Yes, you can make a burger out of human stem cells - but you probably wouldn't want to

After the success of the test-tube burger, Michael Brooks answers the question on everyone in the NS offices lips: "Why not make burgers from human stem cells?"

Sometimes the NS’s offices resound with provocative questions. Last week, it was: “Why not make burgers from human stem cells?”

This is not as ridiculous as it might first seem. It would be the pinnacle of ethical carnivorous living, the only way you could eat prime meat with the full, informed consent of the donor.

It wouldn’t be cheap. The price of a burger cultured from human cells would make the €250,000 feed, created by the Maastricht University researcher Mark Post and formally presented on 5 August, look like a bargain. Human stem-cell culture for medical research is done under the most onerous safety restrictions and following strict protocols. Culturing human cells for human consumption would be just as onerous (and thus expensive) as it is for medical research because we would have to make sure there was no chance the cells could become infected by viruses or bacteria.

Eating other animals is safer simply because the pathogens that make them ill do not necessarily make humans ill. Eat your own kind and you risk unleashing all kinds of hell. That was what the BSE crisis was all about. Ingestion of ground-up cattle brains in cheap cattle feed led to an epidemic of the bovine disease. A similar phenomenon was discovered in human beings in the 1950s. The Fore people of Papua New Guinea were eating their deceased relatives in order to absorb their strength and other qualities. Enormous numbers of them contracted kuru, a disease related to BSE, which killed hundreds of them.

Yet many more Fore women and children died of kuru than men (to the point where the women accused the men of using witchcraft to destroy them). Usually, in the traditional funeral rites, the men were given the prime cuts to eat –muscle tissue –while the women and children got the brains and organs, which harboured disease in far more virulent measure. The Fore men were largely fine, so you could argue that cannibalism is not necessarily a health hazard: it’s eating the wrong bits that kills you.

The real show-stopper for the human stem-cell burger is the bit that most of the media coverage glossed over. Growing those stem cells is not a matter of scattering them in a bed of organic grass. The cells are grown in a cocktail of antibiotics and “fetal bovine serum”. This is blood drawn from foetuses that have been removed from slaughtered pregnant cows.

At about £160 (or three cow foetuses, depending on how you want to look at it) a litre, this is the most expensive part of the whole process. It is also the most distasteful. Experiencing poor mouthfeel from a burger is one thing. Knowing a cow foetus has had its heart punctured and sucked dry in order to grow the meat is quite another.

Medical researchers get through roughly half a million litres of fetal bovine serum a year because its hormones and growth factors are so essential to stem-cell growth. There are problems with it, though. The chemicals it contains can skew the outcome of experiments. In addition, the serum is extracted in a slaughterhouse, with no anaesthetic, and research shows that the foetus probably feels pain or discomfort.

The good news is researchers are looking for replacements. Human umbilical-cord blood plasma, for instance, looks like a good candidate. But considering how few of us out there would stomach a dish containing human placenta, you could bet that there’s not much of a market for any of this.

So, yes, you can have a human burger. But we suspect you don’t want one. Not really.

You are what you eat - or at least you might be. Photograph: Getty Images.

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 19 August 2013 issue of the New Statesman, Why aren’t young people working

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.