400 Milliseconds. That鈥檚 apparently the magic amount of time to keep a user鈥檚 attention and increase productivity.

Productivity soars when a computer and its users interact at a pace ( < 400ms ) that ensures that neither has to wait on the other.

When building an app or feature in software, if you muddle it down with a zillion steps, bloated javascript and heavy load times then the user is going to be disengaged quickly (I鈥檝e seen it many times when watching a user during an A/B testing session). Think about it, while you were reading this very brief article I wrote, your phone, watch, computer, chat app, calendar and text messenger has probably beeped at you begging for you to tear your eyes away (I mean, it has for me just writing this).

This is one reason video games are so addictive and hook people quickly because the response time to your next action is under 400 ms.

400 milliseconds, not 2,000 (2 seconds) which had been the previous standard Walter J. Doherty, 1982

Making things simple, keeping things neat and fast will insure a better experience for the user. Don鈥檛 make them think

Reference: Laws Of UX