Our Theoretical Framework

1. Common Origins

In 1921, Swiss psychiatrist Carl Gustav Jung published his classic work, Psychologische Typen (Psychological Types). In this book, he proposed a theory about how human consciousness operates. He believed everyone has preferred cognitive functions, and the combination of these functions shapes how we see the world and make decisions.

This theory later inspired several different personality assessment systems:

• 1940s: Katharine Briggs and Isabel Myers (mother and daughter) simplified Jung's theory into a four-letter classification system. This became the Myers-Briggs Type Indicator® (MBTI®).
• 2010s: 16Personalities repackaged the Big Five personality traits into a similar four-letter format, adding a fifth -A/-T dimension, naming it the NERIS Type Explorer®.
• 2025: The 16PTs True Soul Personality Indicator® returns to the roots of Jungian cognitive functions. It also integrates the Big Five personality traits model and mindfulness breathing calibration technology to create a more comprehensive assessment experience.

We share the same theoretical origin as MBTI®—Jung's theory of psychological types. But we've forged our own path.

2. Problems with Existing Tests

Most online personality tests have three fundamental issues:

Problem One: They only give you four letters, lacking depth.
Traditional tests tell you "You are an INFJ" and that's it. But two people with the same INFJ type can operate very differently internally. The four letters are just the surface; the real differences lie in the arrangement of cognitive functions.

Problem Two: Ambiguous theoretical foundations.
Some popular tests use the MBTI's four-letter format, but their underlying theoretical model is completely different. Users think they're taking an MBTI test, but they're actually being assessed by another system. We believe users have the right to know what they're truly being measured against.

Problem Three: They ignore your psychological state during the test.
If you take the same test while anxious, tired, or excited, your results might be completely different. Data suggests that 50-75% of people get a different type when retesting a few weeks later. This isn't because the test itself is inaccurate, but because your psychological state during the assessment influences the outcome.

The True Soul Personality Indicator® offers a comprehensive solution to these three problems.

3. Our Approach: A Three-Layer Integrated Framework

The True Soul Personality Indicator® is the industry's first personality assessment system to integrate three methodologies:

4. Layer One: Jungian Cognitive Functions

Our test questions are designed based on Jung's eight cognitive functions, not simple "either/or" choices. Each question corresponds to a specific cognitive function. We measure the strength of your eight cognitive functions individually, then determine your type based on their unique arrangement.

This means:

• We don't just tell you "what four letters you are."
• We also analyze your core strength (your most natural ability).
• Your auxiliary mode (how you interact with the world).
• Your growth areas (abilities you are developing).
• Your potential blind spots (areas easily overlooked under stress).

Two people with the same INFJ type might have vastly different score distributions across these four levels. This is why cognitive function analysis offers more depth than a four-letter classification.

5. Layer Two: Big Five Personality Spectrum

The Big Five personality traits are the most widely accepted personality model in modern psychology, validated by decades of cross-cultural research. We integrate the Big Five spectrum analysis into your assessment results. This way, you not only know your type but also see your precise position on each dimension.

The dimensions Jung identified in 1921 align closely with the statistically validated Big Five traits:

Jung identified the first four dimensions a hundred years ago. Modern statistics later validated them as four factors within the Big Five. The fifth dimension, Emotional Stability, was not covered by Jung. We've added it in the form of "Soul Stability."

6. Layer Three: Mindfulness Breathing Calibration

This is a unique technology exclusive to the True Soul Personality Indicator®.

Before you begin the assessment, we guide you through a short period of guided breathing. This isn't just for show; it's a carefully designed calibration process.

Why is calibration needed?

Your answers are strongly influenced by your current emotional state. Someone taking a test under work pressure might appear more introverted or anxious than usual. The purpose of breathing calibration is to bring you back to a "baseline state"—your most natural, authentic self.

Scientific Basis:

• Experiments at Harvard Medical School found that just 3-5 minutes of mindful breathing can reduce amygdala activity, lessening the impact of anxiety on your judgment.
• Self-assessments completed in a mindful state align more closely with how others perceive you. Simply put: your self-perception when calm is closer to your "true self."