How your personality type affects your development


During one of my more recent interviews I got an assesment from two different persons. While I still have no idea about the definitive outcome, the different types of questions they both asked triggered me to think about what kind of personality type they would be, so I started wondering how personality types are related to development....

First things first: MBTI

Before we can determine the effect of your personality on your development, we will start by defining MBTI, so let us begin with the wikipedia definition:

The Myers-Briggs Type Indicator (MBTI) assessment is a psychometric questionnaire designed to measure psychological preferences in how people perceive the world and make decisions.

They do this by categorizing your personality in four dimensions; your gradation in every dimension is not a boolean, but rather a range (i.e. -1 to +1).

I will describe each of the four dimensions in detail, and explain how they impact your development:

#1 Attitude: "Extraversion" versus "Intraversion" (E vs I)

Attitude is about the way evolve an idea and get inspired: some get inspired by doing and experimenting, while others get inspired by thinking about things.

  • Development by people with high "Extraversion" is driven by
    • experimenting with code
    • evolving ideas in small incremental steps by talking with other people
    • doing things right
  • Development by people with high "Intraversion" is driven by
    • an internal thought process
    • thinking ideas through before talking about it with other people
    • doing the right thing

On a sidenote, "extraversion" is not a typo; it is the way you spell this word in MBTI terms.

#2 Percieving: "Sensing" versus "iNtuition" (S vs N)

The second dimension is about how we percieve things... Some need to see the details (sensing), other just have a general sense (i.e. intuition) of what it is supposed to do. This has obviously a rather big impact in the way that we write code...

  • Development by people with high sensing is usually explicit
    • "Hmmz I need to know all the ins and outs before I use this, how does this tiny bit work?"
    • "Always use explicit typing everywhere, no exceptions!!"
    • "This looks dirty, I need to change this"
    • "Coding without conventions? Always use the 'private' keyword, even though it is implicit"
  • Development by people with high iNtuition is usually implicit
    • "I don't care how it works, when it is important to know I will find it out"
    • "dynamic and var are my friends"
    • "I will refactor it when it hurts"
    • "Ok, I will follow the coding conventions if you really force me"

#3 Judging: "Thinking" versus "Feeling" (T vs F)

I quite honestly have not met a single developer who was a "feeling" type; every single one I met was a rational type (which is kind of a logical thing - pun intended).

A lot of recruiters on the other hand, are usually a "feeling" type, hence this is probably a part of the problem I stated in one of my previous blog posts.

#4 Lifestyle: "judging" versus "perceiving" (J vs P)

The final one is about which one of #2 and #3 you use the most to interact with the world: your "judging" or your "percieving part".

  • Development by a "judging" developer
    • usually driven by a detailed plan
    • not deadline-driven
    • tends to be quite rigid when executing something, sometimes to rigid
    • works first, plays later
  • Development by a "perceiving" developer
    • driven by external impulses (Sensing or iNtuition)
    • deadline-driven
    • likes to keep his/her options open, sometimes indecisive
    • works in bursts

So how is this related to the assesment ?

When having an interview, it usually helps if the interviewer's personality matches the interviewee's as much as possible... There are compatibility matrices available for MBTI types which also mention opposites (f.e. my wife is my MBTI opposite), but I think this is not an advantage when doing an interview.

As an ENTP myself, I met two interviewers, and based on their questions I would guess that the first interviewer was an ISTP and the second one an INTP. (Not sure about the first letter, as interviewers tend to be intraverted during an interview.)

It does not take a genious to find out in which interview I performed best...

Update: I got pinged by both an INFP and an INFJ, so apparently the F part is still there for some developers. Next to this I misjudged my interviewers; they are ISTJ and ESTJ.. My bad!!! (but in my defense, the second one still matches my profile better then the first one....)

I also received some food for thought from Rob Ashton:



If you are a developer, this should give you a general idea of the MBTI type you are exactly. If you really want to find out, there is a short free questionaire online to determine your MBTI type here.

On a sidenote, it would be great if the interviewers would be willing to send me a message whether I am correct or not with my guesstimate...

Signing off,