Experiment procedure
confusion, tiredness
Before the experiment started, participants signed an informed consent form which detailed the experiment procedure, data privacy protection measures, and participants’ rights. As shown in Fig. Procedure of the experiment.The facilitator then guided each participant to become familiar with the experiment procedure through a practice block that included a sample English text (different from the nine passages used in the formal experiment) and BGM which was selected by the authors and consistent across participants. It should be noted no data were collected from the practice block. After practice, the formal experiment began. It consisted of three blocks, each of which contained three English passages with one in each difficulty level (c.f., Table Right before participants started a reading block, the eye tracker was calibrated to track the movement of participants’ dominant eyes. Before they started each passage, drift correction with the eye-tracker was performed to ensure the eye-tracking data were accurate. During reading, the BGM group read with participants’ self-provided music playing in the background, while for the Silence group, the background was in silence. All participants were asked to memorize as much of the passage’s content as possible, since they were not allowed to return to the passage once they entered the question answering stage. Upon completing a passage, three metacognitive questions on engagement, difficulty, and understanding were presented in sequence, followed by two MCQs (one text-based; the other inferential) testing passage comprehension accuracy. As the metacognition questions were about passage reading, they were presented right after the passages to avoid possible confusion of the participants. To ensure the question answering conditions in the two groups were comparable, music was paused for the BGM group during answering the questions. There was no time constraint when participants read or answered questions. After submitting answers to the MCQs, the next passage started. Meanwhile, the music resumed for the BGM group. Upon completing a block, participants were given a 2 min break to allay possible tiredness.After completing all three blocks of reading tasks, participants took a two-back test which aimed to measure their working memory capacity. An exit-interview was then conducted to elicit their thoughts and feelings on studying with BGM and experiences in the experiment, with example questions asking “How do you like studying with music in the background? Why or why not?” and “What do you think about this experiment?”. It is noteworthy that the participants did not know whether they were in BGM or Silence condition until the experiment was completed. The experiment lasted 100-120 minutes in total. At the end of the experiment, each participant was paid a nominal remuneration of about 20 US dollars.