Hi, I'm Elliott and this is Mental Floss video. Today I'm gonna talk about some misconceptions about human memory.

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Misconception number one: Memories are pretty accurate.

It often surprises people how inaccurate memories can be. Tons of different types of memory errors have been observed over the years. People commonly misremember events or even remember events that never happened at all.

An interesting study on memory accuracy was conducted in the 80s. You probably know that in 1986, a US space shuttle known as The Challenger exploded. It was huge news at the time.

The next day a cognitive psychologist gave one of his classes with over 100 students a questionnaire about where they were when they heard the news. Two and a half years later, he got in touch with around half of them and gave them the same questionnaire.

The psychologist ranked their accuracy on a scale of seven. On average, students got less than three on the scale. 25% received a score of zero.

But what if you're really sure you remember something? Well, that brings me to:

Misconception number two: If you're confident in a memory, it is likely to be accurate.

Going back to The Challenger study I just described, the psychologist also had the students rank their confidence levels for memory accuracy in the second questionnaire. The average ranking was 4.17 out of 5, but as you'll remember (maybe) many of their memories were completely inaccurate.

The conductor of the study wasn't able to find a relationship between confidence and accuracy.

This phenomenon is proved to be a major problem in court cases. A single eyewitness to a crime being very confident can sway a jury. Now that we have DNA testing, some crimes are being revisited. And according to one group that examined 239 overturned convictions, 73% of them were originally convicted due to eyewitness testimony.

That is very scary.

Misconception number three: Memories don't change.

Actually, our memories are very suggestible. Just remembering an event can cause the memory to change.

Neuroscientists believe that in the event someone recalls over and over again is more likely to change than one they don't typically recall.

So that explains why so many of The Challenger memories were inaccurate. Similar phenomenons have been observed when people "remember" the events of 9/11 or JFK's assassination. Every time we tell a story about a monumental day like one of those, our memories might pick up new emotions and feelings, which can easily change a memory.

Misconception number four: Forgetting is a gradual process.

If a memory has been stored properly, then this is true. Forgetting happens in a gradual way. But according to a few studies, the majority of experiences and learned information are forgotten just *snap* immediately.

Misconception number five: Repressed memories are common.

If you watch a lot of movies, you might think that someone repressing a memory then remembering it all later is a prevalent phenomenon. But the concept of repressed memories remains controversial in the field of psychology.

Most studies on the topic have concluded that if a person experiences something traumatic during childhood, they are very unlikely to forget that event.

According to the American Psychological Association, more research needs to be done and their website declares, "Experienced clinical psychologists state that the phenomenon of a recovered memory is rare (e.g., one experienced practitioner reported having a recovered memory arise only once in 20 years of practice)."

That brings me to:

Misconception number six: There's no such thing as a false memory.

One of the reasons that repressed memories are so controversial is because false memories do exist. There have been many studies in which researchers are able to basically implant memories in participants' minds just by asking leading questions.

You might think that you're an exception to this rule, but according to a 2013 study published in the proceedings of the National Academy of Sciences, every single person has false memories.

To prove this, the researchers gathered 20 people with highly superior autobiographical memory and 38 people with average memories. In both groups, somewhere around 20% of people recalled seeing video footage of the United Flight 93 crash on the news.

There is no such footage.

Further tests showed that each individual in the study had false memories.

This is also how Jimmy Kimmel makes his living.

Misconception number seven: Some people have a photographic memory.

Many studies have shown that there's no such thing as a photographic memory. 2-15% of children have what's called an eidetic memory, which is as close as we can get.

These kids are able to maintain a very accurate memory of an image for up to a couple minutes, but that skill soon goes away and adults rarely have eidetic memories.

Misconception number eight: Aspartame causes memory loss.

There's been a rumour going around for decades that the artificial sweetener aspartame can cause memory loss, but the US Food and Drug Administration had approved aspartame for the market, which is why it can be found in things like Nurtisweet and Equal.

The FDA has been monitoring this substance since the 70s. In 2006, they put out a statement claiming they examined over a hundred studies on aspartame and still consider it safe for consumption.

Which is great news for all you low-carbers out there.

Misconception number nine: We have a long list of memories that we just add to.

Actually, as we learn from Inside Out, forgetting old memories and information can help us learn new stuff.

In 2011, researchers at the University of Illinois in Chicago found that people were better at memorizing a list of words when they were instructed to forget half the words. According to Ben Storm, who conducted the study, "We need to be able to update our memory so we can remember and think about the things that are currently relevant."

Misconception number ten: Hypnosis can help us remember forgotten memories.

We're finishing up with another controversial one. *phew!* It's almost like memories are complicated or something.

So, studies have shown in people who are highly hypnotizable, being in a hypnotic state affects their brain in the same place that's connected to memories.

The issue is that some studies have also correlated hypnosis with false memories. Plus, people who have been hypnotized tend to be more confident in their false memories.


Thanks for watching Misconceptions on Mental Floss video. If you have a topic for an upcoming misconceptions video that you would like to see, just leave it in the comments. And we'll totally check it out.

I'll see you next week. Bye.