The human brain is a simple piece of complex technology. It works on expectation, not perception. Similar to a computer motherboard, the brain responds predictably with a binary logic to a series of electrical impulses derived from environmental signals received via our sensory system. In other words, if “A” and “B” are present then “C” must happen next. And in our diurnal human state of existence, there is no greater environmental signal to which our brain will respond than the color of light.

Using “brain logic” the brain understands blue, bright white light as signifying a morning condition. This dictates a rousing neurohormonal chemical cascade response designed to excite, motivate, become more aware of surroundings, and setting the body up to expend energy. Environmental light signals imbued with the longer red wavelengths will give rise to the brain expecting a more relaxing evening scenario thus setting in motion a more sedentary condition.

With this state of operation, you can see how easy it is to trick the brain if you have the right conditions and the wrong circumstances. To help clarify, here’s an example of what happens when the brain expects one thing even though reality does not support the expectation: A few years ago while wandering hopelessly lost in a maze of hospital corridors, I noticed that the maintenance staff had installed different color temperature fluorescent light tubes in two wards on the same floor. One hospital corridor was lamped with a cool, blue light source while the other was bathed in a pink toned glow. So I asked the staff if they noticed the difference in the lighting between the two corridors. To my surprise, no one noticed the color difference, but all 12 participants perceived an ambient temperature shift between the two spaces. So, what was happening here? Blame it on the brain’s rule of expectation not perception. When the brain is expecting cooler ambient temperatures in spaces bathed in bright blue lighting such as found in the early morning hours, our conscious perception of the space will coincide—a few of the nursing staff reported feeling chilly and rushed while two nurses needed to wear a sweater whenever working this corridor. Under the pink toned lighting conditions (3000K), the staff reported the space to feel excessively warm and couldn’t wait to get home. There were differing conscious perceptions and resulting behaviors even though the HVAC zones were the same. All of this from the maintenance guy using the wrong light bulbs!

So why is the average healthcare design professional not aware of the impact of light on the body and brain? This question is especially relevant in light of the newly amended ADA, which compels us to provide spaces designed to support a variety of human processes and behaviors including sleep, cognition, healing, and learning. To learn how environmental signals trigger the brain to respond and about the resulting behaviors that occur, I highly encourage you to check out the latest CEU offering from Harvard University where I will explain brain logic and the process of sleep and cognition within the context of the new ADA.