# A Study on the Impact of Blue Light and Its Brightness on Long-Term Memory
## 3 Result and Discussion  
### Experimental Results  
Descriptive statistics were performed to analyze the effect of blue light and its brightness on long-term memory, and the results are summarized in Table 1. According to the analysis results, the highest long-term memory performance was achieved under a blue light condition with a high illuminance of 1000 lux (39.6 on average and SD = 20.10). The lowest performance (25.6 on average and SD = 11.58) was observed under a red light condition with a low illuminance of 400 lux.  
Subsequently, a repeated measures ANOVA was performed in an attempt to determine the statistical significance of the effects of light color and brightness on long-term memory performance. Statistically significant differences were observed for both light brightness (F = 9.29 and \(p\) = 0.01) and light color (F = 14.58 and \(p\) = 0.01). However, there were no interaction effects between light brightness and color, as shown in Table 2.  
Post hoc tests were then performed to confirm the performance difference between each light condition in more detail. The results indicated that long-term memory performance was higher when light brightness was higher and blue light rather than red light was applied, as shown in Table 3. The difference was statistically significant, with a confidence level of 95%.  
As can be seen in Figure 4, blue light was more effective than red light in long-term memory enhancement regardless of brightness. This result coincides with those of previous studies highlighting the superiority of blue light in long-term memory activation. Meanwhile, the brighter light more effectively enhanced long-term memory performance for both blue light and red light. Despite being statistically insignificant, it was also found that long-term memory performance was higher when red light was applied in brighter environments than when blue light was applied in darker environments. This result  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Condition** & **N** & **Dark (400 Lux)** & **Bright (1000 Lux)** \\ \cline{2-4}  & & **Mean (SD)** & **Mean (SD)** \\ \hline Red light & 25 & 25.6 (11.58) & 35.2 (20.02) \\ Blue light & 25 & 32.8 (12.75) & 39.6 (20.10) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Descriptive statistical analysis results according to lighting conditions.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Sum of Squares** & **F** & \(p\) & **Partial** \\  & & & **Eta Squared** \\ \hline Brightness & 1681.00 & 9.29 ** & 0.01 & 0.28 \\ Color & 4344.00 & 14.58 ** & 0.01 & 0.39 \\ Brightness \({}^{\star}\) Color & 49.00 & 0.50 & 0.49 & 0.02 \\ \hline \hline \end{tabular} \({}^{\star}\)_p_ \(<\) 0.05, ** \(p\) \(<\) 0.01.  
\end{table}
Table 2: Results of repeated measures analysis of variance (ANOVA).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Mean Difference (I-J)** & **Standard Error** & \(p\) \\ \hline Bright (I)–Dark (J) & 8.20 ** & 2.69 & 0.01 \\ Blue (I)–Red (J) & 5.80 ** & 1.52 & 0.00 \\ \hline \hline \end{tabular} \({}^{\star}\)_p_ \(<\) 0.01.  
\end{table}
Table 3: Results of post hoc test.  
indicates that light brightness may also be an important factor that determines the effect of light on long-term memory. Therefore, when blue light is applied where long-term memory is required, its brightness should also be taken into account.