Whenever you have a sad thought, an unkind thought, or a hopeless thought—such as “I’m never going to land my dream job”—your brain pumps out a dose of chemicals that make you feel bad. On the flip side, conjure a happy, loving, or encouraging thought, and your brain gives you a blissful jolt of feel-good chemicals. Think of these ANTs as you would the ants that might bother you if you were on a romantic picnic. One ANT, like one pesky critter at your picnic, is no big problem. Two or three ANTs, like two or three insects at your picnic, become a bit more irritating. But having hundreds of ANTs, like hundreds of creepy-crawlers at your picnic, can ruin your day. These ANTs are bad news for your brain too. The first scan revealed that gratitude and healthy thinking enhanced brain function. The regions of her brain associated with mood looked calm with optimal activity. For the second scan, we asked her to focus on sad, frightening, worrisome ANTs. She imagined her beloved dog getting sick and dying. She worried about losing her job and running out of money. And she envisioned becoming homeless. Scary stuff. Her second scan showed that her brain on negativity looked vastly different from that healthy scan. In particular, two important brain regions showed a serious and concerning decrease in activity. First, it looked like her cerebellum, usually one of the most active areas of the brain, had gone on strike. Located at the back of the brain, the cerebellum is involved in motor coordination and thought organization and is essential for processing complex information. When this region is underactive, people tend to be clumsier—both in their physical movement and in their cognitive processes. Second, the activity in her temporal lobes plummeted from all that negative thinking. The temporal lobes play an important role in mood, memory, and temper control. Decreased activity here is associated with some forms of depression, as well as memory problems, dark thoughts, and even violence. When thinking happy thoughts, activity in their emotional brain cooled off, and they reported feeling better. When they focused on sad thoughts, their emotional brain fired up with more activity, a pattern that is associated with depression. These effects aren’t short term. Negative thinking effectively rewires our neural networks2, strengthening pathways in the brain to make us more likely to continue seeing the glass as half-empty. Our brain-imaging work shows that feeling bad further affects the brain, reducing activity in an area involved with self-control, judgment, and planning. This increases the odds of making bad decisions, which leads to more ANTs, which makes you feel worse. It’s a downward spiral that can take a serious toll on your well-being. The more you allow the ANTs to stick around in your head, the more likely you are to feel anxious, depressed, or angry, and the higher your chances of having troubles at work, in relationships, or at school. I told Marcus how important it is to examine your thoughts to see if they are true and if they are helping you or hurting you. Unfortunately, if you never challenge your thoughts, you will simply believe them, and the ANTs will rule your brain and ruin your life. Challenging your negativity with rational, honest thinking is a powerful tool that can improve your brain function, boost your mood, and enhance your life.
