Just A Theory

Ever suffered from a limp wrist, or been on the receiving end of a painfully iron grip? Car manufacturer Chevrolet know all about the importance of a good handshake, which is why they’ve developed a complex mathematical equation for their new staff training guide, as that well known science journal the Daily Mail reports.

It’s been a while since I covered this kind of dodgy maths, so let’s go over the basics. “Formula for” stories are seen by PR agencies as a great way to get free press coverage for whatever product they are shilling because the equations can be dressed up as real research. Attaching a “Dr” or “Prof” to your news story is a great way to gain legitimacy, and the media lap it up as another example of what those crazy boffins are up to.

While this is all great for the PR agencies and their clients, it’s terrible for science. These formulas tend to be based on extremely dodgy assumptions and contain variables which can’t be objectively measured. What’s worse, even a simple mathematical analysis usually reveals problems such as division by zero, which can lead to things like cold and lumpy but infinitely perfect pancakes.

With these problems in mind, let’s take a look at the formula for the perfect handshake. It was created by Geoff Beattie, head of Psychological Sciences at the University of Manchester, and is detailed in this the press release:

I’ve broken it over two lines because the thing is so long, and I think that square root is meant to cover the entire equation, not just the first term, but the press release isn’t very clear. We’ve also got a definition for the many variables, along with what I assume is their optimal values:

(e) is eye contact (1=none; 5=direct) 5;
(ve) is verbal greeting (1=totally inappropriate; 5=totally appropriate) 5;
(d) is Duchenne smile – smiling in eyes and mouth, plus symmetry on both sides of face, and slower offset (1=totally non-Duchenne smile (false smile); 5=totally Duchenne) 5;
(cg) completeness of grip (1=very incomplete; 5=full) 5;
(dr) is dryness of hand (1=damp; 5=dry) 4;
(s) is strength (1= weak; 5=strong) 3;
(p) is position of hand (1=back towards own body; 5=other person’s bodily zone) 3;
(vi) is vigour (1=too low/too high; 5=mid) 3;
(t) is temperature of hands (1=too cold/too hot; 5=mid) 3;
(te) is texture of hands (5=mid; 1=too rough/too smooth) 3;
(c) is control (1=low; 5=high) 3;
(du) is duration (1= brief; 5=long) 3.

Both the formula and its variables are looking really dodgy. I’ve literally no idea what terms like {(4<c>2)(4<du>2)}² are meant to mean. I can only think that the angular brackets denote some kind of average, but then why do they only apply to some of the variables? Are those 2s actually meant to be ²? In which case you can rewrite the whole term as (2<c><du>)⁴, which is at least a little bit simpler.

I also take issue with using two letters to stand in for one variable, because they can be confused for two separate variables multiplied together. Measuring “verbal greeting” and “vigour” doesn’t mean that both of your variables have to start with a v – real mathematical equations make extensive use of Greek letters in an effort to solve this exact problem. But even if this equation was beautifully formatted, it would still be rubbish.

All the measurements are completely subjective, and the scales of 1 to 5 indicate the data behind the equation was probably collected from a survey. This even includes variables such as temperature, which can easily be measured scientifically. Remember, subjective measurements are one of the hallmarks of a “formula for”.

I emailed Beattie yesterday to ask how the formula was created, but as he is yet to reply I can only speculate. I think what he has done is ask people a bunch of questions about handshakes, and then tried to fit their answers to some kind of least-squares model, as indicated by the squares and square root in the formula. This method gives you a great equation for “explaining” the data you’ve gathered, but doesn’t necessarily tell you anything about the phenomena you’re examining.

If that is the case, I still don’t understand how the formula is meant to work. You’d expect that the perfect handshake would have a maximum value of PH, and since there is no division or subtraction involve, that just means slotting in the maximum values for all your variables. The optimal values in the press release include a few 3s and 4s though, so PH isn’t going to be maximum. Hmm.

As with all “formula for” stories the maths behind the perfect handshake formula just doesn’t add up, yet it’s being interpreted as a serious piece of research. Comments on the Mail story such as these two show just how much damage this can do to people’s impressions of science:

“So, most of the country is out of work desperately trying to survive and these idiots are getting paid, what – to study handshakes? Sack these people immediately!”

How much time did the nutty professor spend on this useless bit of information?

Mathematical models and equations are a fantastical tool for understanding the natural world around us, but they have to be based on sound assumptions and decent science – things that “formula for” stories such as this almost invariably lack.

