People who don’t forget can still be tricked with false memories

Despite being able to remember minute details from every moment of their lives, the ability to never forget has other costs for some people.

“Time is the thief of memory,” wrote Stephen King in one of his many books. For some people, however, that is not true. They are gifted with what scientists call highly superior autobiographical memory (HSAM), which means they can remember in vivid detail every day of their life going back to childhood. But new research shows that even these special people are susceptible to forming false memories, sometimes more than normal people.

The first study of a person, later identified to be Jill Price, with this special ability was published as recently as 2006. Since then the database of HSAM individuals in the US has grown to about 30 people. It includes people like Bob Petrella, who can recall the date he met every one of his friends and acquaintances. Or Brad Williams, who can remember both what he did on any day and what significant world events occurred.

James McGaugh at the University of California Irvine was the author of the 2006 study, and for the past seven years he has been working to understand what makes HSAM individuals so special. A 2012 study showed, for instance, that HSAM individuals have different brain structures. They posses more white matter in areas linked to autobiographical memory. But because there are so few of them “we still don’t know enough to be able to draw robust conclusions”, says Martin Conway, a cognitive psychologist at City University London.

Knowing how HSAM people form memories would be a great leap in our understanding. With graduate student Lawrence Patihis, McGaugh set out to fill that gap. One way to do that would be to test if HSAM individuals are susceptible to false memories. After all, memories are easy to distort. It happens to everyone: the young, the old, the intelligent and the dumb. Now, in a study just published in the Proceedings of the National Academy of Sciences, Patihis finds that HSAM individuals too can be tricked to possess false memories.

Not so perfect
For the study, Patihis recruited 20 out of the 30 known HSAM individuals in the US. They were matched, by sex and age, with 38 people with normal memory. All of the participants were then given three tests.

In the first test, each participant was shown a series of words that were all supposed to be connected to a “lure word”. So if the lure word was “lamp” then they will be shown words like light, table, shade and stand, but not the word lamp. After they have seen the list, they are asked if they saw the word lamp. People with normal memories got the answer wrong seven out of ten times. HSAM individuals too got it wrong just as much.

The second test was more elaborate. It showed a slideshow of photos depicting a crime. After 40 minutes, they were then shown words describing the crime with misinformation sprinkled in them. Then 20 minutes later they were tested to see how many people believed the misinformation to be true. This time HSAM individuals did worse than normal people. They were 73 percent more prone to false memories. “Maybe HSAM individuals form richer memories through absorption of more information and that is why they are also more susceptible to false ones too,” says Patihis.

Perhaps it is easy to manipulate recent memories. So in the third test Patihis looked to test long-term memory. All participants were asked to recall the September 11 terrorist attacks. They were then given irrelevant facts about that event, one of which was not true (someone captured the footage of United 93 in Pennsylvania). After 15 minutes, all participants were then asked whether they had see such a footage. Like the first test, normal people and HSAM individuals performed almost equally badly on this test.

“This shows that maybe people with superior memories form them just like normal people. Thus, in the process, they are also prone to making the same mistakes,” says Patihis. Equally, they may use a different process of forming superior memories, but one that has same problems as that of the normal process.

There is still contention among experts whether HSAM individuals are “special”. K Anders Ericsson of Florida State University says, "our work has pretty much concluded that differences in memory don’t seem to be the result of innate differences, but more the kinds of skills that are developed." To which McGaugh says, “you’d have to assume that every day they rehearse it ... The probability of these explanations dwindles as you look at the evidence."

Price had admitted that remembering everything meant bad memories were always around to trouble her. It led researchers to believe that such superior memory may come at a cognitive cost of lost abilities, or less happier lives. But research since has shown that not to be the case. HSAM individuals tend to have similar lives to normal people. With the latest study, McGaugh has shown one more task where HSAM individuals are normal. They too may be made to believe that as a kid they were lost in a shopping mall, even if that isn’t true.

This article was originally published at The Conversation. Read the original article.The Conversation

Some people have no need for post-it notes. Photo: Bala Sivakumar/Flickr
Alan Schulz
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An Amazonian tribe is challenging scientific assumptions about our musical preferences

The Tsimane’ – a population of people in a rural village in Bolivia – are overturning scientists' understanding of why humans prefer consonant sounds over dissonant ones.

It was 29 May 1913. Hoards of Parisians packed out the newly-opened Théâtre des Champs-Élysées. Messrs Proust, Picasso and Debussy were in attendance. Billed for the evening was the premiere of Le Sacre du PrintempsThe Rite of Spring, a ballet and orchestral work debuted by Russian composer Igor Stravinsky.

The attention and conjecture focused on the theatre that day meant expectations were high. However, within moments of the piece beginning, all preconceived notions held by the audience were shattered, as what was unfolding in front of them was a musical tragedy unlike anything they had ever witnessed.

A bassoon hummed into the ether before ballet dancers stomped on stage; the music, unpredictable with its experimental edge, drove forth the onstage narrative of a young girl whose selection during a pagan ritual saw her sacrificially dance towards death. Stravinsky’s composition and the ensemble of the night caused the room to descend from laughter and disruption to chaos and uproar.

