Evaluation of Changes in Psychophysical Performance during the Afternoon Drop off in Work Capacity after the Exposure to Specific Color of Light

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Summary

White light enriched with red wavelengths (WRL) improved speed, accuracy, and subjective performance in younger workers (22–34), while blue-enriched white light (WBL) reduced errors and response times in older workers (55+) during the afternoon performance dip. These age-differentiated responses suggest that spectral tuning of workplace lighting should account for worker age to optimally counteract circadian-driven productivity losses in the early afternoon.

Key Findings

WRL exposure in 22–34 age group increased number of correct responses, improved work speed, decreased errors, reduced boredom, and raised subjective performance ratings
WBL exposure in 55+ age group decreased number of mistakes and reduced response time during afternoon performance dip
Study conducted on 50 subjects using Grandjean Scale, Attention and Perceptiveness Test (TUS), and GONOGO test across three lighting conditions: reference white, blue-enriched white, and red-enriched white
Both blue and red spectral enrichment of white light were effective at increasing psychophysical performance, consistent with prior international research

Categories

Workplace Performance: Study directly measures alertness, attention, speed, and error rates under different colored lighting conditions during afternoon work capacity dip.

Sleep & Circadian Health: Investigates the afternoon circadian dip in work capacity and how spectral composition of light modulates arousal during this period.

The Science of Light: Examines the differential effects of blue-enriched and red-enriched white light spectra on psychophysical performance across age groups.