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Got a bad memory? The brain has a unique way of helping you forget.

Say you’re on a date and you trip and fall so your dress rides up and he sees your underwear. Or your boss tells you that for the third year in the row there will be no raises. Both of these experiences feel uncomfortable, but what do you do to forget these awkward memories? Researchers found that we use two different ways -- suppression or substitution -- to avoid thinking of uncomfortable or unhappy memories.

“We assume that, in everyday life, healthy people will use a mixture of both mechanisms to prevent an unwanted memory from coming to mind,” says Roland Benoit, a scientist at the Medical Research Council, Cognition and Brain Sciences Unit at University of Cambridge, via email. “We did not know whether the processes of direct suppression and thought substitution can be isolated, and which, if any of them, would actually cause forgetting.” 

Roland and his co-author, Michael Anderson, asked 36 adults to participate in a memory exercise where half suppressed memories and the other half substituted new memories. The researchers hoped to understand how we voluntarily forget and how it affects general memory. The subjects were tested during magnetic resonance imaging procedures, or MRIs, allowing the researchers to observe how the brain works during suppression and substitution.

While both processes cause forgetting, a different region of the brain controls each one. When people suppress memories, the dorsal prefrontal cortex inhibits activation in the hippocampus, which plays an important role in retaining memories.

“It thus effectively breaks the remembering process. This, in turn, disrupts the memory representations that would be necessary for recalling the unwanted memory later on,” Benoit explains.

When it comes to substitution, the brain works a bit differently -- the caudal prefrontal cortex and midventrolateral prefrontal cortex form a network of sorts that works with the hippocampus to swap out new information with details people would soon forget.

“By just looking at how well people forgot memories, you couldn’t tell whether they had done direct suppression or thought substitution,” Benoit says. “These mechanisms are based on different brain systems that work in opposite fashion: One (direct suppression) by ‘slamming the mental break’ to stop the remembering process and the other (thought substitution) by steering the remembering process towards a substitute memory.”

Even though people exploit both to forget those nagging, unwanted memories, actively overlooking unpleasant events can negatively impact how we remember. But Benoit notes that learning how people deal with unwanted memories helps them understand how people with traumatic memories, such as PTSD sufferers, cope with remembering. 

“It is perfectly natural for people, upon encountering an unwelcome reminder, to try to put the unpleasant reminding out of mind. We all have experienced this.  Intuitively, it feels as though we solved this problem.”  

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Even state records aren't enough to deter some in their beliefs, as evidenced by this billboard.

Here’s the delicious irony of this post: Some of you will disagree with the content. Strongly. Vehemently. Passionately.

Angrily.

You are wrong, according to the facts. Yet you maintain a death-grip mental hold on some untrue myths. And you refuse to surrender your unshakable belief – even when evidence is presented to the contrary. Why? Well, it’s basically how our brains work when it comes to persuasive urban legends and fabrications that perfectly suit our worldviews, according to a new report published in Psychological Science in the Public Interest, a journal for the Association for Psychological Science. Simply put: it’s cognitively easier for our minds to trust a lie – if it supports our deepest convictions – than it is to reject information that requires some mental sweat to assess.

The report, which explains why some pieces of misinformation are so “sticky,” was authored by a cognitive scientist and three psychology professors.

Let’s jump right in, shall we?

President Barack Obama was born in the United States.

We don’t have to take Obama’s word for this. In late May, Arizona Secretary of State Ken Bennett – who has served on Republican Mitt Romney’s campaign – received state records from Hawaii. The information verified that on Aug. 4, 1961, a young woman gave birth to a baby boy in a hospital at 1611 Bingham St. in Honolulu, and that boy grew up to be elected the 44^th president. The documentation, in turn, convinced Bennett to allow the president’s name to be placed on the November ballot in Arizona.

But the doubters – “birthers” – still call it crap. This is the authors' first example of misinformation that, for some, cannot be unstuck.

“You can look at it from the point of view of the people that first raised the question: They want something that would invalidate this candidate,” said Colleen Seifert, an Arthur F. Thurnau Professor of Psychology at the University of Michigan, and one of the report’s authors. “So if it were true, they say it would be so great because it would solve this problem for them. But it’s really not true. So they keep clinging to it because they don’t have an alternative that is equally damning or that equally would change the playing field.”

Unbelievers: We are not nearly finished grinding your gears.

The report next cites two more pieces of information as incontrovertible facts: climate change is occurring and vaccines do not cause autism.

Some parents of autistic children are sure that childhood shots changed their kids’ brains. That has led other parents to become wary of inoculations.

“You can imagine (vaccines) as a cause and it fits really well with the situation because that’s when they had the shots and that’s when you started noticing your child was different,” Seifert said. “It all kind of makes sense. It’s a great package.

“But if they look at the statistics and ask themselves: Well, every child gets a vaccine, why is it only some of them would get autism from it? That has got to cause some cognitive conflict in order for those parents to recognize that and believe it’s not true,” Seifert said. “But it’s so good, it should be true. And they don’t have an alternative that would completely fit it so well."

Her research has shown that unless you can give people an alternative fact “that fills that causal hole,” they will cling to the old belief.

Sometimes, however, even cold facts won’t budge some folks off their stubborn perch. Earth is warming – and we’re doing it. Need confirmation? In late June, ExxonMobil CEO Rex Tillerson acknowledged that burning of fossil fuels is heating the planet. If an oil guy is going to own it, well, it seems sort of tough to keep your head buried in the oil shale on this issue.

Skeptics, however, call all this hot-and-bothered talk “junk science.”

According to the authors of the “sticky misinformation” report, that’s partly because the doubters all get around in vehicles.

“As you can imagine,” Seifert said, “there would be inconsistencies in their own lives: I drive a combustion car so I don’t want to admit that what we’re doing is causing harm to the earth. It’s the maintaining of this inconsistency internally – if my value is that I want to keep doing what I’m doing then anything that threatens that world view, I reject.”

Now back to even more delicate ground, the election, where this past summer Romney used Obama’s birth heritage as a stump speech quip.

If hospital records won’t quell the “birthers” – won’t, as the psychologists like to say, “fill the hole” of truth – what in the name of science will it take to satisfy them?

What will allow the president’s opponents to say, in Seifert’s words:  “Now, we’ve got something on him; he’s caught cold and it fits our view of him that he’s not fit for the presidency.”

What would that be? You already know one answer.

“A blue dress,” Seifert said, “hanging in some intern’s office.”

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