Evoked Potential Practice Exam 2026 – The Comprehensive Resource to Achieve Exam Success!

P300 reflects how the brain updates its mental model of what is task-relevant and surprising, driven by where attention is directed and how much cognitive control the task requires. In an active condition you must detect a target and respond, which adds motor preparation and decision-making alongside stimulus evaluation. This generally increases engagement with the target and can amplify the P300, producing a clearer and sometimes larger response. In a passive condition you still attend to the stimuli, but there’s no requirement to act, so the additional motor and decision processes are minimized. The P300 can still appear in passive tasks if attention is sustained, but its amplitude is often smaller compared to active tasks. So the best description is that active requires a response while passive does not, and both can elicit P300 with possible amplitude differences.