Watch
Doherty threshold 0:36
A 36-second explainer of Doherty threshold, narrated over the same demo you can try yourself.
Try the interactive Doherty threshold demo
What this video covers
A historical HCI guideline that subsecond system response helps sustain productive, engaged interaction. Treat roughly 400 ms as a design heuristic worth aiming under, not a universal perceptual threshold.
You waved the quick responses straight through, then started calling them laggy long before a full second had passed. That line, near 400 milliseconds, is the Doherty threshold: under it an interface feels like an extension of your thought; over it, you notice the wait and begin to doubt.