Fig. 5: Procedures of creative writing task.

A Creative writing task of Study 1. Participants engaged in creative writing based on three given words and input the text into the computer. The creativity scores for creative writing here were assessed in two ways: subjective and objective scoring. Subjective scoring required two raters to score on a 1–5 Likert scale across four dimensions and sum the scores of dimensions, followed by averaging the scores of the raters. Objective scoring employed global distance quantification. The text was cleaned and organized into a high-dimensional matrix of 200-dimensional word embeddings. A sliding window size of 10 with a sliding step size of 5 was set to calculate the semantic distance between adjacent windows. Finally, the average of all semantic distances yielded the global distance. B Creative writing task of Study 2. The left panel illustrates the experimental procedure for each condition for a participant. The right panel illustrates how the presentation sequence of conditions and event materials is balanced across participants. Note that participants were randomly assigned to four groups, with each participant completing 10 events of mental imagery condition’s creative writing tasks and another 10 events of semantic understanding condition’s creative writing tasks. MI mental imagery, SU semantic understanding. Icons were obtained from the open-access web-based software (ICONFONT, https://www.iconfont.cn).