““0.1 second: This is the limit for perception of cause-and-effect between events. If software waits longer than 0.1 second to show a response to your action, cause-and-effect is broken: the software’s reaction will not seem to be a result of your action. Therefore, on-screen buttons have 0.1 second to show they’ve been clicked; otherwise users will click again. If an object the user is “dragging” lags more than 0.1 second behind the cursor, users will have trouble placing it. This 0.1-second deadline is what HCI researcher Stuart Card calls the perceptual “moment.” It is also close to the limit for perception of smooth animation: 0.063 second/frame (16 frames/second)””
