You've probably seen the chart. ENFP and INFJ are "soulmates." INTJ and ENFP are "the perfect match." ESTJ and ISFP are "doomed." Sixteen types crossed against sixteen types, color-coded into greens and reds, served up as relationship destiny.
It's also pseudoscience.
If you want to know what actually predicts whether two people will be happy together five, ten, or twenty years from now, you have to leave the type-pair charts behind and look at what longitudinal psychology research has been showing for thirty years. That's the Big Five compatibility story — and it's a lot less catchy than "INFJs and ENFPs were made for each other," but it's the one that holds up under data.
This article walks through what the research actually says about personality and relationship success: which traits matter, why "similar vs. opposite" is the wrong question, and what predicts long-term outcomes more strongly than personality traits ever do.
The type-pair chart trap
Most online "personality compatibility" content is built on the Myers-Briggs Type Indicator (MBTI). The format is simple: pick two types, look up the cell, get a verdict. It feels precise. It feels scientific.
It's neither.
Three problems make MBTI-based compatibility charts almost useless for predicting real relationships:
- MBTI itself isn't reliable. Up to 50% of people get a different four-letter type when they retake the test five weeks later (Pittenger, 1993). If your "type" can flip from one month to the next, type-pair predictions are reading noise.
- Binary categories don't exist in nature. MBTI forces you into "Introvert" or "Extravert," "Thinker" or "Feeler." Real personality is continuous — most people sit near the middle, not the extremes. A chart that buckets two near-middle people into opposite categories will misclassify the relationship before it analyzes it.
- The compatibility predictions aren't peer-reviewed. The "ENFP × INFJ = soulmates" framework comes from interpretive type theory popularized in the 1980s, not from longitudinal couples studies. There's no published dataset behind it.
We've covered the broader reliability case in our Big Five vs MBTI guide. Here we want to focus on the specific question: if not type pairs, then what?
What "compatibility" actually means in research
When psychologists study compatibility, they're not asking "do these two types get along?" They're asking two more useful questions:
- Actor effects: how do your own personality traits predict your relationship satisfaction?
- Partner effects: how do your partner's traits predict your satisfaction (and yours predict theirs)?
A longitudinal study following couples over nine years found that long-term satisfaction is primarily driven by your own traits — Neuroticism, Conscientiousness, and Extraversion — with partner effects and similarity effects being much smaller (Solomon & Jackson, 2014; replicated in more recent work). The folk wisdom that "we're so different, that's why it works" and the equally folksy "we're so alike, that's why it works" are both partial truths. The real story is that certain traits are predictive regardless of pairing, and certain dynamics matter more than trait matching at all.
This is the foundation of personality compatibility for couples as we approach it at Plexality: not a static type-pair lookup, but a profile of two people across continuous trait dimensions plus the systems that govern how they actually treat each other.
The 10-aspect lens: where compatibility actually lives
The Big Five is the scientific gold standard, but it's not granular enough by itself. Two people can both score "high Conscientiousness" and still clash, because Conscientiousness has two distinct facets that pull in different directions.
The DeYoung 10-aspect model (DeYoung, Quilty, & Peterson, 2007) splits each Big Five trait into two sub-aspects:
- Openness: Intellect (abstract reasoning) + Aesthetics (sensitivity to beauty and ideas)
- Conscientiousness: Industriousness (drive, work ethic) + Orderliness (neatness, structure)
- Extraversion: Enthusiasm (warmth, sociability) + Assertiveness (drive, leadership)
- Agreeableness: Compassion (empathy) + Politeness (respect for norms)
- Emotional Stability: Volatility (low = quick to anger) + Withdrawal (low = anxiety, depression)
Compatibility lives at the aspect level. "We're both organized" can mean two industrious workaholics with different orderliness preferences — perfect match on the surface, constant friction in practice. You can dig into each domain in our Big Five personality traits guide.
