PrimalMatch's compatibility engine is built on the HEXACO model of personality structure — a six-factor framework developed through large-scale cross-cultural lexical studies (Ashton & Lee, 2007). HEXACO extends the traditional Five-Factor Model by introducing a distinct Honesty-Humility dimension, which has been shown to predict prosocial behavior, relationship trust, and long-term partnership stability independent of the other factors.
The six dimensions — Honesty-Humility (H), Emotionality (E), Extraversion (X), Agreeableness (A), Conscientiousness (C), and Openness to Experience (O) — capture personality variance that is directly relevant to relationship formation and maintenance. Our matching algorithm weights these dimensions based on the empirical literature summarized below, with particular emphasis on:
H
Honesty-Humility
Predicts sincerity, fairness, and resistance to exploitation in intimate relationships. High H individuals show lower rates of infidelity and greater reciprocity in partnerships.
E
Emotionality
Encompasses emotional reactivity, anxiety, and sentimentality. Research consistently shows that combined high Emotionality in both partners is a significant risk factor for marital dissatisfaction and conflict escalation (Cheon et al., 2024).
X
Extraversion
Measures social self-esteem, boldness, and liveliness. Complementary rather than identical Extraversion levels are often associated with stable dyadic functioning.
A
Agreeableness
Captures patience, forgiveness, and flexibility. High Agreeableness facilitates constructive conflict resolution — a key predictor of sustained relationship satisfaction (Malouff et al., 2010).
C
Conscientiousness
Reflects discipline, organization, and deliberation. Longitudinal data shows that individual-level Conscientiousness is one of the strongest personality predictors of relationship longevity (Bach et al., 2025).
O
Openness to Experience
Encompasses intellectual curiosity, aesthetic sensitivity, and unconventionality. Shared Openness is associated with deeper intellectual alignment and lifestyle compatibility in couples.
Building on DeYoung, Quilty & Peterson's (2007) work demonstrating that each Big Five domain comprises two distinct aspects, our compatibility scoring operates at the aspect level — providing finer-grained personality alignment data than domain-level matching alone. When a user taps into a potential match's profile, they see a trait-by-trait comparison highlighting where they align and where they differ — with plain-language explanations of what each similarity or difference means for long-term relationship outcomes.
Critically, when this data reveals trait combinations that the literature associates with elevated conflict risk, relationship dissatisfaction, or divorce probability, we surface that information explicitly. PrimalMatch is built to be honest about compatibility — including when the honest answer is that a pairing carries significant long-term risk.
The peer-reviewed studies below represent the empirical foundation for both our matching and our compatibility warnings.