Exciting news today: I’ve been shortlisted for the Association of British Science Writers Best Newcomer award. What’s more, I’m joined by my fellow Just A Theory blogger Colin Stuart, along with Helen Thomson, the biomedical news editor at New Scientist.

It’s a great honour to make the cut, and I’m really looking forward to the award ceremony on 23 July. I’ve been working as a freelance science and technology writer for nearly a year now, and I put at least part of my success down to the many hours spent working on this very blog.

Unfortunately posting levels have died down recently, but that’s because I’ve been very busy elsewhere. Here are some of my recent articles, if you haven’t already seen me spamming them on Twitter:

Proof at last for Boltzmann’s 140-year-old gas equation – New Scientist

Drinking coffee doesn’t make you more alert, caffeine study reveals – The Guardian

First replicating creature spawned in life simulator – New Scientist

Michael Grätzel: Give people access to cheap solar power – The Observer

Wikipedia may be your first choice for trivial information, but would you trust it with your life? Surprisingly, researchers from Pennsylvania have found that the community-built encyclopaedia measures up on both accuracy and depth when compared to a peer-reviewed information service for cancer patients – it’s just not very well written.

Doctors often caution their patients against seeking medical advice online, fearing that the information they find could be inaccurate. After all, anybody can create a website that claims to provide expert knowledge, but how can you be sure they’re telling the truth?

You’d think the problem would be even worse on a website that anyone can edit, but Wikipedia turns out to be just as accurate as the National Cancer Institute’s Physician Data Query (PDQ), which was specifically created to cater to patients needs.

Yaacov Lawrence, an assistant professor of Radiation Oncology at Thomas Jefferson University, selected the key facts about ten types of cancer from standard textbooks and ask medical students to compare them against Wikipedia and PDQ. They found that less than 2% of the information of both sites was inaccurate, and the depth of coverage was comparable.

The key difference in the texts was revealed by a readability test, similar to those found in Microsoft Word. Analysing the text of both websites showed that while PDQ was suitable for 14-year-olds and up, cancer articles on Wikipedia are at a university student’s level.

“PDQ’s readability is doubtless due to the site’s professional editing, whereas Wikipedia’s lack of readability may reflect its varied origins and haphazard editing,” said Lawrence. “Overall our results are reassuring: on the one hand Wikipedia appears to be extremely accurate, on the other, the resources invested in the creation and upkeep of the PDQ are clearly justified.”

Of course, just like Wikipedia, this research could be subject to change. Perhaps some knowledgeable science communicators will take it upon themselves to whip up the cancer articles into something a little more readable? Go ahead and hit that “Edit” button…

Male crickets that grow up surrounded by the songs of many potential competitors, grow up bigger and stronger than counterparts reared in silence. It seems that the sound of masculine chirps ends up masculinising young crickets within hearing range.

Researchers from The University of California, Riverside, measured the testicular tissue mass of young male crickets that had been played cricket song, and found that they grew up to have nearly 10% more testicular mass than the youths without such auditory cues of competition. A big part of the male crickets’ mating strategy involves a long-range call. The song can be ‘parasitized’ by other males, who lurk nearby, taking credit for the masculine calls to impress arriving females. But, the males that grew up surrounded by the songs of other males were less likely to use such underhand tactics. Instead they were generally bigger, noisier and in overall better shape.

It seems mating matters to crickets, in fact so fixated are decorated crickets that they will sacrifice their health to impress the females. As part of the mating process, males offer their mates an adorably named ‘nuptial food gift’, a gummy blobby concoction that they synthesize and transfer to the females along with sperm. Scientists from Illinois State University managed to coerce some decorated crickets into producing larger food packages, which they did, despite it lowering their immune systems.

After all that effort, when the deed has been done, mating mission accomplished, there’s still no guarantee that the sperm that entered the female cricket will be the sperm that fertilises her eggs. Of course some of it will be, but with the promiscuity of female crickets, and the aggressive mating tactics of males, multiple matings with the same female are common. So, who becomes the daddy?

Researchers from Exeter university found that even after mating with up to ten males, promiscuous female field crickets can control the amount of sperm that they store from each mate, regardless of the order they mated in. Although crickets don’t avoid mating with relatives, they do reduce the chances of producing unfit inbred offspring, by using their abdominal muscles to keep hold of more of the sperm from unrelated males. Scientists from Australia and Switerland went further and found that a male’s chances of fathering “increases with its attractiveness and decreases with the size of the female”.

