Sometimes even a healthy brain doesn’t work the way it’s supposed to.
Nobody may know that better than Rick Perry, the Texas governor, who suffered an embarrassing memory lapse during the Republican presidential debate on Wednesday. Mr. Perry stops midsentence as he struggles to remember the name of the Department of Energy, one of three federal agencies he has often said should be eliminated. A pained look crosses his face. He stammers. He starts over. He changes the subject. But the words don’t come.
How the gaffe will affect Mr. Perry’s political aspirations isn’t known. But among brain researchers, the moment is a fascinating display of a common human experience: the brain freeze.
“There are a lot of potential explanations for why it happened,” said Daniel Weissman, a University of Michigan neuroscientist who studies attention. “A lot of things are going on when we try to recall memories, and problems at any stage could lead to failure.’’
Mr. Perry is not the first public figure to suffer an embarrassing memory lapse. Earlier this year, the singer Christina Aguilera forgot the words to the national anthem as she performed at the Super Bowl. And Chief Justice John G. Roberts Jr. misplaced a word in the oath at the swearing-in ceremony for President Obama, prompting him to readminister the oath the next day.
Brain researchers note that countless memory lapses like these happen to the rest of us every day, whether it’s walking into a room and forgetting why you are there or being unable to recall a name that’s on the tip of your tongue.
Some memories, like the name of the first president or a child’s birthday, are so strong that recalling them is effortless. But when the information is relatively new or used less often, we must rely on the brain’s ability to strategically search our memory for the hard-to-retrieve information. During this process, we engage the brain’s prefrontal cortex, which interacts with the medial temporal lobe, the part of the brain that forms and retrieves memories of facts and events.
When all goes well, the medial temporal lobe acts like a library’s card catalog system, pointing to the locations in the brain where different parts of the memory are stored and allowing the memory to be recalled. But in Mr. Perry’s case, it appears that something went wrong, and the search turned up the wrong card or looked in the wrong place or was interrupted.
The culprit could have been distraction, experts say. Just before the gaffe, Mr. Perry looked directly at his opponent Ron Paul, which suggests the glance may have disrupted his train of thought. Or it’s possible that Mr. Perry’s mind may have started moving ahead to his next point too quickly, leaving him muddled in the moment. Stress also can impair the function of the hippocampus, which is also involved in memory retrieval.
“Trying desperately to fulfill the promise you made at the beginning of your utterance, then, under the bright lights, with the stakes still very high and getting higher, stress bad and only getting worse, the time late and getting ever later, grasping for straws offered to you by your competitors in a debate — the problem is only compounded,’’ Neal J. Cohen, a University of Illinois professor of psychology who studies human learning and memory, said in an e-mail exchange.
Another possibility is that Mr. Perry has had other cost-cutting conversations with his campaign strategists, and those memories were interfering with his ability to recall the details of his current plan. Such interference from past memories occurs, for example, when we leave a grocery store and stare at a sea of cars in the parking lot, realizing we have forgotten where we parked.
“As you search in your memory, there are all these very similar memories of parking at the grocery store that are interfering with each other,’’ said Dr. Weissman. “If there had been discussions of cutting other departments, it’s possible that there was somehow interference from those memories, and that’s why he couldn’t recall it.’’
Recent brain research has used functional magnetic resonance imaging scans to watch brain activity during lapses of attention during a monotonous task. The real-world equivalent would be driving along the highway, only to discover you have driven well past your exit. The research suggests that during familiar tasks, a brain region called the default mode network kicks in and the brain gets lazy.
“We think that it gets lazier — or less diligent — with respect to the external task because it thinks it knows what is going to happen next,” said Tom Eichele, a neurophysiologist and adjunct professor of biological and medical psychology at the University of Bergen in Norway.
Whether it was stress, competing memories or distraction that caused Mr. Perry’s brain freeze, it’s clear that he’s not alone.
“I thought it was a pretty everyday experience,’’ Dr. Weissman said. “We’ve all had this happen.’’