Fri 14 Nov 2014
Fri 14 Nov 2014
Mon 20 Oct 2014
Yes dear Cowpokes, Dr Larry Marshall, a man whose scientific credentials barely cast little more than a dim glow from within the deep shadow of his business escapades, and whose tumbling grammatical trainwreck of a biography uses expressions like ‘leverage’ and ‘serial entrepreneur’, wants to create water dowsing machines.
Larry says he would…
…like to see the development of technology that would make it easier for farmers to dowse or divine for water on their properties.
“I’ve seen people do this with close to 80 per cent accuracy and I’ve no idea how they do it,” he said. “When I see that as a scientist, it makes me question, ‘is there instrumentality that we could create that would enable a machine to find that water?’
You know what, Larry? When you see that – as a scientist – you should actually ask yourself why no real scientists believe, for even a nano-second, that dowsing works.
You have no idea how they do it? My suggestion is that you look up the ideomotor effect and watch this video. Several times, if you don’t get it on the first run through.
Thu 16 Oct 2014
Image: Bill Brooks Creative Commons; Some Rights Reserved
Or: You Keep Using That Word. I Do Not Think It Means What You Think It Means
Homeopathy is crap. Serious, unmitigated, archaic, superstitious hogwash-laden crap. There is no defensible argument for why it might have the magical qualities with which it is imbued by some. On that, Faithful Acowlytes, I think you and I are agreed. I’ve noticed in recent times, however, a growing tendency from the dozen or so remaining supporters of homeopathy, to wheel out the justification that its validity might lie in the Placebo Effect.(i) The Placebo Effect is also cited by supporters of various other dubious unscientific medical practices (yes, I’m looking at you Mr Acupuncture) as a possible legitimate modus explainii.(ii)
The problem is that the concept of the Placebo Effect has become eroded over the decades into a magical-thinking term of its own, specifically, a notion that a placebo invokes some kind of Mysterious Ability Unknown to Science for the human body to heal itself, based on a sort of ‘mind-over-matter’ mechanism that remains to this day entirely unexplained. As someone who understands what the Placebo Effect actually is, this really annoys me. And when I’m annoyed, I dust off the soapbox.
Today on TCA, we’re going to look at the exact meaning and intention of running placebo mitigated trials in medicine, and why the explanation for the Placebo Effect is most likely dull and unexciting. Prepare to have your illusions shattered.
To help illustrate things, I’m going to give you a very basic example of how a clinical trial involving placebos might work – it’s not the definitive way of conducting a placebo-based experiment, but for the sake of simplicity it covers all the issues that we need to examine.
Imagine that you have invented a new drug for the relief of nausea. All your theory says that this drug is the bees knees, but to meet the many requirements of getting a modern pharmaceutical legally to market, you must demonstrate this to the satisfaction of the various bodies that regulate this kind of thing (and, as unbelievable as a lot of people seem to find it, this is actually quite tough). What you are obliged to do is to set up a blind – or double-blind – trial (we’ve talked about blind trials before on the Cow, but click on that link it you want a refresher) which takes into consideration numerous factors that might influence your potential outcome. Understand: you do this in order to rule out as much external influence as possible that might offer alternative explanations for results of your experiment. In other words, you’re trying to demonstrate that your drug, and your drug alone, is responsible for any observed lessening of nausea for your patients.
The problem is this: in many areas of medicine, the results of interventions are not totally clear cut. Experience of nausea, for example, is partially subjective, and what you’re trying to do with your experiment is to get an objective overview of how your drug influences a patient’s assessment of nausea. It is very important, therefore, to iron out any irregularities that might be caused by, for example, a subject’s expectation of what a treatment might do.
If you have a hundred patients, and you give fifty of those patients a pill and fifty nothing at all, then half your study knows with certainty that they didn’t get the ‘anti-nausea pill’. This might influence what they report in regard to their nausea. Maybe it won’t, but you have to consider the possibility that it will, and set about ruling it out. The obvious thing to do, then, is to split your group into three parts instead of two, give one third the new drug, one third a capsule identical to the one containing the anti-nausea drug – but with no active ingredient – and one third nothing at all. If the drug has any merit, then what you would expect to see here is positive results from the drug, and then equally neutral results from both the the empty pill (the placebo) and those who got nothing at all.
Are you with me? Does this sound reasonable?
Well that’s exactly what scientists do in blind test trials with placebo controls. Only… pretty much every time this kind of experiment is run, the results inevitably look funny. If the drug is efficacious, the patients who get an active ingredient post a positive assessment of their nausea relief, as you would indeed hope. The patients who got zip (representing what is called the baseline) report a neutral assessment of change in nausea levels. The placebo arm in this kind of experiment, however, almost invariably returns a result of marginal improvement. Better than baseline, but not as good as the active drug. In other words, it seems that the patients who think they might be getting some kind of medicine appear to get an actual physiological benefit from simply popping a pill.
