A brief and single session of mindfulness practice for 30-minute.

A brief and single session of self-directed relaxation for 30-minute.

Open thinking.

In the MI condition, participants were guided to focus on present experiences regarding the thoughts, emotions and sensations through the three classic mindfulness exercises (i.e., focused breathing, meditation, and body scanning). The duration of MI was 30-minutes.

The Chinese version of the State-Trait Anxiety Inventory (C-STAI, Wang & Chung, 2016), which is based on the State-Trait Anxiety Inventory (STAI, Spielberger, 1970), was utilized to assess an individual's alteration of state anxiety before and after each experimental manipulation in current study. The State Anxiety Inventory (SAI) is a 20-item sub-scales in the STAI, with a 4-point Likert scale ranging from 1 (not at all) to 4 (very much so) used for each item. Higher total scores indicate higher levels of state anxiety.

The Positive and Negative Affect Schedule (PANAS) was utilized to assess an individual's alteration of PA and NA before and after each experimental manipulation in current study. PANAS is a 20-items questionnaire that consists of two 10-item mood scales assessing the positively affective states (i.e., PA) and negatively affective states (i.e., NA), respectively. Participants were asked to rate to what extent they felt a certain way right now from 1 (not at all) to 5 (extremely). Higher total scores indicate higher intensity of affective state.

The selected frequency bands were as theta (4-8 Hz) and alpha (8-13 Hz), the frequency bands were computed by averaged across epochs and integrated spectral power, the frontal region (Fp1, Fp2, F7, F3, Fz, F4, F8) for theta power, and posterior region (P7, P3, Pz, P4, P8, O1, Oz, O2) for alpha power were selected into the statistical analysis, respectively.