The employment of dissonance – sharp, unstable chords – largely contributed to the audience’s disturbed reaction. Dissonant chords create a tension, one which seeks to be resolved by transitioning to a consonant chord – for example an octave or perfect fifth. These musical intervals sound far calmer than the chords which riveted the audience of The Rite of Spring.

Dissonant and consonant intervals find themselves as binary opposites; the frequencies at which notes played together vibrate determine whether an interval is consonant or dissonant. Consonant intervals have simple mathematical relationships between them, but greater digression from that simplicity makes an interval increasingly dissonant.

It’s long been believed  both experimentally and anecdotally – that the preference among Westerners for consonant chords highlights a universal, perhaps biologically-rooted, leaning among all humans towards consonant sounds. If you were present at the introduction of Stravinsky’s The Rite of Spring on that night of furore in Paris, you’d find it hard to disagree.

There is, however, a growing movement against this consensus. Ethnomusicologists and composers alike argue that favouring consonance may just be a phenomenon that has evolved from Western musical culture. And following the visit of a group of researchers to a remote Amazonian society, these claims could well be grounded in scientific evidence.

Led by Josh McDermott, an MIT researcher who studies how people hear, the group travelled to a village in the Amazon rainforest called Santa Maria. It’s populated by the Tsimane’ – a group of native Amazonians whose rural abode is inaccessible by road and foot, and can be reached only by canoe. There are no televisions in Santa Maria and its inhabitants have little access to radio, meaning exposure to Western cultural influences is minimal.

The researchers were curious to see how the Tsimane’ would respond to music, in order to determine whether they too had a preference for consonant sounds over dissonant ones. To everyone’s surprise, the Tsimane’ showed no preference for consonance; the two different sounds, to the Tsimane’ at least, were equally pleasant.

Detailing their research in a paper published by Nature, the group explains how the Tsimane’ people’s indifference to dissonance is a product of their distance from Western culture and music, removing any purported notion that humans are hard-wired to praise perfect fifths and fourths.

McDermott tells me that the Western preference for consonance may just be based on familiarity. “The music we hear typically has more consonant chords than dissonant chords, and we may like what we are most exposed to,” he says. “Another possibility is that we are conditioned by all the instances in which we hear consonant and dissonant chords when something good or bad is happening, for example in films and on TV. Music is so ubiquitous in modern entertainment that I think this could be a huge effect. But it could also be mere exposure.”

To fully gauge the Tsimane’ responses to the music, 64 participants, listening via headphones, were asked to rate the pleasantness of chords composed of synthetic tones, and chords composed of recorded notes sung by a vocalist. At a later date, another 50 took part in the experiment. They had their responses compared to Bolivian residents in a town called San Borja, the capital city La Paz, and residents in the United States – locations selected based on their varying exposures to Western music.

What made the Tsimane’ particularly interesting to McDermott and his group was the absence of harmony, polyphony and group performances in their music. It was something the researchers initially thought may prevent an aesthetic response from forming, but the worry was quickly diminished given the Tsimane’ participants’ measure of pleasantness on the four-point scale they were provided.

Unsurprisingly, the US residents showed a strong preference for consonance – an expected preference given the overrunning of Western music with consonant chords. Meanwhile, the San Borja and La Paz residents demonstrated inclinations towards consonant sounds similar to the US residents. The implication of these results – that consonance preferences are absent in cultures “sufficiently isolated” from Western music – are huge. We most probably aren’t as polarised by consonance and dissonance as we assume; cultural prevalence is far more likely to have shaped the consonant-dominant sounds of Western music.

McDermott raised the question about why Western music may feature certain intervals over others to begin with:

“One possibility is that biology and physics conspire to make conventionally consonant and dissonant chords easy to distinguish, and so that distinction becomes a natural one on which to set up an aesthetic contrast even if the preference is not obligatory. We have a little evidence for this in that the Tsimane' could discriminate harmonic from inharmonic frequencies, which we believe form the basis of the Western consonance/dissonance distinction, even though they did not prefer harmonic to inharmonic frequencies.”

There has been some criticism of this. Speaking to The Atlantic, Daniel Bowling from the University of Vienna said:

“The claim that the human perception of tonal beauty is free from biological constraint on the basis of a lack of full-blown Western consonance preferences in one Amazonian tribe is misleading.”

Though the results from the Amazonian tribe demonstrate a complete refutation of previous assumptions, people's musical preferences from other cultures and places will need to be analysed to cement the idea.

With research beginning to expand beyond WEIRD people – those from a Western, Educated, Industrialised, Rich and Democratic background – the tastes in music of people the world over may continue to surprise, just as the Tsimane’ did.

The Rite of Spring, which was met with ridiculing reviews has now been canonised and is considered to be one of the most important pieces of music of the twentieth century. A Tsimane’ crowd on that tender night a century ago in Paris may have responded with instant praise and elation. With further research, the imagined Bolivian adoration of a Russian composer’s piece in the French city of love may prove music to be the universal language after all.