Conscientiousness: the most consistently predictive trait
Across decades of research, Conscientiousness is the single most reliable Big Five predictor of relationship outcomes — both your own satisfaction and your partner's (Roberts & Mroczek, 2008; Mund & Neyer 2014).
Why? Conscientious partners:
- Follow through on commitments. Industriousness manifests as showing up — for chores, for hard conversations, for the relationship itself.
- Reduce day-to-day friction. Orderliness lowers the frequency of small grievances (laundry on the floor, missed deadlines) that compound over years.
- Are more self-regulated. They're less likely to react impulsively when stressed.
What does this mean for compatibility? Two moderately conscientious people generally do better than one highly conscientious person paired with someone very low. A big gap on either aspect — especially Orderliness — is one of the strongest predictors of recurring conflict in cohabitation research. If one partner needs structure and the other genuinely doesn't, the structured partner ends up doing the household project management, and resentment builds.
Emotional Stability: the dealbreaker dimensions
If Conscientiousness is the strongest positive predictor, low Emotional Stability — particularly the Volatility aspect — is the strongest negative one.
A meta-analysis of Big Five traits and relationship satisfaction found that high Neuroticism in either partner is associated with lower satisfaction, more conflict, and higher dissolution rates (Malouff et al., 2010). The 10-aspect lens sharpens this: it's not "Neuroticism" as a whole that wrecks relationships — it's the two specific aspects, in distinct ways:
- Volatility (anger reactivity) drives conflict escalation. Volatile partners interpret neutral events as threats and respond with intensity. This is the aspect most strongly linked to verbal escalation, contempt, and defensiveness in observational studies.
- Withdrawal (anxiety/depression) drives emotional distance. Withdrawn partners get pulled into rumination, self-criticism, and avoidance. This shows up as the "shutdown" pattern in conflict — partner asks for connection, withdrawn partner pulls away further, anxiety on both sides escalates.
Two volatile partners tend to spiral. A volatile partner with a withdrawn partner often produces the classic pursue-withdraw cycle — and this overlaps heavily with the anxious-avoidant attachment dynamic we'll get to below.
Agreeableness: Compassion + Politeness lower friction
Agreeableness has the second-clearest research signal for compatibility, but only when you split it into its two aspects.
- Compassion (warmth, empathy) is the social glue. Compassionate partners notice when their partner is struggling and respond. Two low-Compassion partners often co-exist parallel rather than connect.
- Politeness (respect for norms, deference) reduces the form of conflict. A polite partner can disagree without contempt; a low-Politeness partner is more likely to escalate to insult, eye-rolling, or sarcasm.
Politeness matters disproportionately here because of John Gottman's decades of observational research. Gottman identified four communication patterns — the "Four Horsemen" — that, when present in conflict, predict divorce with over 90% accuracy in his lab studies: criticism, contempt, defensiveness, and stonewalling (Gottman, 1994). Of those four, contempt is the single strongest predictor of divorce. Contempt is essentially low-Politeness behavior under stress: sneering, mockery, "you're pathetic" framings.
The compatibility insight: two moderately agreeable partners with high Politeness can disagree productively. One low-Politeness partner can sink an otherwise compatible relationship through contempt alone, regardless of what their type-pair chart says. We unpack the specific patterns in our conflict styles in relationships guide.
Where the type-pair charts get it wrong
The popular MBTI compatibility narrative claims certain types "complement" each other (e.g., "Intuitives need Sensors to ground them"). The Big Five evidence says the opposite is closer to true: moderate similarity tends to outperform pronounced opposition, especially on Conscientiousness and Emotional Stability.
But "similar is better" is also too simple. The best summary of the longitudinal evidence:
- Similarity matters more for shared activities and values — Openness similarity, for instance, predicts how easy it is to share interests and intellectual life.
- Differences are tolerable on most traits if both partners score reasonably on Conscientiousness and Emotional Stability.
- Trait similarity does not predict satisfaction by itself once you control for actor effects (Mund & Neyer, 2014). What matters more is who each person is, not how closely they match.
