
tc
Most significantly, 502 out of the 660 respondents (76.1%) are type NT (11.5%
expected). With a single significant exception (INFP), every non-NT group is
underrepresented. Conversely, _every_ NT group is overrepresented, even the
extroverted types.

Perhaps our Erlang-flooding people-filter has some influence on this.

~~~
a-priori
Thanks, I just updated the original post to include a break-down by pairs.

------
johnmyleswhite
This is a fun analysis to see. Here's a suggestion for cleaning up the stats,
though it won't help you get around people noting that there's a selection
bias for the poll results themselves.

If you're interested in showing that the frequency distribution for
personality types is different on Hacker News than in the general population,
then the right way to show this would be to run a single multinomial test to
see whether your empirical multinomial distribution is outside of the range of
chance variation from the canonical distribution listed on Wikipedia for the
MBTI. See <http://en.wikipedia.org/wiki/Multinomial_test> for a description of
this hypothesis test.

To give you a sense of why your multiple comparisons across binomial tests is
problematic, imagine that the INTP group is underrepresented because all of
the people who would test as INTP tested as ENTP this time around; in this
case, you run two different binomial tests, but you really only have one
result, because the size divergence in one group is effectively the cause of
the size divergence in the other group.

I hope that makes it clear why you should really treat your data set as
containing an N of 1 and doing a simple null hypothesis test of the
probability of getting your results given the canonical values for the global
multinomial distribution, rather than testing based on a series of binomial
marginal distributions.

------
j_baker
So _this_ is why my "free electron" post was so popular here but nowhere else:
<http://jasonmbaker.com/the-free-electron-programmer>

------
jacabado
Would anybody be interested in sharing the results of the Gallup's "Now
Discover Your Strengths" results? Maybe a few of us also have results on that.

------
edw519
The work you've done is interesting and I appreciate it, but it's really
nothing more than a "precise estimate of a wild ass guess".

I have tested as INTJ many times before, but yesterday my result was ESFJ. Go
figure. I've been a programmer all my life and I have the classic personality.
All I did was answer their questions. I remember thinking that many of my
answers could have easily gone either way. Maybe if I took it today (which
isn't a Monday), some answers would be different. I have no idea why the
result would vary so much.

You are doing analysis to 4 significant digits of work based upon the
appropriateness of questions with no significant digits. You've built a
concrete structure on top of quicksand. Nice job, but I really don't think it
means much.

~~~
a-priori
Thanks, I appreciate your feedback. Yes, I definitely should not have given
anything to four significant figures. I did that without thinking; none of the
calculations are precise enough to warrant more than three at most.

I've kept my opinions out of this discussion so far, but I definitely agree
with what you say about the test. While the MBTI undoubtedly indicates
_something_ , its utility and validity are questionable. It's interesting for
novelty value, but that's about it.

I'm definitely in the same boat as you: at various times over the past 5 years
or so I have scored as INTP, ENTP and ISTP, so in both our cases, test-retest
reliability is an issue. (I didn't take the test yesterday, because at this
point I feel I'm too familiar with it to answer without bias.)

I make no claims about how valid this analysis is; it's certainly not going to
appear in a statistics journal any time soon. I just decided to do it for fun
and was surprised by just how drastically different the results are from the
general population.

~~~
j_baker
I think Myers and Briggs would argue that the test is a reflection of how you
see yourself. If you get different results, it's because how you see your
personality has changed. I've tested differently in the past, but as I've
gotten older, I pretty consistently come up with INTP. I think that's because
I know my personality better by now.

At the end of the day, all that matters is how you view your own personality.
The test is just a way to try to pry that data out of your brain.

~~~
a-priori
If that's the case, then it defeats the entire purpose of the test. It's not a
personality test anymore, it's a self-image test. The idea of a personality
test is to dig below your self-image to get a picture of what your 'innate
personality' is. Whether they're successful at doing this is another story,
but that's the idea.

~~~
potatolicious
I don't think there's such a thing as an "innate personality" - I'm a very
different person than I was 10 years ago, and having just taken the test right
now, the results are also likewise different (INTJ -> ESTJ if anyone's
interested).

IMHO your personality is not something set in stone - it's a rather slow-
changing beast surely, but I think it's a fallacy to believe that it's somehow
cemented by some age.

------
dgordon
The ridiculous overrepresentation of INTJ and INTP has shown up everywhere
I've been on the internet -- not quite to this degree, though. That may have
something to do with the places I go, though, since I consistently test as one
or the other.

