The Formula of Love provides a valuable and detailed account of how individuals fall in and out of love, emphasizing the partner’s meritorious qualities, the appreciation they provide, and our intrinsic need to feel that we matter. According to the theory, love diminishes when either the partner’s merit or their appreciation declines (as articulated in Hypothesis 8 of the target article). While this offers a useful starting point, the proposition reflects a predominantly static and simplified view of love, overlooking its inherently dynamic and multifaceted nature. It seems to suggest that each of the components – partner qualities, appreciation, and our significance quest – remains equally important across interactions and the course of a relationship. Moreover, the model only explicitly acknowledges interpersonal processes in the appreciation component, although such dynamics arguably influence all components.

We propose extending the target article by explicitly integrating the dynamic qualities of romantic relationships, which currently receive limited attention. By “dynamic,” we refer to two core elements: (1) temporal processes, and (2) interpersonal processes.

Regarding temporal processes, romantic relationships evolve over time, from the first encounter to the point at which they end (Eastwick et al., Reference Eastwick, Finkel and Simpson2019). The target article, however, primarily emphasizes components relevant to initial attraction and early-stage relationship development. As relationships progress, different components and relational dynamics become increasingly important – yet these later-stage developments receive little attention in the current framework.

Incorporating findings from relationship science on temporal development would refine and enrich the framework. For instance, in early stages, passionate love – marked by longing, excitement, and uncertainty – plays a central role (Carswell & Impett, Reference Carswell and Impett2021; Hatfield & Walster, Reference Hatfield and Walster1985; Sprecher & Regan, Reference Sprecher and Regan1998). Features such as physical attraction and relational ambiguity enhance perceived partner merit and increase attraction, but these same features tend to lose relevance – or even negatively predict – relationship satisfaction in more established partnerships (Imai et al., Reference Imai, Taniguchi and Umemura2023; McNulty et al., Reference McNulty, Neff and Karney2008; Whitchurch et al., Reference Whitchurch, Wilson and Gilbert2011; Birnbaum et al., Reference Birnbaum, Kanat-Maymon, Mizrahi, Barniv, Nagar, Govinden and Reis2018). Sexual desire, another merit-related factor, is highly salient at the beginning of a relationship, but its role tends to decline over time (Birnbaum & Finkel, Reference Birnbaum and Finkel2015).

As relationships progress, emotional bonds deepen and interdependence grows, and commitment, trust, and investment become key to relationship maintenance and satisfaction (e.g., Arriaga & Agnew, Reference Birnbaum and Finkel2001; Hazan & Shaver, Reference Hazan and Shaver2017; Sternberg, Reference Hazan and Shaver1986). In other words, the relative weight of the Formula’s components shifts: while partner merit may drive early attraction, appreciation – and the interpersonal processes that support it – becomes increasingly central to sustaining love over time. Explicitly incorporating such temporal shifts in the framework would capture love in a more comprehensive, natural way.

Beyond changes over time, love is fundamentally shaped by what happens between partners. Interpersonal dynamics – how individuals interact with and respond to one another – play a crucial role in shaping feelings of love, yet they are underrepresented in the current framework of the target article.

As appreciation grows in significance over time, it likely becomes more malleable and responsive to the relational context. Increased investment and interdependence heighten motivation to preserve the relationship, which can lead to more favorable and biased perceptions of a partner (Lemay & Clark, Reference Lemay and Clark2015). For instance, when partners fall short, individuals often adjust their standards to their partner rather than experiencing a decline in satisfaction (Gerlach et al., Reference Gerlach, Arslan, Schultze, Reinhard and Penke2017). They may prioritize traits their partner already possesses (Fletcher, Simpson, & Thomas, Reference Fletcher, Simpson and Thomas2000) or project their own supportive behaviors onto their partner (Lemay Jr. & Clark, Reference Lemay and Clark2008). These motivated processes illustrate how interpersonal dynamics shape the perceived meaning and salience of both partner merit and appreciation – challenging the model’s assumption that love simply fades when these components decline.

Even in early stages, interpersonal effects override static assessments of partner merit. Empirical evidence shows that relationship-specific effects often outweigh general partner characteristics in predicting initial attraction (Eastwick et al., Reference Eastwick, Finkel and Simpson2019; Joel, Eastwick, & Finkel, Reference Joel, Eastwick and Finkel2017; Luo & Zhang, Reference Luo and Zhang2009). Ideal partner preferences fail to reliably predict partner choice once people begin to interact (Eastwick & Finkel, Reference Eastwick and Finkel2008; Joel et al., Reference Joel, Eastwick and Finkel2017), and the predictive power of perceived partner merit disappears in real-life encounters (Eastwick et al., Reference Birnbaum, Kanat-Maymon, Mizrahi, Barniv, Nagar, Govinden and Reis2011). Instead, partner evaluations become increasingly relationship-specific (Eastwick & Hunt, Reference Eastwick and Hunt2014), further illustrating that love is constructed through ongoing interpersonal dynamics.

In conclusion, incorporating both temporal and interpersonal dynamics into the Formula of Love would yield a more comprehensive and psychologically realistic account of how love develops, persists, and sometimes fades. This integration would not only align the theory more closely with empirical evidence from relationship science but also enhance its ability to account for the dynamic, evolving nature of romantic relationships.