Effect of indoor illuminance on human short- and long-term memory performance

The purpose of this study was to investigate participants’ long- and short-term memory performance under different light environments and time situations. Forty-two participants were recruited. The participants’ short- and long-term memory capacities were evaluated under the three lighting conditions (300 lx, 600 lx and 800 lx) and at two times (morning and afternoon). The results showed that different illuminance levels significantly affected participants’ short- and long-term memory capacities. In the 2-back test, participants performed better in the 800 lx environment. For the concept map test, results reported that better memory capacity was found in the 600 lx environment. Regarding the time factor, the time effect significantly affected long-term memory. Participants performed significantly better in the morning than in the afternoon across all tasks. The final results were obtained using the response surface method. The 800 lx illumination combination in the morning was optimal for both short-term and long-term memory performance. In conclusion, the main finding is that participants’ long-term and short-term memory capacity varied depending on the lighting conditions, with illuminance significantly affecting both short-term and long-term memory. The results might have implications for future lighting research as well as lighting design for memory capacity work needs.