~~~
DarkShikari
Yup, I've found that as well. For example, here's a poll of 4chan's /jp/:

<http://i36.tinypic.com/3011z11.png>

It matches up surprisingly well with HN, except that (perhaps as expected) the
results are 97% I.

~~~
danteembermage
Wow, so why are people interested in Japan _extremely_ shy? It doesn't seem
like cosplay is inherently an introverted activity.

------
hitonagashi
Surely, given the fact that one group is vastly over represented(in this case
INTJ), it is hardly a surprise that the others have distributions that are
skewed as a result?

~~~
a-priori
Certainly true, and I'd definitely include INTP in that as well. I'm not sure
how to adjust this analysis to reduce that influence. To be honest, statistics
is not my forté.

Any suggestions?

------
seldo
Of course, this really only shows the personality types of people on HN _who
answer polls_. Still, that INTJ/INTP domination is kind of amazing.

~~~
a-priori
Oh, yes. Caveat emptor and all that. This is self-selected, took significant
effort to do (so possibly eliminated busy people), and the test itself is
based on questionable science. This analysis assumes that none of that had any
significant bias.

~~~
nopassrecover
Well if anything you'd expect a bias towards sensing/feeling for these kind of
tests wouldn't you?

------
niyazpk
I should admit that for most of the questions, I could not come up with the
correct answer (yes/no). I feel I answered many incorrectly. Did anyone else
have difficulty in answering the questions objectively?

~~~
robryan
I had this problem with quiet a few of the questions, but the end result
(INTJ) seems to fit well to me when reading the description. This could just
be that I haven't read the other descriptions and am bending it to fit to
myself subconsciously though.

~~~
tokenadult
_but the end result (INTJ) seems to fit well to me when reading the
description. This could just be that I haven't read the other descriptions and
am bending it to fit to myself subconsciously though._

Yes. It is very likely that once you have gone through what appears to be a
laborious procedure to generate a description, you will accept whatever
description comes out of that procedure.

<http://en.wikipedia.org/wiki/Forer_effect>

<http://www.skepdic.com/forer.html>

~~~
nandemo
In this case I think there's a simpler explanation: the result fits us well
because there are so many overlapping questions. You might answer one question
in a way that indicates you as an extrovert, but there will be many other
answers that will clearly mark you as an introvert.

------
jonnytran
You might be interested in a similar poll done a couple years back:
<http://news.ycombinator.com/item?id=204240>

------
nopassrecover
Cool compilation. The NT (logicalness) is strong. It also seems introversion
is strong too.

------
niels
I didn't answer the poll because I don't believe in Myers-Briggs Type
Indicators.

~~~
tc
Does seeing the results affect your belief?

If you take as a given that the HN population is not representative of the
population at large, then it is clear that Myers-Briggs measures _something_ ,
as it correctly identified that.

If you'd asked me for a hypothesis before the survey, I would have predicted a
significant overrepresentation of NT-types. That would seem to give the test
some predictive value, unless you attribute the full significance of the
findings to selection bias in who chose to answer (in which case Myers-Briggs
would be an outstanding predictor of who will answer surveys).

~~~
Retric
It's limited to sixteen personality types and most have trouble picking just
one so I think it's fairly useless.

I can be extremely charming, I like being outgoing in large groups, and a
friend of mine said I was probably the most popular person in high school. I
also dislike most people so I spend a lot of time online. I can be extremely
rational and I have little problems programming computers, but I often make
irrational decisions on a whim because I trust my subconscious way to much.

So, I don't know am I an introvert or an extrovert, rational or irrational? I
honestly don't know and I don't think picking one is important because they
don't tell me something I don't already know.

