Fig 1.
Visuospatial sketchpad subtest.
Time course of the stimulus presentation in the visual delayed match-to-sample task. A black “+” symbol is displayed at the center of the screen for 500 ms as a reminder to the participants to pay attention. In the 4 × 4 grid, 4–9 black squares are displayed in a random order for 1,000 ms each. The participants must remember the locations of the black squares. Subsequently, the black squares disappear, and the screen remains blank for approximately 1,500 ms before the grid appears again with only two black squares. Participants must determine whether these two black squares are located in the same positions as any of the previously displayed 4–9 black squares.
Fig 2.
Time course of the stimulus presentation in the letter delayed match-to-sample task. A black “+” symbol is displayed at the center of the screen for 500 ms as a reminder to the participants to pay attention. Subsequently, a blank screen is displayed for approximately 600 ms before a letter loop appears. In a clock-like loop, 4–12 upper case letters are displayed in a random order for 1,500 ms each. After the letter loop disappears, the screen remains blank for 1,300–1,800 ms before a lowercase letter appears at the center of the screen for a further 1,500 ms. Participants must determine whether this letter was among the letters in the clock-like loop (irrespective of case). Subsequently, another blank screen is displayed for 1,000 ms, after which the task ends.
Fig 3.
Time course of the stimulus presentation in the running WM task. A black “+” symbol is displayed at the center of the screen for 500 ms as a reminder to the participants to pay attention. Subsequently, a blank screen is displayed for approximately 600 ms before a letter series appears. The letter series contains 4–12 uppercase letters that appear sequentially, with each letter being displayed for 750 ms. After the letter series disappears, three of the letters reappear at the center of the screen for approximately 1500 ms. Participants must determine whether these three letters were the last three letters of the previously displayed series. Subsequently, another blank screen is displayed for 1,000 ms, after which the task ends.
Fig 4.
Time course of the stimulus presentation in the number-size Stroop task. A black “+” symbol is displayed at the center of the screen for 500 ms as a reminder to the participants to pay attention. Subsequently, a blank screen is displayed for approximately 500 ms before two numbers appear for 100 ms each. Participants must determine which number has the higher value while ignoring the digit sizes. After another blank screen is displayed for 800–1,200 ms, the task ends.
Fig 5.
Time course of the stimulus presentation in the number-switching task. A black “+” is displayed at the center of the screen for 500 ms as a reminder to the participants to pay attention. Subsequently, a blank screen is displayed for approximately 600 ms before a number appears at the center of the screen. Each number appears for 100 ms. The participants must determine whether the values of the red numbers are higher than 5 and whether the blue numbers are odd or even. Subsequently, another blank screen is displayed for 1,000 ms, after which the task ends.
Table 1.
Descriptive statistics among observed variables for the whole sample (n = 115).
Table 2.
Correlations among observed variables for the whole sample (n = 115).
Table 3.
Accuracy differences between high- and low-score groups (%).
Table 4.
Reaction time differences between high- and low-score groups (ms).
Table 5.
EFA results for the participants’ accuracy and reaction times in the five subtests.
Fig 6.
Path model and standardized coefficients of confirmatory factor analysis.
Table 6.
Fitness of the CFA model.
Table 7.
Pearson’s correlation coefficients for WM measures and Raven’s APM accuracy.
Table 8.
Total variance explained.
Table 9.
Comparison of fitness indices between the one-factor model and original model.
Table 10.
Fit conditions of the various models.