We’ve developed many tools and assessments to help you explore how your personality traits affect various aspects of your life. Please pick a category below to dig deeper into that specific area.


Our framework


Often the very first question people ask after completing our personality test is “What do these letters mean?” We are of course referring to those mysterious acronyms like INTJ-A, ENFP-T, or ESTJ-A. As you may have already learned from the Type Descriptions or articles on the website, the five letters of these acronyms each refer to a specific trait, with certain trait combinations forming various types and type groups. But before we discuss those traits in depth, let’s explore their historical foundations.

The historical detour

Since the dawn of time, humans have drawn up schematics to describe and categorize our personalities. From the four temperaments of the ancient civilizations to the latest advances in psychology, we have been driven to fit the variables and complexities of human personality into well-defined models. Although we are still some time away from being able to do that, the current models account for our most important personality traits and can predict our behavior with a high degree of accuracy.

Personality is just one of many factors that guide our behavior, however. Our actions are also influenced by our environment, our experiences, and our individual goals. On our website, we describe how people belonging to a specific personality type are likely to behave. We outline indicators and tendencies, however, not definitive guidelines or answers. Significant differences can exist even among people who share a personality type. The information on this website is meant to inspire personal growth and an improved understanding of yourself and your relationships – not to be taken as gospel.

Our approach has its roots in two different philosophies. One dates back to early 20th century and was the brainchild of Carl Gustav Jung, the father of analytical psychology. Jung’s theory of psychological types is perhaps the most influential creation in personality typology, and it has inspired a number of different theories. One of Jung’s key contributions was the development of the concept of Introversion and Extraversion – he theorized that each of us falls into one of these two categories, either focusing on the internal world (Introvert) or the outside world (Extravert). Besides Introversion and Extraversion, Jung coined the concept of so-called cognitive functions, separated into Judging or Perceiving categories. According to Jung, each person prefers one of these cognitive functions and may most naturally rely on it in everyday situations.

In the 1920s, Jung’s theory was noticed by Katharine Cook Briggs, who later co-authored a personality indicator still used today, the Myers-Briggs Type Indicator® (MBTI®). Briggs was a teacher with an avid interest in personality typing, having developed her own type theory before learning of Jung’s writings. Together with her daughter, Isabel Briggs Myers, they developed a convenient way to describe the order of each person’s Jungian preferences – this is how four-letter acronyms were born.

Of course, this is just a very simplified description of the Myers-Briggs theory. Readers interested in learning more should read Gifts Differing: Understanding Personality Type by Isabel Briggs Myers. As we define personality traits and types differently in our model, we will not go deeper into Jungian concepts or related theories in this article.

Due to its simplicity and ease of use, the four-letter naming model has been embraced by a number of diverse theories and approaches over the last few decades, including frameworks such as Socionics, Keirsey Temperament Sorter, Linda Berens’ Interaction Styles, and many others. While the acronyms used by these theories may be identical or very similar, however, their meanings do not always overlap. One of the reasons behind such a lengthy introduction is that we want to make it clear that there is no single definition assigned to these type acronyms – each theory defines them in their own way and it is entirely possible that if you meet five people who all say “I am an INFJ”, their definitions of what INFJ means are going to differ.

Types vs. traits

Regardless of its structure, any type-based theory will struggle to describe or characterize people whose scores lie near the dividing line. A different way to look at personalities is through the lens of a trait-based rather than a type-based model. What do we mean by that? Instead of creating an arbitrary number of categories and attempting to fit people within them, a trait-based model simply studies the degree to which people exhibit certain traits.

You may have heard the term Ambivert, which is a perfect example in this case. Ambiversion means that someone falls in the middle of the Introversion-Extraversion scale, being neither too outgoing nor too withdrawn. Trait-based theories would simply say that an Ambivert is moderately Extraverted or moderately Introverted and leave it at that, without assigning a personality type.

A trait-based approach makes it easier to reliably measure correlations between personality traits and other characteristics – for example, political attitudes. This is why trait-based approaches dominate psychometric research, but that’s more or less the only area where these approaches are dominant. Because they don’t offer types or categorizations, trait-based theories don’t translate as well as type-based theories into specific recommendations and takeaways. Assigned categories such as Extravert or Introvert may be limiting, but they allow us to conceptualize human personality and create theories about why we do what we do – something that a more scientifically reliable but colorless statement, such as you are 37% Extraverted, simply cannot do.

