Fig. 1.

Training task diagram. The training task required the participants to remember the color (red, green, yellow, or blue) and position (3 × 3 matrix) of the Color Block, and judge whether the color and position of the current block was the same as the forward nth character, in which “n” represents the working memory load. The upper part represents WMT in level 2, and the lower part represents EWM-T in level 3, in which the color squares are replaced by color faces. In each trial, the Color Block was presented for 500 ms and was followed by a blank screen presented for 2500 ms. A completed training block contained 20 + n trials. The trials targeted at color and position were randomly assigned within 4–6 trials to reduce participants' propensity to guess. The n-back level of training is adaptive to individual performance. Each training day contained 30 training blocks. The complete training program included 21 training day. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)