Cross-modal interaction between temperature and light color temperature on reading comprehension

• Reading comprehension was examined at 24 °C/28 °C and 2900K/5700 K from 9 to 11AM. • The hue-heat hypothesis is supported as thermal sensation varies with light color temperature. • Reading comprehension scores did not vary significantly, possibly due to ceiling effects. • Participants reported consistent alertness and motivation across different conditions. • PMV is an important factor to determine if the hue-heat hypothesis is supported. To improve physical learning environments and explore the potential for energy savings through adjustments in lighting color, this study examines the cross-modal interactions between thermal and visual perceptions, along with their effects on reading comprehension. A within-subject experiment was conducted with 27 participants exposed to four scenarios combining two nominal room temperatures (24 °C and 28 °C) and two light correlated color temperatures (CCT) (2900 K and 5700 K) at 510 lux from 9AM to 11AM. Thermal perceptions, visual perceptions, physiological signals and reading comprehension were measured. Repeated measures two-way ANOVA results revealed that while CCT influenced participants' thermal sensations, it did not affect thermal comfort. The post-hoc analysis suggested that room temperature remained the dominant factor influencing both thermal sensation and comfort. Additionally, a significant cross-modal interaction between CCT and thermal sensations was observed. Furthermore, participants’ reading comprehension scores remained consistent across all test conditions, which might be caused by ceiling effects. Psychological attributes such as alertness and motivation, along with heart rate and heart rate variability showed no significant differences between the four conditions. Results of quiz score and time taken to finish the quizzes suggested that shifting the temperature and light color within a moderate range does not significantly impact reading comprehension, suggesting a potential of energy saving by relaxing environmental control setpoints. Additionally, decision tree models suggest that predicted mean vote (PMV), clothing insulation, and sample size influence whether the hue-heat hypothesis is supported or refuted in literature.