4.1. Psychometric measurements
We should first point out that the psychometric task applied to Chinese participants successfully yielded an easy and a difficult version, markedly differing in the percentage of correct responses (95 vs. 74% correct). Therefore, the test, albeit a single task in each version fulfills the criterion of a speed test, where the variance is mainly in RTs, and a difficult version, where individuals differ in the proportion of correct responses. The relative independence of the speed and accuracy tasks is reflected in their low correlation (r = 0.36). Importantly, both task versions had shown sufficient to excellent reliability.