Last week, Quartz’s internal chat erupted in activity when one of my colleagues in the New York office suggested putting the overhead office light settings to a group vote.
The debate raged for close to an hour, as people came and went in the chat, most expressing very strongly held opinions. In the end, there was no resolution.
Why does lighting provoke such a strong reaction? There’s no doubt that lights can have a powerful physiological effect. Mark Rea, director of the lighting research center at Rensselaer Polytechnic Institute, points out that lighting therapy can affect cancer recovery and help people with dementia sleep better and feel less depressed. But pinpointing exactly why certain light setups produce a particular effect on people is extremely difficult to determine.
“It’s a long putt from lighting to mood. There are a lot of things in between we don’t fully understand,” says Rea.
Baba Pendse, a psychiatrist who researches the effects of lighting on mental health at Lund University in Sweden, explains that light helps regulate circadian rhythms (our daily biological cycles), which in turn affect sleep, alertness, performance, and much else.
Our bodies respond to daylight by producing hormones such as cortisol and serotonin. Pendse explains that brighter light can increase the production of these hormones, which influence “mood, aggression, sexuality, appetite.”
This helps explain why, generally, dim lighting makes people feel sleepy. And we know that light exposure, particularly at night, makes you more alert. (“Bright light is like a double espresso at night,” says Rea.)
But trying to establish more precise effects is difficult, both because lighting is hugely variable, and because our response to a specific light setting often depends on many other factors.
“If I made people sit in dim conditions and try to do sewing they’d be in a pretty bad mood,” says Rea. “But is it okay to have 500 lux or 100 lux? You just can’t answer that question.”
He believes that much of our attitude to light is influenced by our innate craving for information.
“The better the lighting, the more information I can gather—whether I’m reading a paper or I’m enjoying a painting in a museum, or watching my kids play in the backyard,” he says. “If the lighting compromises our ability to acquire information, we’re probably going to be in a bad mood.”
But the same lighting won’t have the same effect on everyone, says Rea. We all have individual lighting preferences, just as we have personal food preferences.
So how to choose the optimal light setting in a big office to make the most people happy? Research shows that people are happier when they have personal control over their workspace lighting. In other words, when it comes to lighting, one shade does not fit all.