How utterly weird is that? Imagine the puzzlement among experimenters the first few times these kinds of results came back!
Now we get to the real problem of the misunderstanding of the Placebo Effect. Over the years, this result, which is a very real result and is seen almost without fail in a great number of clinical trials, has been taken to mean that the ‘idea’ of taking a pill (or indulging in some other kind of intervention) can have an actual physiological effect on a patient. To put it another way, it appears that if someone thinks they’re being treated, then somehow they seem to physically benefit from being under that illusion.
Only, that’s not exactly what the Placebo Effect is showing us.
In science, a placebo trial has a specific and clearly defined purpose: to account for all other variables from the experiment that can’t be explained by the agonist of the experiment itself. This would indeed include any strange psychological influence on physiology should such a thing exist,(iii) but it need not necessarily be constrained to only this. What most people fail to understand is that the Placebo Effect may also include numerous other factors. Some of these are: patient reporting bias; risk justification; confirmation bias and even just the kind of bias that might be inherent in being involved in a clinical trial in the first place. What do I mean by some of these? Well, let’s say you’re a patient in a study such as the one I suggested above. You are given a pill twice a day for the period of two weeks. You’ve given up some of your time to be on this trial (recording and reporting results and so forth) and you like the doctor who is treating you. This might very well influence what kind of modification to your results you record – only a little bit, perhaps, but ‘only a little bit’ is the scale of the typical observed Placebo Effect.(iv) Note that you might not necessarily be really feeling any difference in your nausea levels, but you are being ‘kinder’ on reporting them to the nice doctor (you would not even be aware of this – you are being given a pill and, in your mind, hey, it might be the anti-nausea drug… maybe you should be feeling a little better…) In addition to this kind of scenario, people involved in clinical trials behave differently to people in their actual usual lives. There is a tendency, for example, for them to be more aware of their day to day health and to take a little more care than usual with it. This of course can produce real physiological results that can easily colour their experience in the trial.
These things are very difficult to iron out of an experiment, and that’s EXACTLY what the Placebo Effect is all about – it is a generic container for the strange and uncatchable inconsistencies that occur when attempting to run an experiment where there are a lot of variables.
To boil all this down, it may well be that the Placebo Effect in any given clinical trial – and perhaps in all clinical trials – is down to nothing more than erroneous reporting; not any kind of physiological outcome at all, but just a noise phenomenon in the experiment that produces illusory effects simply because it is an experiment and not reality. In the actual real world, the thing we think of as the Placebo Effect may not even exist, and it’s impossible to verify such a speculation since trying to do so would necessitate the undertaking of an experiment and thus risk producing a horrible spiral of nausea-inducing recursion.
So the next time you hear someone justifying some kind of pseudoscientific ‘alternative’ remedy or other by invoking the Placebo Effect, I suggest you do the following: look them squarely in the eye and say, with a lisp… “Inconceivable!”
Sun 15 Dec 2013
No-one else is running with that headline, so I’m just doing my duty…
Yes, it’s actually science.
Sun 4 Aug 2013
Over the past four years or so, I’ve been creating a major new work, which I’m pleased to say is now completely finished – aside from one further process: a production run to render it to Bluray so I can make it available to the world. To this end, I’m holding a crowdfunding campaign over at Pozible. There are some really nice rewards involved (most of them including a copy of the final Bluray itself). If this is something you think you’d like, chip in and help me make it a physical object. Also feel free to copy the link on to friends & other interested parties. All help will be greatly appreciated!
Sat 23 Feb 2013
So at last, my mysterious project is complete.
You saw Laura a couple of days ago as she arrived, straight out of the box. She was not quite as perfect as I would have liked, so the first step involved some surgery…
As did the second step. ‘Trust me Laura,’ I said ‘I’m a doctor’. Well, I’m a Reverend, and that’s as good as, right? I mean, with
God the Cow on my side, how can I do wrong? A little release of intracranial pressure…
Ah, that’s better. And now for the pièce de résistance… And Binauralaura (Laura to her friends) is ready to begin to listen…
Binauralaura is my new binaural recording rig. Here begins the edumacation part of this post, so those who came for the titillation can now go watch Fox news and eat donuts.