This is why we wrote our Big Five vs MBTI comparison the way we did. Type-pair charts are entertainment. They're not making predictions; they're generating narratives.
The bigger predictors: attachment, EI, and how you fight
Personality traits are part of the compatibility picture, but they're not the whole picture — and they're not even the largest part. Three other dimensions matter at least as much, and often more.
Attachment (anxiety + avoidance)
Modern attachment research operationalizes attachment along two continuous dimensions: anxiety (preoccupation with abandonment, need for closeness) and avoidance (discomfort with intimacy, suppression of needs). These come out of Bowlby and Ainsworth's foundational work and have been refined into self-report measures used in thousands of studies.
Two secure partners (low anxiety, low avoidance) have the easiest time. An anxious partner with an avoidant partner often produces the most distressing pattern — the anxious partner's pursuit triggers the avoidant partner's withdrawal, which heightens the anxious partner's anxiety, and so on. Attachment dynamics often explain conflict that personality traits alone don't. Read more in our attachment styles guide.
Emotional intelligence (the ability model)
Emotional intelligence comes in two flavors. The pop-psychology version (popularized by Daniel Goleman in 1995) is a broad mix of personality traits and self-regulation skills — useful as a frame, but conceptually fuzzy.
The more rigorous version is the Mayer-Salovey-Caruso ability model (Mayer, Salovey, & Caruso, 2008), which treats EI as four measurable cognitive abilities: perceiving emotions, using emotions to facilitate thought, understanding emotions, and managing emotions. This ability model has stronger predictive validity for relationship behavior than trait-EI measures. Partners high in the ability to perceive and understand emotions navigate conflict, support, and repair more skillfully — independent of their Big Five traits.
How you fight (and repair)
Gottman's research shows that the content of conflict matters less than the process. Couples who stay together fight about the same things as couples who split — money, sex, in-laws, division of labor. The difference is how they fight: whether they criticize the behavior or attack the person, whether they take repair attempts seriously, whether contempt enters the room.
This is why we built communication styles in relationships as a separate dimension from traits. Two partners can have ideal Big Five compatibility on paper and still wreck the relationship through communication patterns — and vice versa, less obviously matched partners can thrive if their conflict process is healthy.
How to use this practically
If "type-pair charts are wrong, similarity is partial, and three other dimensions matter as much as personality" sounds complicated — it is. That's the honest answer.
Here's how to use the research without trying to compute compatibility scores in your head:
- Get an accurate Big Five profile for both of you. Free quick tests are fine to start, but the 10-aspect resolution is where compatibility actually lives. Plexality builds this in as part of our relationship compatibility test.
- Pay attention to the high-leverage aspects. Volatility, Withdrawal, Industriousness, Orderliness, and Politeness do most of the predictive work. Big gaps on these are worth conversation; gaps elsewhere usually aren't.
- Layer in attachment. Anxiety and avoidance tend to show up in patterns, not single moments. Notice the dynamic over weeks.
- Audit how you fight, not just what you fight about. Are the Four Horsemen showing up? Is repair happening?
- Don't confuse a profile with a verdict. Compatibility is a starting point for understanding, not a sentence. Most of what makes relationships work is choices made daily — not traits.
Frequently Asked Questions
Are similar or opposite traits better for relationships?
Mostly similar, modestly. Longitudinal research shows that moderate Big Five similarity tends to predict slightly higher satisfaction than pronounced differences, especially on Conscientiousness and Emotional Stability. But the effect is smaller than people expect — your own traits (especially low Volatility and high Conscientiousness) predict your satisfaction more strongly than how closely you match your partner.
Is the Big Five better than MBTI for compatibility?
Yes. The Big Five has decades of peer-reviewed longitudinal couples research behind it; MBTI does not. MBTI's compatibility charts are interpretive narratives without supporting datasets. The Big Five also captures what matters most — Emotional Stability — which MBTI ignores entirely.
Which Big Five trait matters most for relationships?
