Complexity Bias
The tendency to favor complex explanations or solutions over simpler ones, even when simplicity is more accurate or effective.
Origin
Hilary Farris and Russell Revlin at the University of California, Santa Barbara demonstrated the tendency in their 1989 paper "Sensible reasoning in two tasks" in Memory & Cognition. Participants given the number sequence 2, 4, 6 overwhelmingly guessed complex rules like "add two each time" when the actual rule was simply "any three ascending numbers." The bias can be understood as the inverse of Occam's razor, the principle attributed to 14th-century friar William of Ockham that simpler explanations should be preferred. The term gained wider currency through behavioral economics writing in the 2010s.
Everyday Use
When your app is slow, you might assume there's a deep architectural problem when the real culprit is one unoptimized database query. We instinctively feel that complicated problems must require complicated solutions, even when a simple fix would do. Complexity bias is why people trust elaborate financial strategies over straightforward index funds — complexity feels more sophisticated, even when it underperforms.