The Effect of Fading-In Light Transitions to Induce Micro-Refresh on Intellectual Work

Abstract: Enhancing intellectual productivity is a critical issue in the modern information society. Previous studies have suggested that short breaks can effectively sustain cognitive performance [1]. "Micro-refresh" (MR), a brief break of a few to several tens of seconds aimed at maintaining concentration without significantly disrupting workflow [2], can be a promising strategy. However, effective methods for inducing MR remain unclear. This study focuses on dynamic lighting changes in an office environment as a novel method to induce MR. The primary objective is to conduct a preliminary experiment to investigate whether switching between lighting environments designed for work and refreshment can induce MR and support intellectual concentration during cognitive tasks.In this study, seven university students participated in a laboratory experiment. They performed a comparison task [3] under two lighting conditions: a switch condition and a no-switch condition. In the switch condition, the lighting environment alternated through fading-in between an approximately 750 lx task-and-ambient lighting designed for concentration and a brighter, uniform ambient lighting designed for refreshment. This switch occurred for 30 seconds a 10-minute cycle. In the no-switch condition, the task-and-ambient lighting was maintained in approximately 750 lx. To assess performance, the Concentration Time Ratio (CTR), an objective measure of intellectual concentration [4], was calculated from task response times. Subjective evaluations were also collected through questionnaires assessing fatigue and concentration levels, as well as feelings of detachment and refreshment, after each task set.As a result, the CTR improved for four of the seven participants under the switch condition. The average CTR for all participants was also slightly higher in the switch condition compared to the no-switch condition. Subjective results indicated that the switch condition tended to suppress increases in fatigue and declines in concentration. Furthermore, they reported greater feelings of refreshment and a lower tendency for detachment from the task in the switch condition. Post-experiment questionnaires revealed that most participants found the lighting environment in the switching condition comfortable and the switching frequency and duration appropriate.These findings from this preliminary study suggested that dynamic lighting changed during intellectual work had the potential to enhance subjective feelings of refreshment and contribute to the maintenance of concentration. However, the effect on CTR showed considerable individual differences, and it was observed that some participants did not utilize the intended MR periods for rest. Although these results are preliminary, they are expected to provide　valuable insights for designing office lighting systems that support intellectual productivity, further validation with a larger sample size and clearer instructions regarding the purpose of MR is necessary to generalize the findings.[1] Kristin, M. F., Paul, N. R., & William, S. H. (2016) Rest improves performance, nature improves happiness: Assessment of break periods on the abbreviated vigilance task. Consciousness and Cognition, 42, pp. 277–285.[2] Kitayama, K., Dianita, O., Ueda, K., Ishii, H., Shimoda, H., & Obayashi F. (2023). Micro-Refresh to Restore Intellectual Concentration Decline During Office Work: An Attempt at Quantitative Effect Evaluation. Intelligent Human Systems Integration, 69. pp. 87–93.[3] Ueda, K., Tsuji, Y., Shimoda, H., Ishii, H., Obayashi, F., & Taniguchi, K. (2016). Development of "Comparison Task" to Measure Intellectual Concentration by Room Environment. Proceedings of the 2016 International Conference Affected on Communication and Information Systems, pp. 58–64.[4] Uchiyama, K., Oishi, K., Miyagi, K., Ishii, H., & Shimoda, H. (2014). Process in Evaluation Index of Intellectual Productivity Based on Work Concentration. Lecture Note on Software Engineering, Vol.2, No.1, pp. 21–25.

Keywords: Intellectual concentration, Lighting environment, Task and ambient lighting, Micro-break

DOI: 10.54941/ahfe1007072

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