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The 11 Reasons We Fall in Love

Falling in love is a quick way for us to undergo rapid self-expansion.

Key points

  • Romantic love occurs due to a combination of general attraction and social factors.
  • When another person is attracted to you or likes you, that can increase your own liking, leading to romantic love.
  • A potential union that satisfies general social norms can contribute to people falling in love.
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A question that receives quite a bit of attention in the psychological literature is why people fall in love. One promising answer is that romantic love occurs when the attributes that generate general attraction and the social factors and circumstances that produce passion are particularly strong.

The general attraction attributes are as follows (Aron, et al. 1989):

  1. Similarity: This includes similarity of people’s beliefs and, to a lesser extent, similarity of personality traits and ways of thinking.
  2. Propinquity: This includes familiarity with the other, which can be caused by spending time together, living near each other, thinking about the other, or anticipating interaction with the other.
  3. Desirable characteristics: This general attraction attribute is particularly focused on an outer physical appearance that is found desirable and, to a lesser extent, on desirable personality traits.
  4. Reciprocal liking: When the other person is attracted to you or likes you, that can increase your own liking.

Two further factors that can help explain why people fall in love involve mate selection (Aron, et al. 1989):

  1. Social influences: A potential union that satisfies general social norms, as well as acceptance of the potential union within one’s social network, can contribute to people falling in love. By contrast, a union that does not satisfy general social norms or is not accepted by one’s social network can result in people falling out of love.
  2. Filling needs: If a person can fulfill needs for companionship, love, sex, or mating, there is a greater chance that the other person will fall in love with him or her.

Another five factors seem to be required for the love to be truly passionate as opposed to being a kind of friendship love (Aron, et al. 1989):

  1. Arousal/unusualness: Being in an unusual or arousing environment can spark passion, even if the environment is perceived as dangerous or spooky (Dutton & Aron, 1974).
  2. Specific cues: A particular feature of the other may spark particularly strong attraction (e.g., parts of their body or facial features).
  3. Readiness: The more you want to be in a relationship, the lower your self-esteem and the more likely you are to fall in love.
  4. Isolation: Spending time alone with another person can also contribute to the development of passion.
  5. Mystery: If there is some mystery surrounding the other person and uncertainty about what the other person thinks or feels, wondering when he or she will initiate contact can also contribute to passion.

Aron et al. (1989) examined which of these factors are most prevalent in college students based on their descriptions of their experiences of falling in love. The researchers found that the most frequently mentioned factor preceding experiences of love was finding certain characteristics of the other person desirable, as well as reciprocity of the experienced emotions. There was a moderate frequency of descriptions mentioning the factors that spark passion (e.g., readiness, arousal/unusualness). There was a low to moderate frequency of descriptions of the other person being perceived as similar to the research participant.

The researchers argue that the self-expansion model proposed in Aron & Aron (1986) predicts this weighing of factors. On the self-expansion model, we have the greatest propensity to fall in love when we perceive the other person as a way for us to undergo rapid self-expansion. Entering a committed relationship requires giving up some of our personal autonomy by including the other person in our life. If the other person possesses desirable characteristics, their presence in our life can be perceived as an expansion of the self rather than a loss of freedom (Aron & Aron, 1996).

Work in neuroscience supports these findings in psychology. The neurochemical profile of people who are in love is characterized by low levels of the satiation chemical serotonin (Zeki, 2007). In this respect, the obsessive component of new love makes it similar to obsessive-compulsive disorder.

It is unsurprising, then, that several of the passion-generating factors, including arousal/unusualness, readiness, and mystery, correlate both with the propensity to fall in love and with increased anxiety. Blood levels of adrenaline and other stress chemicals are increased by anxiety triggers.

As argued by Dutton and Aron (1974), feeling increased levels of adrenaline is sometimes mistaken for a feeling of being in love with a person. Dutton and Aron (1974) found that more men fell in love with an attractive female interviewer when she asked them questions in anxiety-provoking situations (a fear-arousing suspension bridge) compared to calm situations (a non-fear arousing bridge). So, even in the absence of most of the other predictors of the onset of romantic love, meeting someone in an anxiety-provoking situation can cause us to fall in love with that person.

Another interesting feature of love is that a felt proximity to a new lover creates higher levels of the reward and motivation chemical dopamine, whereas distance can lead to cravings. Aron et al (2005) used functional magnetic resonance imaging to study people who were intensely in love from between 1 and 17 months. The subjects viewed a photograph of their beloved and then, after a distraction-attention task, they viewed a photograph of a familiar individual. The researchers found heightened brain activation in the right ventral tegmental area and the right postero-dorsal body and medial caudate nucleus—dopamine-rich areas associated with reward and motivation—in response to the photographs of the individual the subject was in love with. So, when you are in love, the imagined or actual presence of the beloved is rewarding and motivating.

The self-expansion model proposed by Aron & Aron (1986) can explain be used to explain this result: When a person conceives of their love interest and him- or herself forming a tight union, the desirable characteristics of the beloved trigger a reward response. This can prompt us to go out of our way to be with our potential partner in order to experience the most intense feeling of reward.

The self-expansion model also predicts that the similarity and propinquity factors should have a paradoxical effect in initial stages of falling in love but should have a more significant influence on the duration of love (Acevedo & Aron, 2009). The main reason is that familiarity and similarity make it less likely that the other person will constitute an expansion of you, once you include him or her in your life.

These predictions are consistent with findings in neuroscience. Low levels of serotonin are likely counteracted by similarity and familiarity, which can prevent people from falling in love (Zeki, 2007). At later stages of a love relationship, however, these same factors may correlate with higher levels of the attachment and bonding chemicals oxytocin and vasopressin, which have been shown to increase during the phase of a love relationship that fosters romantic attachment and pair bonding (Zeki, 2007).


Acevedo, B P.; Aron, A. (2009). Does a long-term relationship kill romantic love? Review of General Psychology, Vol 13(1), 59-65.

Aron, A & Aron, EN. (1986). Love and the Expansion of Self: Understanding Attraction and Satisfaction, New York, NY, US: Hemisphere Publishing Corp/Harper & Row.

Aron, EN & Aron, A. (1996) “Love and Expansion of the Self: The State of the Model”, Personal Relationships 3, 1: 45–58

Aron A, Dutton DG, Aron, EN, Iverson, A. (1989) “Experiences of Falling in Love”, Journal of Social and Personal Relationships August 6, 3: 243-257.

Aron A, Fisher H, Mashek DJ, Strong G, Haifang Li H, Brown LL. (2005) “Reward, Motivation, and Emotion Systems Associated With Early-Stage Intense Romantic Love”, Journal of Neurophysiology 94, 1: 327-337.

Dutton, D.G., & Aron, A.P. (1974). “Some Evidence for Heightened Sexual Attraction Under Conditions of High Anxiety”, Journal of Personality and Social Psychology, 30 (4), 510-517.

Zeki, S. (2007). “The Neurobiology of Love”, FEBS Letters 581, 14: 2575–2579.

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