How LEDs are Changing Human Behavior

natural low light LEDs.

According to Richard J. Wurtman, a nutrition professor at MIT,

“Light is the most important environmental input, after food, in controlling bodily function.”

This belief that lighting has strong powers over the human mind and body is nothing new. Since ancient Greece, Mystics have used color therapy, believing that manipulations of light and color could cure illnesses. Color therapy was always written off as a pseudoscience up until recent years. Researchers have begun exploring the science behind light and its impact on man. The scientific study of light and its influence on human psychology/physiology was termed “photobiology” in order to distance itself from its mystical predecessor. The field has risen in popularity since its inception in the 1940s, but the science behind it is nothing new:

The Circadian Rhythm.

Humans evolved to naturally align with the 24-hour cycle of the Earth. Hunter-gatherers experienced 8 hours of bright sun and blue sky followed by dusk, moonlight, and dawn. Our bodies produce various neuro-chemicals throughout the day that control our sleep and wakefulness. This 24-hour pattern is known as the circadian rhythm. Nowadays, however, we’re subject to roughly 16 hours of artificial light that makes no attempt to replicate the natural light variations our body expects us to receive. Our circadian rhythm suffers because there are no environmental cues that tell the body what time it is.

We’ve reached the point in LED technologies that we can return to our natural circadian rhythm and actually maximize the effects light has on our body. Photobiologists experimenting with light and color conditions have found they can enhance mood and day-to-day productivity by imitating the sun’s natural light emissions. For example, research shows warmer lighting correlates to an increase in melatonin, a hormone established in the circadian rhythm as the relaxation hormone. This makes sense as the sun dims around dawn, becoming a much more vibrant yellow color.

The Empirical Evidence:

A prison corridor dimly lit at night by various harsh LED lights.

Photobiologists implement lighting solutions in workplaces, classrooms, and prisons with astounding results.
Research in HM Prison Ashfield England found that warmer lights in the inmates’ cells reduced the amount of vandalism. Even more crucially, the prisoners’ anti-social tendencies decreased. Another study in the San Bernardino County Probation Department in California used color therapy to soothe children when they became violent. Children were immersed in a bubble gum pink cell. Paul Boccumini, director of clinical services for the department, found the children tended to relax, stopped yelling and banging, and often fell asleep.

Professor Harold Wohlfarth of the International Journal of Biosocial Research conducted a classroom study with a noisy room of children (Volume 3, No. 1). Wohlfarth replaced the fluorescent lights with full-spectrum LED lighting. He repainted the white and orange walls to a light blue. Lastly, he replaced the orange rug with a gray carpet. As a result, Wohlfarth reported the children’s mean systolic blood pressure dropped from 120 to 100. According to the teachers and independent observers, when the classroom was changed, students became less fidgety and more attentive. When the room returned to its original design, readings gradually increased once again.

bright, full-spectrum LEDs overhead.

Psychology or physiology?

Photobiologists all acknowledge that lighting and color interact with humans to change behavior, but they disagree about why there’s a change in the first place. Is it psychological or physiological? Most lighting studies in the past decades were psychological, focusing purely on the behavioral changes. A prime example of a psychological experiment is London’s Blackfriars bridge being painted blue to deter people from jumping.

A human skeleton with its nervous system outlined in purple

Meanwhile Professor Wohlfarth, president of the German Academy of Color Science and a photobiologist at the University of Alberta, argues that “color very definitely has a physiological effect.” Two blind children were present at the Elves Memorial Child Development Centre during a classroom lighting experiment. Wohlfarth found the same changes in blood pressure, pulse, and respiration rates across the entire classroom.

Several hypotheses exist explaining the bizarre effects of light. The electromagnetic energy that composes light is believed to affect one or more of the brain’s neurotransmitters. These chemicals carry messages from nerves to muscles along the parasympathetic nervous system. This system controls many basic body functions and emotional responses, such as aggression.

LEDs Today

Our LED lighting infrastructure will only continue to evolve. Full-spectrum LED lights are already on the market, and it’s only a matter of years until we see temperature changing bulbs that correlate to the time of day. Until then, it’s important to stay conscious about your environment. Next time you catch yourself in a productivity slump at work, recognize it’s probably because your body needs to realign its circadian clock. Spending a couple of minutes under natural sunlight will prepare you for the rest of the day. Awareness is the best combatant to a draining light system. Stay conscious and you’ll be working under natural sunlight technology in no time.

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