In the harsh world of insect reproduction, once the eggs have been laid, the little ones are on their own. Although the mothers don’t stick around, researchers at the University of South Carolina Upstate, have found that they can leave hidden maternal messages in their unborn babies, to prepare them for the harsh realities of existence. Storm and Lima (researchers, with names like comic superheros), placed pregnant crickets in enclosures with predatory wolf spiders whose fangs were tipped with wax. This meant the spiders could stalk the crickets, make them extremely frightened, but not actually kill them.

The offspring of mothers born to the spider-stalked mothers were faster to react to the danger of predators, than the control offspring from mothers kept more cushy circumstances. These offspring of ‘stalked’ mothers ran for cover more quickly and stayed in hiding for more than twice as long. They would also freeze when coming across signs of their predators, signs such as spider silk or spider faeces. Having this fear, unsurprisingly meant that they ended up with higher survival rates.

Who needs facts?

We all know that science can be complicated and confusing, but don’t let that get you down – Fake Science is here to straighten everything out. Did you know that the periodic table is actually based on Scrabble, or that wind power uses giant fans to make wind? Science has never been so simple.

Want to lose weight? Keep it off your plate

Simply leaving serving dishes on the kitchen counter rather than bringing them to the dining table reduces the amount of food you eat, say researchers at Cornell University. They found that this simple dieting strategy reduces the temptation of second helpings, cutting the number of calories people consumed by 20%.

Brian Wansink, director of the Cornell Food and Brand Lab, said that the same idea can be used to promote healthier foods over sugary snacks – keeping fruit on display makes you more likely to eat it instead of reaching for a piece of cake in the fridge.

Animal privacy? Not in my backyard

Wildlife documentaries infringe an animal’s right to privacy, says Brett Mills, a lecturer in film studies at the University of East Anglia:

“We have an assumption that humans have some right to privacy, so why do we not assume that for other species, particularly when they are engaging in behaviour that suggests they don’t want to be seen?”

I’m a staunch defender of civil liberties, but even I think extending the right to privacy to animals is going a bit too far. Of course, great care should be taken to avoid distributing their natural habits or causing them distress, but I really don’t think animals mind us watching them doing what they do.

Green tax would hurt the poorest

A proposed tax on carbon footprints would hit the poorest households hardest, according to study from the University of Leeds. The carbon tax would cost low earners 6% of their annual income, while the richest households would only pay around 2%.

The difference is the result of poorer households spending more on costs such as heating and electricity – 40% of their income, compared to just 8% for high earners.

Print your own skin

Researchers funded by the US military are working on a way of printing new human skin as a treatment for burn victims. What’s more, they’ve using a regular inkjet printer and cartridges filled with human skill cells:

Grow your own font

Typographer Craig Ward has developed a typeface with a difference – each letter was grown from live cells and moulded into the correct shape.

Forensic experts are unable to accurately determine the age of bruises on the bodies of crime victims, say researchers at Queen Mary, University of London. A study published in the Journal of Forensic and Legal Medicine, suggests that sentencing of criminal cases involving bruising, such as child abuse or assault, could be based on flawed conclusions.

The researchers evaluated the bruise-judging abilities of 15 forensic experts with the aid of 11 willing volunteers and a suction pump. Each subject used the pump to inflict bruises on themselves, which the researchers photographed daily until they had faded completely. The photos were digitally altered to remove any hints that might aid the experts in estimating their age, such as marks from the suction pump, then randomly presented for them to judge. They were also asked to place a series of photos in chronological order, identifying how the bruise faded over time.

While we’re used to seeing experts on TV pin down the time of a crime to the nearest minute, the reality is somewhat different. The median difference between the expert’s assessment and the true age of a bruise was 26 hours, but some were even further out, with one expert getting it wrong by 454 hours or nearly 19 days.

Fresher bruises were easier to identify, with a 52% success rate for injuries under 12 hours old, but accuracy fell as the bruises faded. There was a slight increase in accuracy for injuries over 6 days old, but this could be due to chance as there were only a few bruises that lasted this long.

The experts fared better at the second task, placing the bruise images in chronological order without too many mistakes. The results seemed to depend on the nature of each bruise rather than the skill of the experts, because some bruises showed clearer changes in size and colouration than others.

Incorrectly judging the age of a bruise could have significant effects on a criminal trial, either by allowing perpetrators to get away with their crime or placing the blame on an innocent suspect. The study authors conclude that forensic experts’ estimates are unreliable at best, which calls into question whether they should be used in court at all.

