Kruglanski et al. offer a compact motivational account of romantic love anchored in the fundamental human need for significance. The most glaring omission of their framework is its neglect of biological compatibility as a crucial determinant of romantic attraction. We argue, from the perspective of the Tie-Up Theory (Lucchi Basili & Sacco, Reference Lucchi Basili and Sacco2016, Reference Lucchi Basili and Sacco2020), that no satisfactory model of the mechanisms driving romantic attraction and attachment may overlook their basic biopsychological components. Specifically, women’s screening of potential partners operates through biosexual channels, carrying out sophisticated compatibility assessments via the processing of physical, chemical, and behavioral signals. Such assessments encompass olfactory cues (Saxton et al., Reference Saxton, Lyndon, Little and Roberts2008), vocal characteristics (Feinberg et al., Reference Feinberg, Jones, Little, Burt and Perrett2005), movement patterns (Provost, Troje, & Quinsey, Reference Provost, Troje and Quinsey2008), and somatic traits (Hönekopp et al., Reference Hönekopp, Rudolph, Beier, Liebert and Müller2007), among others. Crucially, these compatibility evaluations operate predominantly at subconscious levels, largely independent of conscious evaluations of partner “merit” or their potential contribution to personal significance.

This biological channel cannot be reduced to Kruglanski et al.’s “merit” factor. A male partner might possess extraordinary wealth, social status, and social validation, yet fail to ignite romantic attraction if fundamental biological compatibility is absent. The authors’ example of Prince Myshkin in Dostoevsky’s “The Idiot” paradoxically illustrates this limitation. Despite his exceptional moral qualities and Aglaia’s initial attraction, their relationship flounders not merely on social impropriety but on a deeper biobehavioral incompatibility, which becomes manifest at the engagement party: his annoying tone of voice, clumsy bodily movements, and culminating epileptic seizure are all adverse biological signals. The Tie-Up Theory would interpret this as a failure of biological compatibility testing (the one that counts for female bonding) that no amount of merit or appreciation can overcome.

Focusing exclusively on psychologically mediated pathways to significance, Kruglanski et al.’s model suggests that romantic attraction can be reduced to a deliberate assessment of significance-enhancement potential. This misunderstands how attraction operates through deep-seated biological mechanisms that are largely impervious to conscious, socially informed, significance-seeking motivations. Women may consciously value a partner’s merit and appreciate their devotion and yet find themselves unaccountably drawn to someone who offers less “significance” but triggers powerful biological compatibility responses. These seemingly irrational choices do not reflect a failure of significance-seeking but the operation of a parallel biological evaluation that the model cannot account for.

The Tie-Up Theory also exposes how Kruglanski et al. oversimplify psychological compatibility itself by treating appreciation as a uniform construct operating similarly across genders. In fact, psychological compatibility is processed through fundamentally different mechanisms in men and women. Men’s partner selection focuses primarily on psycho-emotional dimensions, making psychological compatibility central to their capacity for long-term romantic commitment. Women’s active psycho-emotional competence, conversely, allows them to engage in psychological bonding more flexibly across multiple relationships, reducing their dependence on any single source of affective reward. This gendered dimorphism in psychological processing has profound implications. Men’s emotional receptivity makes them more dependent on romantic relationships for psychological significance, explaining their greater vulnerability to relationship loss (Kiecolt-Glaser & Newton, Reference Kiecolt-Glaser and Newton2001; Hewitt & Turrell, Reference Hewitt and Turrell2011). Women’s emotional activity enables them to derive significance from broader social networks, making partner appreciation less critical to their overall sense of mattering (Rose & Rudolph, Reference Rose and Rudolph2006).

Furthermore, by treating “merit” as a unified construct, Kruglanski et al. obscure how different partner qualities interact with gender-specific compatibility mechanisms. What constitutes worthiness differs between men and women due to their different active/receptive orientations. Moreover, worthiness assessments pertain to active areas, which are sensitive to social signals but are not the loci of the key compatibility tests that pave the way to actual bonding. Men’s sexually focused active orientation prioritizes physical attributes tied to fertility and reproductive potential, not merely as sources of social status but as direct triggers for sexual activation and interest. Women’s emotionally focused active orientation rather emphasizes psychological and social qualities signaling emotional intelligence, empathy, and relational competence. These differences reflect not just cultural conditioning but also fundamental asymmetries in how men and women process relational information, and at any rate, neither of these active orientations controls attraction from the male or the female side in its deepest sense.

The multiplicative model’s prediction that love likelihood drops dramatically when any factor falls below threshold appears mechanistic and fails to account for the complex compensatory dynamics observed in actual relationships. The Tie-Up Theory illustrates how relationships can persist despite absent appreciation or minimal merit if gender-specific biological and psychological compatibility signals ignite a powerful bonding dynamic. Conversely, relationships meeting all of Kruglanski et al.’s criteria may inexplicably fail when compatibility factors are misaligned. The model’s inability to explain why some “perfect on paper” relationships never take off while seemingly mismatched couples thrive points to overlooked key mechanisms beyond significance-seeking.

Most critically, Kruglanski et al.’s model cannot adequately explain relationship dissolution patterns. If love were primarily about significance enhancement, we would expect relatively gender-symmetric dissolution patterns, with partners leaving when significance gains diminish or fade. Instead, the Tie-Up Theory naturally explains why relationship dissolution follows predictable gendered patterns, which are different in short-term and long-term relationships. In a short-term context, when (direct) rewards cease in the sexual domain, non-tied-up men disengage as their active area loses stimulation. When (direct) emotional rewards diminish, non-tied-up women’s active emotional area seeks alternative outlets. However, in a long-term context, for tied-up men and women, respectively, it is the other factor that is critical: lack of (indirect) psycho-emotional rewards disengages the receptive area of tied-up men, and lack of (indirect) sexual/biological rewards turns off the receptive area of tied-up women. The complex dynamics of who leaves whom and when depends not on significance calculations but on where breakdown occurs in the flow of mutually administered direct and indirect rewards, which in the best cases might have been organized into a full-fledged Tie-Up Cycle. The theory distinguishes between cooperative, conflictual, and tragic tie-ups (Lucchi Basili & Sacco, Reference Lucchi Basili and Sacco2020), each with distinct dissolution patterns that Kruglanski et al.’s unitary significance model cannot differentiate. A tragic tie-up, for instance, where both partners are bonded but their active areas oppose each other’s compatibility signals, may persist despite providing minimal significance enhancement or even plain psychological disruption, because the underlying bonding mechanisms remain intact.

By neglecting the asymmetric, dynamic, and fundamentally psychobiological nature of romantic bonding, Kruglanski et al. provide an incomplete account that captures only some facets of the conscious, culturally mediated surface of a much more profound, layered process. A complete theory must integrate these multiple levels, recognizing that the feeling of significance may be as much a consequence as a cause of romantic bonding. The quest for significance may influence partner selection and relationship maintenance, but it works within the constraints imposed by more fundamental biopsychological mechanisms.