They showed films of the game to Princeton students and Dartmouth students and found sharp differences of perspective. For example, while Princeton students, on average, saw Dartmouth commit 9.8 infractions of the rules, Dartmouth students, on average, saw 4.3 Dartmouth infractions. These findings may not shock you; that tribal affiliation can skew perception is common knowledge. But this study took a real-world example of this bias and carried it from the realm of anecdote into the realm of data. That’s how it became a classic.
