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The mere exposure effect demonstrates that repeated, non-reinforced exposure to a stimulus increases liking for it. In the context of interpersonal attraction, physical proximity increases exposure frequency, which in turn increases liking independent of the quality of initial interaction. This effect is robust across cultures and suggests that proximity is a powerful determinant of relationship formation.
Examine dormitory assignment studies where random room assignments predict friendship formation, or analyze online dating patterns by geographic distance to see how proximity operates even in virtual spaces.
From your introduction to social psychology, you know that people don't form relationships in a vacuum — social context shapes who we even encounter, let alone come to like. Propinquity (physical proximity) is one of the most robust predictors of relationship formation, and understanding why it works requires grasping the mere exposure effect, one of psychology's most replicated phenomena.
Robert Zajonc demonstrated in 1968 that mere repeated exposure to a neutral stimulus, with no reinforcement of any kind, reliably increases liking for it. Participants shown abstract shapes, photographs of strangers, or even Chinese characters they couldn't read rated more frequently shown stimuli as more pleasant than less frequently shown ones — despite having no positive interactions with any of them. The effect is strongest when people are unaware of how many times they've been exposed to something (subliminal or incidental exposure) and holds across cultures, age groups, and stimulus types. The leading explanation is processing fluency: familiar stimuli are processed more easily and quickly, and that fluency generates a faint positive affect that gets attributed to the stimulus itself.
How does this connect to proximity? Physical proximity determines exposure frequency. You're more likely to encounter your neighbor, your classmate, the person whose desk is next to yours — not because you chose them, but because spatial structure creates contact. The classic Festinger, Schachter, and Back (1950) study of MIT housing found that residents were most likely to be friends with next-door neighbors, and that architectural features creating functional proximity (like where the mailboxes were located) predicted friendships even better than raw physical distance. Functional proximity — the degree to which your path through daily life crosses with someone else's — matters more than simple physical distance.
Two important nuances sharpen the picture. First, the mere exposure effect doesn't rescue a bad first impression — it amplifies whatever initial evaluation exists. If a first encounter is negative, repeated exposure tends to deepen disliking rather than neutralize it. This is why proximity-based relationships in forced-contact settings (prisons, unfriendly workplaces) sometimes produce hostility rather than friendship. Second, the effect operates in digital spaces as well: seeing someone's name or face repeatedly in an online platform, even without direct interaction, increases liking — which has implications for how social media algorithms shape interpersonal attraction by controlling who appears on your feed. The underlying mechanism is exposure frequency, not face-to-face contact per se.