A single checkout line distributed to multiple clerks experiences fewer delays, yet we perceive that when organized in parallel lines, checkout is faster. In less than 4 minutes, with the aid of low-budget yet engaging animation, Bill Hammack – from the Department of Chemical & Biomolecular Engineering at the University of Illinois – briefly explains why that perception is invalid.

In web design, strive to align user perception with reality and not pander to invalid mental models, instead build trust by providing continual feedback.