A COMPARATIVE STUDY OF EMOTIONAL STATES AND WORK PERFORMANCE AMONG OFFICE EMPLOYEES UNDER DIFFERENT CORRELATED COLOR TEMPERATURES OF LIGHTING: A CASE STUDY IN AN INDUSTRIAL FACTORY IN RAYONG PROVINCE, THAILAND

Abstract

This study aimed to compare the effects of different correlated color temperatures (CCTs) on mood states and work performance among office employees. The participants were 25 office employees. A repeated-measures design was employed, comparing the participants’ original lighting condition, which was designated as the baseline condition, with three controlled lighting conditions of 3000K, 4000K, and 6500K at an illuminance level of approximately 400-500 lux. Mood states were assessed based on positive and negative mood scores, while work performance was evaluated based on the time required to complete a 350-word typing task and the number of typing errors. Data were analyzed using one-way repeated-measures analysis of variance (RM-ANOVA), followed by Bonferroni-adjusted pairwise comparisons. The results showed that lighting conditions had significant overall effects on positive mood, negative mood, task completion time, and the number of typing errors. The 6500K condition produced the highest mean positive mood score and the lowest mean negative mood score, whereas the 4000K condition resulted in the shortest mean task completion time and the lowest mean number of typing errors. Significant pairwise differences in the number of typing errors were found between the baseline and 4000K conditions, between the baseline and 6500K conditions, and between the 3000K and 4000K conditions. These findings indicate that the effects of CCT may vary depending on the outcome being assessed. Under the conditions of this study, 4000K showed a favorable pattern for work performance, particularly typing accuracy, whereas 6500K showed a favorable pattern for mood states.

Keywords: Correlated Color Temperature, Lighting Conditions, Mood States, Work Performance, Office Employees