I could never do two things at once very well. At first I thought it was a male thing, then wondered if it was my learning disability. I was exonerated in December, when Vanderbilt neuroscientists Paul E. Dux and René Marois and colleagues reported in Neuron magazine that the human brain is incapable of doing two things efficiently at the same time.
They call it dual-task interference. When we talk on the cell phone while driving, for example, the brain cannot process both sets of information simultaneously, so driving is less efficient and response time is delayed. Multi-taskers who aim for efficiency may be misleading themselves; there is a bottleneck in the frontal cortex.
Efficiency aside, we are overstimulating our brains and stressing our bodies. The faster our lives go, the more stress hormones such as adrenaline and cortisol get pumped into our blood. Prolonged exposure to these hormones increases our risk for hypertension, insomnia, cardiovascular problems, depression and anxiety disorders.
Stress hormones trigger a flight-or-fight response. Attention and energy are mobilized. This can feel good, because our bodies and brains are being stimulated. That’s why stimulant drugs are prescribed to help people focus. It’s also why they are abused. But for most of us, the chemical of choice is our own adrenaline.
The other morning I came into my office after a poor night’s sleep, feeling tired and concerned about whether I could function well during the day. When I turned on my computer and looked at my desk, there were about 10 things that needed my attention at the same time. A few minutes later, there were 20 more. I got through the day pretty well and felt good about my ability to do so. But what was happening inside? My body was tired and needed rest, yet my brain was able to ignore that need by pumping out stress hormones. It’s almost as though our brain were trying to trick us into not feeling what we feel.
Not everybody’s brain is the same. My grandson Sam has some behavioral and developmental traits that place him on what is known as the autism spectrum. His brain works a little differently from most. When Sam gets overstimulated, he has “meltdowns.” As a toddler, he would bang his head on the floor. With therapy, these episodes have become less dangerous and more predictable. On a recent visit, Sam, now 6, had one of his meltdowns. I watched his breathing get rapid and his face redden. Then his body became rigid and he raged about himself and everyone else, insisting he be left alone before collapsing on the floor sobbing.
A few minutes later, after allowing my daughter to hold him on her lap as he cried, Sam looked up and said: “Mommy, everything just went too fast inside my head today.”
How many of us could verbalize that feeling? Sam felt the pain of being overstimulated. We don’t. I don’t know who is better off.