Human Computation

A computing paradigm in which humans perform tasks that computers cannot yet do reliably, often embedded within systems that combine human and machine capabilities. The classic example is reCAPTCHA, which used human text recognition to digitise books while verifying users were not bots. In accessibility, human computation has been applied to tasks such as describing images for screen reader users (VizWiz), correcting speech recognition captions, and transcribing scanned documents in languages where OCR is unreliable. Human computation can be delivered through paid microtask platforms, volunteer efforts, or gamification that makes the work intrinsically engaging.