(A) Schematic representation of the proposed short-term memory experiment. This short-term memory test includes several trials, and each trial consists of two parts: 1) six numbers are presented to the user sequentially, and each number lasts for 400 ms; and 2) a number is presented to the user and the user must indicate whether or not the number had been shown before by using a mouse click. The total time of this short-term memory test was about 3 min, and the trial was repeated until the end of the testing period. (B) The experimental setup for the short-term memory test under the quiet and noisy conditions. Under the quiet condition, users were asked to take the test without any interruptions or noises. Under the noisy condition, users were asked to take the test with a randomly selected movie playing in the background on the screen and a sound playing via earphone. The sound consisted of a set of names spoken by a female voice at a random pace at 80 dB.