There are certain people in our lives whom we see on a daily basis, or thereabouts -- from our coworkers to the mailman to our partner. But just what effect does seeing these individuals every day have on us? Do they become more endearing to us over time, or do we eventually grow tired of seeing them? While the dynamics of the relationship comes into play (e.g., a toxic vs. caring boss, a fruitful marriage vs. a lousy one), the answer, according to social psychology, is both. In the 1960s, Robert Zajonc coined and demonstrated the mere exposure effect. As the name implies, mere exposure creates a positive bias toward a stimulus. The effect explains why you might find yourself humming a song you loathed the first time you heard it. The propinquity effect is the mere-exposure effect when applied to social contexts. In other words, we become friends with people in terms of functional or spatial proximity. In one study, residents of an apartment building were four times more li...