Effect of illuminance uniformity on paper-based reading performance: a pilot study

Abstract: Previous studies had already evaluated the effect of illuminance and correlated color temperature (CCT) on reading performance. However, the influence among uniformity of illuminance, illuminance, and CCT had not been closely taken into account. Therefore, the aim of current study was to investigate how a particular trait of lighting conditions affected reading performance. The indoor lighting environment was conducted with two uniformity of illuminance and two light conditions (400 lx, 3000 K and 1000 lx, 5000 K). A 10-minute-long paper-based reading task was carried out for each subject and the brain activities were recorded by electroencephalogram (EEG). During the reading task, each subject was asked to find out the incorrect characters and grammatical errors in the manuscript, and the reading performance was evaluated by signal detection theory (SDT) in terms of correct rate, missing rate and false alarm. Each of the 15 subjects experienced the trial for four times, under different illuminance uniformity, illuminance and color temperature each time. EEG analysis composes of 6 electrode placements, including Fp1, Fp2, F3, F4, O1 and O2, because they detected the activities of frontal lobe and occipital lobe that were closely related with information integration, error correction and visual signal processing. The frequency bands included Theta（4－7Hz），Alpha（8－13Hz）and Beta（14－30Hz） . The results showed that the participants tended to correctly detect more errors in paragraph under high illumination uniformity of the surrounding environment. It could be inferred that as the illuminance uniformity increased under the same illuminance and correlated color temperature, reading performance was improved. Moreover, the lighting conditions of 400lx, 3000K and 1000lx, 5000K in this experiment showed different results. The lighting condition of 400lx and 3000K showed that a more concentrated illumination in the center made subjects achieve better performance than a more uniform illumination in the periphery at low illumination levels did, which might be the reason for the more significant spotlight effect under this exposure condition. According to the results, this study might inspires the design of indoor lighting in workplace so that working efficiency and quality could be further improved.

Keywords: Illuminance Uniformity, Illuminance, Cct, Eeg, Reading Performance, Signal Detection Theory

DOI: 10.54941/ahfe1001159

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