Our approach

With our NERIS® model, we’ve combined the best of both worlds. We use the acronym format introduced by Myers-Briggs for its simplicity and convenience, with an extra letter to accommodate five rather than four scales. However, unlike Myers-Briggs or other theories based on the Jungian model, we have not incorporated Jungian concepts such as cognitive functions, or their prioritization. Jungian concepts are very difficult to measure and validate scientifically, so we’ve instead chosen to rework and rebalance the dimensions of personality called the Big Five personality traits, a model that dominates modern psychological and social research.

Our personality types are based on five independent spectrums, with all letters in the type code (e.g. INFJ-A) referring to one of the two sides of the corresponding spectrum. You can see where you fall on each scale by completing our free personality assessment, NERIS Type Explorer®. This approach has allowed us to achieve high test accuracy while also retaining the ability to define and describe distinct personality types.

Reliability and validity

The social sciences, personality research included, have a problem: when looking at individual human beings, it’s hard to find anything consistent. Reliability and validity – consistent results and measuring what we think we’re measuring – are the two biggest challenges any organization in this field has to contend with. Let’s talk about that.

There are two ways to handle hard questions about reliability and validity. An organization can protect itself from scrutiny by making itself appear reliable, usually by making you pay to even take their assessment, with the claim that cost = quality. This doesn’t stop them from having a quality product, and it doesn’t mean that what they offer won’t impact your life for the better. But you can’t know until you pay – and it’s also easier to convince someone that what they’ve bought is good enough once they’ve already parted with their money.

The other method is for an organization to open itself to the community, making its tools and information accessible and accepting feedback from many sources. Such an organization works to refine itself out in the open. It gives you the grand tour, then lets you decide for yourself whether this is a space in which you can grow.

Yes, anyone can take our assessment, NERIS Type Explorer®, for free. You don’t have to register, sign up for a “free” trial, hire a consultant, or anything like that. But it’s this openness that gives our work strength – because this isn’t just about you. We firmly believe that the more people are aware of strengths and weaknesses related to their personality traits, the better and more understanding this world will be for everyone.

This is why our assessment is available in 30 languages – again, completely for free. Thanks to this accessibility, our assessment has already been taken nearly 100 million times, a humbling yet motivating milestone in our effort to reach the world. We offer plenty of exciting resources for those who wish to go deeper, but we don’t make you pay just so you can glimpse behind the curtain.

Not charging for our assessment is precisely why we were able to make it highly reliable and accurate, across many cultures and languages – as you’ll see from the article linked below, NERIS Type Explorer® has excellent statistical characteristics that set us apart. The assessment’s value is also reinforced by numerous complementary surveys we’ve conducted, analyzed, and published. The thousands of comments people have left on our website are the best testament to the accuracy of our methods.

Not all of our insights will make you smile, but our goal is to give you the truth – because that’s what our research shows, and that’s what you deserve to hear. We’re proud to be able to share such insights, as opposed to flooding your screen with cheesy stock photos and empty buzzwords that you’ll so often see elsewhere. We don’t offer anything we don’t truly believe in – personality testing in job interviews, for instance – and we work very hard to make sure everything that does make it to you is thoroughly verified and validated.

Openness and accessibility issues aside, paid assessments also tend to have much smaller respondent samples, and consequently, are more likely to struggle when it comes to improving or expanding their theoretical framework or ensuring cultural validity. Our philosophy opens us up to more criticism, but that’s exactly why we’re able to grow and improve. There have been many cases, especially with translated versions of our assessment, where we went through multiple iterations in a matter of hours, achieving major accuracy improvements on the same day – a feat that any paid assessment would struggle to compare to.

So, it’s a myth that a personality assessment cannot be free, reliable, and valid. If you’re interested in going into the nitty gritty of statistics and how we’ve verified reliability and validity of NERIS Type Explorer®, please continue to this article.

Let us now go through our five personality aspects one by one, and then move on to the type groups.

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