Inside Rick Perry's head during his memory gaffe

Texas Governor Rick Perry's inability to remember his own policy - the third US government agency he would eliminate if elected - during a televised debate has seriously hampered his chances at winning the White House, analysts say. Politics aside, what was going on inside his head?

Most human beings have been there: A favourite actress whose name slips from memory, or perhaps a loved one's birthday, celebrated every year, evades recall.

But most everyday memory slip-ups do not occur under the glare of the international news media while vying for the toughest job in the world alongside seven fierce competitors.

Mr Perry on Wednesday night failed to name the Department of Energy as one of three cabinet level agencies he would seek to eliminate if elected (the other two are the departments of commerce and education).

"I can't - the third one I can't," he said when challenged by debate moderator John Harwood, adding, in evident embarrassment: "Oops."

In all likelihood, the longtime governor of Texas, a major oil producing state, knew the answer somewhere in his head.

He has vowed to trim the department's budget in the past, and later in Wednesday night's debate he recovered and mentioned it by name.

Limited 'cognitive horsepower'

Rather, Mr Perry's flub was a fairly typical reaction to stress. It illustrates the potential failures of memory in high pressure situations, psychologists and neuroscientists tell the BBC.

"Once he missed naming the department of energy the first time, the stress of that event strongly impaired the neural mechanisms of memory retrieval," says John Guzowski, a professor neurobiology at the University of California at Irvine.

"There is a fine line between the amount of stress that is good for memory and that which is bad for memory."

The human mind has a limited amount of cognitive horsepower, and in stressful situations, other thoughts compete for the use of those resources, memory and cognition researchers say.

Mr Perry may have been keenly monitoring his own performance, for instance, and during the several painful seconds of the encounter he became terrifyingly aware he was making an error.

Thoughts in competition

In Mr Perry's case, he was searching his brain for the third government agency but other thought processes intruded, says Sian Beilock, a professor of psychology at the University of Chicago, who studies the interplay between cognition and stress.

"He's worrying about screwing up, and that takes away from important resources that otherwise he could use to search his memory," she says.

The individual thoughts - the department names - were competing at that moment to get out of Mr Perry's mouth like children jumping up and down to be picked for a football team, says Art Markman, a psychologist at the University of Texas, who has followed Mr Perry's career.

The first two - commerce and education - were selected while the third - energy - was not, he says.

"The first two items shoved down that third one that he wanted to pull out," says Mr Markman, author of a forthcoming book Smart Thinking: How to Think Big, Innovate and Outperform Your Rivals.

"And at the same time he's thinking about what he's supposed to say, so he has no resources around to pull out that third one."

Obstacle

Mr Perry also may have suffered from a mental block that worked almost as an active force preventing the correct information - the name - from moving to his lips, says MIT neuroscientist John Gabrieli.

When he returned to his mental search for the name "Department of Energy", he may have been dwelling out of habit on the negative consequences of the initial memory lapse, and that drew his attention away from the information he sought, says Dr Gabrieli.

"It's not the absence of information, but it's the presence of the wrong thought that's hard to clear," he says.

"Some other thought comes into your mind that's not the right one. You know it's not the right one. Once you get stuck on that thought, it's an obstacle to the information that's really in your head."

Compounding the stress was Mr Perry's reputation in the media and among voters as a poor debater, which will have meant he was under self-imposed pressure to produce a good showing on Wednesday night.

'Cicero's debate prep'

Research has shown that when people are aware of stereotypes about themselves or their gender or ethnic group, they tend to perform down to those stereotypes as if hampered by a weight, says Ms Beilock.

For example, in studies, when girls are reminded about negative stereotypes of girls' performance on maths exams just before they are to take one, they perform worse, she says.

Mr Perry should take advantage of memory-building techniques known since antiquity to help orators avoid that kind of public error, says Joshua Foer, a science writer and author of Moonwalking with Einstein, about competitive memorisation.

"If it had been Cicero up there on stage, part of his debate prep would have involved creating an image in his mind's eye of the three departments he wanted to talk about," Mr Foer writes in an email to the BBC.

"Maybe his favourite elementary school teacher standing behind a lemonade stand handing out wads of cash, while shooting lightning bolts out of his underarms. That wacky image would have reminded him he wanted to cut education, commerce, and energy."