Software Developers and Personality Type

I’ve always been fascinated by psychometric tools and the various personality and temperament theories they reflect. You’ve probably encountered at least one of these tools. Maybe you’ve participated in a True Colors workshop or completed a Myers-Briggs Personality Type Inventory. You may have considered it all bunk. Or maybe you were astounded by what the process revealed about you and the people around you.

Whatever you and I believe about the validity or accuracy of the tools, the premise that people have distinct personality traits and characteristics (in spite of immense variation), is incredibly persistent!

A Brief History of Temperament Theory

One of the earliest documented systems for identifying traits of personality and temperament started out as a system of medical diagnosis called Humorism. Emerging from Egypt and Mesopotamia it was systematized by ancient Greek thinkers around 400 B.C.[1] According to this theory, the human body is filled with four basics “humors”: black bile, yellow bile, phlegm, and blood. When the four substances are in balance, the body is healthy. A surplus or shortage of one or more humors, however, affects both the health and personality.

Over time, certain characteristics were identified with each of the four humors. People with too much blood were sanguine, those with too much phlegm were phlegmatic, those with too much yellow bile were choleric, and those with too much black bile were melancholic (although the words they used didn’t carry quite the same meaning as they do today).

The idea that these four substances rule our physical well-being was gradually replaced with a more modern understanding of anatomy and the circulatory system, yet the notion of four temperaments has survived for over 2,000 years and continues to generate new approaches. Here are a few examples and how they are related.

chart comparing different temperament models

Myers-Briggs Type Inventory (MBTI)

Dozens of models for assessing personality type, temperament, working style, preferred thinking mode, and fit, have been developed in the intervening years. One of the most enduring has been the MBTI.

Katharine C. Briggs, and Isabel Briggs Myers expanded on Carl Jung’s research and personality theory to create the MBTI. While most temperament models identify four temperaments, the MBTI uses four scales which combine to create sixteen distinct personality types. According to MBTI, we each have a primary mode of operation along four dichotomies:

  1. Our energy flow (Extroverted or Introverted)
  2. How we take in information (Sensing or iNtuitive)
  3. How we prefer to make decisions (Thinking or Feeling)
  4. The basic day-to-day lifestyle that we prefer (Judging or Perceiving)

The MBTI aims to identify an individual’s preferences along these four scales to promote awareness of self and others and to increase tolerance and appreciation of inherent differences.

Software Developers and Personality Type

What does all this have to do with software developers? To begin with, some of the clearest examples of personality type variation I’ve seen have been at companies that develop software—most often exhibited in the form of communications challenges! So I was excited to come across a study[2] that set out to determine whether software developers reflect a different personality type mix than the overall population.

The results are fascinating and offer some excellent insight for those working or managing in these environments.

In June 2013, Developer Media asked professional developers on, one of the world’s largest developer communities, to take the MBTI and share the results. The study found:

  • 70% of developers fell into five personality types.
  • The balance (30%) were distributed across the remaining 11 personality types.
  • Only 2-3% of developers fell into each of the other 11 types.

One of the most surprising facts revealed by the study was the frequency of the ISTJ personality type, previously thought to be the most common among developers. While ISTJ did come in second, it was not a close second, and the proportion of ISTJs in the study was consistent with the broader population distribution in the US. On the other hand, the most common type in the study, INTJs, were dramatically over-represented among developers.


bar graph showing the distribution of personality types among software developers studied

Source: Developer Media

What Does Developer MBTI Data Tell Us?

Two significant insights jump out at me from these results.

  1. While the overall population is about 6% NT, over half the developers in the study reported as NT. That is a significant skew. The MBTI would describe NTs as intuitive, strategic, logic-driven thinkers. Keirsey describes them as “Rational;” or, as the researchers conclude: “developers are highly competent, driven by technical achievement, and skeptical of everything.”
  2. The second thing that occurred to me is the potential impact of this dynamic on those developers who are not NTs. Although clearly outnumbered, the STs can probably hold their own on the logic front, but will likely struggle with the typical NTs mental leaps. As for the relationship oriented NFs (AKA Keirsey’s “Idealists”) on the team, being surrounded by logic-driven skeptics all day might feel a bit like working inside a food processor.

Also of note is the heavy weighting toward introversion in the top five types that emerged from the study. Not surprising perhaps, but definitely relevant.

Based on the clear majority of personality traits demonstrated by this study, communicating with developers could present some challenges. Here are a few important things to keep in mind:

  • First and foremost, information must be concrete and evidence based. Unsubstantiated opinion will be rejected. Detail is required to back up conclusions, but be sure to provide high level strategic summaries for quick consumption.
  • Given the tendency for hard-wired skepticism, be prepared for pointed debate, regardless of the evidence. Stick to the data. Avoid emotional arguments which will frustrate them and undermine your credibility in their eyes. Be certain, speak with authority and back it up with proof.
  • With the introvert skew, understand that time and space may be needed by many to process new information and think about the implications. Sometimes input will have to be extracted.
  • Watch for signs of distress, high frustration or extreme withdrawal. These might be your outlier NFs who are struggling to fit into an NT dominated peer group. You can help these individuals cope by offering them the space to vent privately and helping them reaffirm the values and purpose behind their contribution to the team.

Having watched and participated in the dynamics of software development teams, the results of this study didn’t surprise me. I’ve also found that NTs are the least likely to accept the validity of personality type theory since the science is “too fuzzy” for them. And yet, they invariably recognize themselves in the descriptions and preferences identified for their type. Most likely, you will too.


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