Source: Fast Company Feb. 7, 2018;  By Katherine Schwab

“Dim lights are producing dimwits,” remarks one researcher studying the connection between light and mental acuity.

Working in an office with a lot of natural light doesn’t just make you more productive on the job and help you sleep better at night–it may also be vital to your intelligence. A new study from Michigan State University has found that spending too much time in dim areas, like poorly lit offices, could actually change the structure of rats’ brains, impacting the way they remember information and learn new things. It suggests that the quality of light in our physical environments may deeply affect us.

MSU neuroscientists studied the brains of Nile grass rats, which are comparable to humans in that they are awake during the day and asleep at night, and discovered that after exposing them to dim light over a period of four weeks, the rats lost 30% of the capacity of their hippocampuses (the region of the brain responsible for learning and memory). The dim light also impacted the rats’ performance on a spatial task.

On the flip side, rats that were exposed to bright light improved on their performance of the spatial task; and when rats that had been exposed to dim light were given doses of bright light for a month, they fully recovered the mental capacity that had been lost.

For the scientists behind the study, “dim light” means your average gray Midwestern winters’ day or normal indoor lighting. No wonder we tend to feel more mentally sluggish during the winter months.

The reduction in mental acuity due to dim light has been studied before, but how it occurs was the primary focus of the new study. The researchers discovered that when there’s dimmer light, there is less of a particular peptide in the brain that maintains the connections between neurons in the hippocampus. “Since there are fewer connections being made, this results in diminished learning and memory performance that is dependent upon the hippocampus,” says Antonio Nunez, a psychology professor and co-investigator on the study in a statement. “In other words, dim lights are producing dimwits.”

While the research was carried out on rats, it suggests that the design of the spaces we inhabit has a direct impact on the way that we think. Spending so much time in dimly lit offices could have real consequences on the brain over time, given that humans spend 90% of their time indoors. That means that designing offices so they have a large amount of natural light isn’t just a nice perk for workers. It’s a necessity for people to be their most productive and healthiest selves.

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