The Self-Expansion Model: How Love Helps Us Grow Beyond Ourselves
Sunday, August 17, 2025.
Love changes us.
Not in the Hallmark sense, but in the literal sense: who we think we are, the skills we use, even the way we move through the world.
Psychologists Arthur and Elaine Aron built an entire program of research around this idea, calling it the Self-Expansion Model.
The claim is simple but startling: romantic relationships thrive when they allow us to expand our sense of self by including our partner’s traits, perspectives, and resources (Aron & Aron, 1986).
In other words, we don’t just fall in love with another person—we also become enthralled with the notion of becomng a vaster version of ourselves.
What Self-Expansion Really Means
The Self Expansion Model rests on a clear motivational drive: people want to enhance their effectiveness in the world. Close relationships are one of the fastest ways to do that. Through intimacy, we gain access to our partner’s knowledge, social networks, and experiences.
This process is often measured with the now-classic Inclusion-of-Other-in-Self (IOS) scale, a simple overlapping Venn diagram that reliably predicts closeness and satisfaction (Aron, Aron, & Smollan, 1992).
This isn’t just conceptual.
In one prospective study, students who happened to fall in love during the semester showed measurable self-concept growth—more roles, more traits, more confidence—over ten weeks (Aron, Paris, & Aron, 1995). Falling in love, it turns out, makes the self feel bigger.
The Key Finding Most Couples Overlook
The Arons discovered something that therapists and couples have long suspected: boredom corrodes, novelty repairs.
When couples engage in novel and mildly challenging activities together, they reliably report higher relationship quality. The effect is surprisingly strong, even in laboratory tasks as silly as a seven-minute obstacle course (Aron, Norman, Aron, McKenna, & Heyman, 2000).
The mechanism isn’t just “fun.” It’s expansion.
Novelty makes you feel more capable and more alive, and because the experience is shared, you link that sense of growth to your partner.
This principle extends beyond couples. Individual self-expansion—learning a skill, joining a new community—boosts personal well-being and often enriches the relationship too (Mattingly & Lewandowski, 2013).
Recent work even shows that higher self-expansion in romance predicts lower depressive symptoms, suggesting that growth through love has mental health benefits (McIntyre, 2023).
How This Plays Out in Real Life
Early love feels enormous for a reason. Self-concept actually expands in measurable ways during those first weeks (Aron et al., 1995).
Long-term love needs scheduled growth. Couples who plan novelty—taking a class, exploring a new place, trying a role reversal at home—reignite expansion and satisfaction (Aron et al., 2000).
Support each other’s solo projects. When one partner pursues growth independently, the relationship often benefits if the other encourages it (Aron & Tomlinson, 2018).
The Nuance: Growth Isn’t Always Good
Too much overlap blurs identity. High IOS scores predict closeness, but excessive merging can erode self-concept clarity.
Breakups often trigger disorientation because the “expanded self” suddenly collapses (Lewandowski, Aron, Bassis, & Kunak, 2006).
Novelty ≠ danger. The strongest effects come from mild challenges—silly games, shared firsts—not reckless thrill-seeking. The point is shared growth, not adrenaline (Aron et al., 2000).
Similarity still matters. Dissimilarity can spark growth, but too much turns daily life into hard labor. The sweet spot is complementary novelty—different enough to expand you, similar enough to sustain you (Mattingly, Tomlinson, & McIntyre, 2020).
Love as an Engine of Becoming
What the self-expansion model ultimately tells us is that love isn’t just about comfort or passion. It’s about becoming.
The classic studies showed that closeness grows when partners help each other explore new roles and possibilities. Newer research adds nuance, showing that expansion buffers against depression, supports resilience after breakups, and underpins the everyday satisfaction of long-term bonds.
If relationships feel stagnant, it’s not necessarily because affection has faded—it may be because expansion has stalled.
The task for couples, then, is not only to hold on to each other, but to keep making each other bigger.
Love works best when it acts as an engine of identity, pulling us forward into versions of ourselves we could never have reached alone.
Be Well, Stay Kind, and Godspeed.
REFERENCES:
Aron, A. (2022). Self-expansion motivation and inclusion of others in self. Personal Relationships, 29(3), 600–627. https://doi.org/10.1177/02654075221110630
Aron, A., & Aron, E. N. (1986). Love and the expansion of self: Understanding attraction and satisfaction. New York, NY: Hemisphere. https://books.google.com/books/about/Love_and_the_Expansion_of_Self.html?id=8KePQgAACAAJ
Aron, A., Aron, E. N., & Smollan, D. (1992). Inclusion of Other in the Self Scale and the structure of interpersonal closeness. Journal of Personality and Social Psychology, 63(4), 596–612. https://doi.org/10.1037/0022-3514.63.4.596
Aron, A., Norman, C. C., Aron, E. N., McKenna, C., & Heyman, R. E. (2000). Couples’ shared participation in novel and arousing activities and experienced relationship quality. Journal of Personality and Social Psychology, 78(2), 273–284. https://doi.org/10.1037/0022-3514.78.2.273
Aron, A., Paris, M., & Aron, E. N. (1995). Falling in love: Prospective studies of self-concept change. Journal of Personality and Social Psychology, 69(6), 1102–1112. https://doi.org/10.1037/0022-3514.69.6.1102
Aron, A., & Tomlinson, J. M. (2018). Love as expansion of the self. In R. J. Sternberg & K. Sternberg (Eds.), The new psychology of love (2nd ed.). Cambridge University Press. https://assets.cambridge.org/97811084/75686/excerpt/9781108475686_excerpt.pdf
Lewandowski, G. W., Jr., Aron, A., Bassis, S., & Kunak, J. (2006). Losing a self-expanding relationship: Implications for the self-concept. Personal Relationships, 13(3), 317–331. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1475-6811.2006.00120.x
Mattingly, B. A., & Lewandowski, G. W., Jr. (2013). The power of one: Benefits of individual self-expansion. The Journal of Positive Psychology, 8(1), 12–22. https://www.tandfonline.com/doi/abs/10.1080/17439760.2012.746999
Mattingly, B. A., Tomlinson, J. M., & McIntyre, K. P. (2020). Advances in self-expansion. In L. V. Machia, C. R. Agnew, & X. B. Arriaga (Eds.), Interdependence, interaction, and close relationships (pp. 245–267). Cambridge University Press. https://doi.org/10.1017/9781108645836.012
McIntyre, K. P. (2023). Romantic relationships and mental health: Investigating the role of self-expansion on depression symptoms. Personal Relationships, 30(3), 522–541. https://doi.org/10.1177/02654075221101127