Conscientiousness is the most consistently positive predictor across studies. Low Emotional Stability — specifically the Volatility aspect — is the most consistently negative one. If you had to pick two dimensions to look at, those are the ones with the strongest evidence base.
Can two people with very different personalities still have a happy relationship?
Yes, frequently. Big differences become problems mainly when they fall on Conscientiousness (especially Orderliness) or Emotional Stability, or when they intersect with insecure attachment or contempt-style conflict. Two partners with different Openness levels or different energy levels can do fine if the foundational dimensions and the communication process are healthy.
Does personality similarity predict marital satisfaction?
Modestly and inconsistently. Some studies find small positive effects of similarity, others find none, and a few even find negative effects in long marriages where similar weaknesses compound (Shiota & Levenson, 2007). The strongest finding across studies: actor effects (your own traits) outweigh similarity effects in predicting satisfaction.
What predicts divorce more than personality traits?
Communication patterns under conflict — specifically John Gottman's "Four Horsemen": criticism, contempt, defensiveness, and stonewalling. Contempt alone predicts divorce more strongly than any personality trait (Gottman, 1994). This is why we treat communication style as a dimension distinct from personality compatibility.
The bottom line
Type-pair compatibility charts are entertainment dressed as science. The actual research story is messier and more useful: a handful of trait dimensions matter (most of all Conscientiousness and Emotional Stability), the 10-aspect view tells you more than the five-trait view, and three other systems — attachment, emotional intelligence, and conflict process — matter at least as much as personality.
Plexality is built around this evidence base. We give you and a partner full Big Five 10-aspect profiles, attachment dimensions, ability-based EI signals, and a structured way to look at how you communicate and resolve conflict together. No "you're an INFJ, you're doomed with an ESTJ" verdicts — just the actual underlying picture.
Ready to see your real compatibility profile? Take the Plexality assessment, then explore personality compatibility for couples and communication styles in relationships to see how the dimensions fit together.
References
- DeYoung, C. G., Quilty, L. C., & Peterson, J. B. (2007). Between facets and domains: 10 aspects of the Big Five. Journal of Personality and Social Psychology, 93(5), 880–896. https://doi.org/10.1037/0022-3514.93.5.880
- Gottman, J. M. (1994). What predicts divorce? The relationship between marital processes and marital outcomes. Lawrence Erlbaum Associates.
- Malouff, J. M., Thorsteinsson, E. B., Schutte, N. S., Bhullar, N., & Rooke, S. E. (2010). The Five-Factor Model of personality and relationship satisfaction of intimate partners: A meta-analysis. Journal of Research in Personality, 44(1), 124–127. https://doi.org/10.1016/j.jrp.2009.09.004
- Mayer, J. D., Salovey, P., & Caruso, D. R. (2008). Emotional intelligence: New ability or eclectic traits? American Psychologist, 63(6), 503–517. https://doi.org/10.1037/0003-066X.63.6.503
- Mund, M., & Neyer, F. J. (2014). Treating personality–relationship transactions with respect: Narrow facets, advanced models, and extended time frames. Journal of Personality and Social Psychology, 107(2), 352–368. https://doi.org/10.1037/a0036719
- Pittenger, D. J. (1993). The utility of the Myers-Briggs Type Indicator. Review of Educational Research, 63(4), 467–488.
- Roberts, B. W., & Mroczek, D. (2008). Personality trait change in adulthood. Current Directions in Psychological Science, 17(1), 31–35. https://doi.org/10.1111/j.1467-8721.2008.00543.x
- Shiota, M. N., & Levenson, R. W. (2007). Birds of a feather don't always fly farthest: Similarity in Big Five personality predicts more negative marital satisfaction trajectories in long-term marriages. Psychology and Aging, 22(4), 666–675. https://doi.org/10.1037/0882-7974.22.4.666
- Solomon, B. C., & Jackson, J. J. (2014). Why do personality traits predict divorce? Multiple pathways through satisfaction. Journal of Personality and Social Psychology, 106(6), 978–996. https://doi.org/10.1037/a0036190