Blink and It's Done

Princeton researchers found people form lasting judgments about competence and trustworthiness in roughly one-tenth of a second — faster than a single heartbeat.

Psychologist Nalini Ambady called this thin-slicing: making quick inferences from very brief exposure. Students watching 30-second silent clips of professors predicted end-of-semester ratings with surprising accuracy. The point is not that first impressions are perfect; it is that people begin forming them before much evidence arrives.