A response time that does not exceed 400 milliseconds (4/10ths of a second). Conceived by Walter Doherty and Ahrvind Thadani, the Doherty threshold is an objective for keeping the user thoroughly engaged when interacting with a computer.
If a response appears after the 400 ms threshold, users eventually become disinterested according to a study done in the late 1970s. Doherty discovered that the longer the response time, the more time users take to think about the next task and productivity is reduced. The study was published in the IBM Systems Journal in 1982, which then became known as the Doherty threshold. See
response time.