Certain activities are known to lower our cognitive abilities. No one is going to score their best on an intelligence test after a few shots of tequila or hits from a bong. Slamming your head repeatedly against a wall is not expected to improve thought processing, either.
But there are also some lesser-known factors that decrease brainpower. Some of these activities only impair intelligence temporarily, while others have been proven to have long-term effects.
10 Dim Lighting
Researchers at Michigan State University have discovered a link between dim lighting and a diminished ability to remember and learn.
Scientists studied the brains of a group of Nile grass rats. Like humans, Nile grass rats are active during the day and sleep at night. At the beginning of the study, the rats were trained to find their way through a maze. Then they were split into two groups, with half of the rats being exposed to bright light during the day and the other half being exposed to dim lighting.
After four weeks, the rats exposed only to dim lighting had lost 30 percent of capacity in the hippocampus, which is crucial to learning and memory. In addition, all the rats were reintroduced to the maze on which they had previously trained. The rats exposed to dim lighting performed worse than they had originally, while the rats exposed to bright light showed significant improvement.[1]
The dim lighting used in the study is similar to typical indoor lighting found in most home and office settings.
9 Smartphones
Smartphones keep us in constant contact. As a result, our cognitive abilities suffer.
Researchers at the University of Texas studied a group of approximately 800 smartphone users. Participants were asked to take a series of computer tests that required their full attention. Some were asked to leave their phones in another room, while others were simply asked to mute their devices and place them facedown on their desks. Those who left their phones in another room performed significantly better on the tests than those who had their phones right next to them.
Researchers concluded that having a phone within view reduces a person’s ability to focus and perform tasks. People are so accustomed to checking their phones that their subconscious has to work against that when they are trying to focus on something else.[2]
This effort to avoid focusing on the phone depletes the energy and attention that is actually concentrated on the task at hand. Removing the phone completely gives the subconscious a break from fighting off the urge to check for new texts or emails.
8 Processed Food
A poor diet early in life has been shown to have a negative impact on cognitive performance. Researchers examined the eating habits and intelligence levels of approximately 14,000 young children. Kids who were fed mainly processed foods at age three had lower average IQs five years later than kids who ate diets rich in vitamins and nutrients.
A diet high in vitamins and nutrients helps to encourage optimal brain development, while processed foods do not. Since the brain grows at its fastest rate during the first three years of life, the nutrition supplied during this time has a lasting impact on overall brain function.
In kids who had been fed mostly processed foods at age three, dietary improvements made later in life did little to improve their associated intelligence scores.[3]