Pilling, M., Vanezis, P., Perrett, D., & Johnston, A. (2010). Visual assessment of the timing of bruising by forensic experts Journal of Forensic and Legal Medicine, 17 (3), 143-149 DOI: 10.1016/j.jflm.2009.10.002

Not really, I’ve just been ill, but that sounds less dramatic. On with the roundup!

Emailers or e-liars?

It’s more tempting to lie when you’re sending a message via email compared with using pen and paper, say psychologists at DePaul University in Chicago. They asked 48 students to split an imaginary pot of $89 by choosing the amount in the pot they would tell their partner and how much they were willing to share. Some conveyed their choice using email, while the rest wrote it down.

Nearly all of the emailers (92%) lied about the amount of money available, versus just 62% of letter writers. Participants reported they felt more justified in this deception, and also kept more of the money for themselves. Next time you’re doing a financial deal, be sure to get it in writing of the non-digital variety…

Don’t drink and drag

Everyone knows that smoking and drinking is bad for your health, but it seems that doing both at once could be even worse. Drinking moderate amounts of alcohol, such as two small glass of wine per day, has previously been linked to a reduced risk of stroke, but a 12-year study has found that smoking may counteract this benefit.

The study followed the drinking and smoking habits of 22,524 people in the UK. Moderate drinkers who didn’t smoke were 37% less likely to have a strike than non-drinkers, but the same wasn’t true of smokers.

Less is more when it comes to dating

Speed dating is increasingly popular these days, but it may not be the best way to find “the one”. When meeting a large number of potential partners, the brain may become overwhelmed by choice and end up resorting to surface values, instead of what’s inside.

A study published in Psychological Science found that people at speed dating events with 24 or more dates were more likely to pick a partner based on their weight or height, while those at smaller events took a deeper look, taking in into account attributes such as education and employment.

Guest blog time! My fellow Imperial alumni Mia Kukathasan tells us how mice show some people may have depressive tendencies in our genes. Look out for more from Mia soon…

Scientists have genetically engineered mice with a predisposition for depression. The study aims to find out why, when faced with stressful situations, some people’s are genetically more prone to fall to depression. The mice were altered to carry a genetic change that affects serotonin transport in the brain, mimicking a change that occurs in people with the condition.

“There is a clear relationship between a short form of the serotonin transporter and a very high vulnerability to develop clinical depression when people are exposed to increasing levels of stressful life events.” says Dr. Allesandro Bartolomucci of Parma university, Italy.

Brain imaging of people with depression shows that they have greater activity in some brain areas, but the link with genetics is not as well understood. Chemical changes could be seen in these ‘knock’out’ mice in areas of the brain that regulate memory formation, emotional responses to stimuli and social interactions, such as meeting new mice. They showed physical signs of stress with changes in body temperature, body weight gain, higher levels of the ’stress’ hormone corticosterone and lower levels of the ‘feel good’ hormone serotonin.

Depression is the number one cause of ‘disability’ worldwide, according to the World Health Organisation with 120 million people affected globally. The increased risk of hormone imbalances, heart disease, digestive problems and reduced immune response faced by depressed people makes it a formidable foe for the health services. The work from this study will help to find out how this genetic change in people affects serotonin turnover in the brain. The results published in the journal Disease Models and Mechanisms suggest that the genetic mutation causes an exaggerated response to stress.

Pac-Man in the moon

Mimas is fast shaping up to be the nerdiest object in the solar system. The tiny moon of Saturn has already been compared to the Death Star from Star Wars, but the Cassini probe has revealed another geek-culture icon – Pac-Man.

Nom nom nom

The appearance of the classic video game character during a thermal scan of Mimas has baffled scientists. It could be due to differences in texture on the moon’s icey surface. Old, densely packed ice conducts heat away from the surface, while recently fallen snow acts as an insulator, trapping heat to create the distinctive Pac-Man shape.

Just A Review: Just A Theory

Physics World has published a rather nice review of Just A Theory. You’ll have to register on their site to see it in full, but here’s an excerpt:

Just A Theory offers a moderately UK-centric perspective on science news for interested members of the public and busy professional researchers alike. You will not find too many detailed, hard-science articles here, but sometimes that is not the point. As a student or professional physicist, it is easy to develop tunnel vision as you dig ever deeper into a relatively narrow research topic, but keeping the “bigger picture” in sight can be a time-consuming process in an ever-more-crowded media world.