To start, you should know that when you hear a stereo recording of sound or music – pretty much any recording – it is presented to your ear in a very different way to the way in which you actually hear in reality. There are many reasons for this, but the main one is that most sound recordings, and most music recordings in particular, use a somewhat artificial method to render their stereophonic sonic landscape. In a standard electronically-reproduced stereo domain, the stereo image is created from two point sources – your two hifi speakers, or two headphone speakers – each of which is fed by a discrete channel of recorded sound. All sound in a stereo field is thus contained in two separate, but interconnected, recordings – one for left and one for right. In simple terms, if a sound is only in the left channel, it will appear to come from your left. If it is only in the right channel, it will appear to come from your right. In almost all modern recordings, when an engineer wishes to make a sound feel like it is originating elsewhere in the stereo image – slightly left of centre, for instance – it is made slightly louder in the left channel than it is in the right. To make it appear to be right in front of you – or ‘centre’ as we say – then the volume is made exactly equal for both the left and the right channels. For over half a century, this result has been achieved by ‘panning’ the sound on a mixing console. A panner is simply a control that varies the amount of signal (or loudness) added to each channel.
In the real world, though, our ears don’t judge the position of a sound in space solely by its loudness. Certainly, loudness is one aspect of the mechanism, but there are numerous other factors in play. The principal one is a component of time. If you hear a dog barking somewhere ahead of you, and slightly to the left, one of your ears will be receiving a slightly greater sound pressure (loudness) than the other. But crucially, that same ear will be hearing the sound very slightly before your other ear does. The human brain can, in fact, differentiate time differences smaller than 10 microseconds between your two ears, and it is that ability which allows us to aurally locate objects in space with an accuracy of about 1 degree.(i)(ii) Up until very recently, this time component could not be easily recreated in a studio mixing environment, and since – like most things – the recording process is a trade-off between the achievement of perfection and economic imperative, the old panning paradigm is still alive and well (and dominant) in modern sound mixing facilities. I would make a rough guess that 99.9% of all music and sound you hear is rendered to stereo with crude analogue panning.
Now, some of you may be ahead of me slightly here, and interject: ‘But Reverend, what about a recording made solely with two microphones? There’s no mixing console involved there (so no artificial panning) and the sound of any object off centre to the microphones must arrive at slightly different times for each? Surely that’s preserved in a recording?’
Well, yes indeed. Two separate microphones (or a coincident stereo pair, to use the lingo) will indeed preserve the delay times inherent in the scene being recorded but they still don’t hear the world like our ears do.
The important thing to understand at this point is that when it comes to human hearing, our eardrums – our ‘microphones’ if you like – are only part of the story. There are several other key players in the process, the most important of which is our brain. Our brain and ears work together to ‘hear’ the world, and the way we hear is a lot more complex and clever than you probably ever stopped to think about.
One thing that every one of us knows (because our brain figures it out pretty much as soon as we are born) is that our ears are separated from one another by a head. Everything we experience in the realm of natural hearing is mitigated by this big noggin right in the middle of things. And our brain calculates our aural experience by taking it into account as it forms our sonic picture of the world. Likewise, we are accustomed to hearing our surroundings via two fleshy reflectors that funnel the sound toward the vibrating membranes that actually detect the sound waves. The complicated contours of our ears – the pinnae – don’t simply look like they do for decoration. The whorls and cavities of the ear surface impose certain kinds of characteristics on the sound that reaches them, and these help us with sound localisation, and, to a certain extent, with the perception of fidelity.
Which brings me all the way back to Binauralaura. Laura’s head contains a pair of high fidelity omnidirectional microphones that sit in her ears just at about the place where the outside part of the human ear canal would start.(iii)
Her silicon pinnae are created from a CT scan of real human ears and these and her head create an aural ‘shadow’ which will match, in a generic way, the listening field of most humans.(iv) This means that a recording made with Binauralaura, will sound about as real as an audio recording can sound.(v)
So if binaural recording is so magnificent, why isn’t it used for everything? Well, there is, of course, a catch. The binaural effect can only properly be discerned by wearing headphones. For the binaural image to remain coherent, the sound for one ear must not interfere with the sound for the other. Additionally, in order to avoid a doubling of the head and pinnae shadow (one gained from the recording, and then a second from the listener’s own head and pinnae), the reproduced sound needs to be played back as close to the listener’s ear canal entrance as possible. The most expedient method to do this is via headphones or earbuds.(vi) Wearing headphones to properly hear binaural sound is, in fact, analogous to the requirement to wear glasses to see 3D images (indeed, binaural sound is often described as ‘3D’ or ‘holophonic’ sound).
I’ve had some opportunities to take Laura out for a bit of a test spin, and so far, the results are pretty nice. Here’s a short clip. Remember – wear headphones or earbuds to listen to it. One thing you will immediately notice is the clarity and and detail of the sound space. If your hearing is fair, you may also detect one of the extraordinary features of binaural sound – something you will not hear in a conventional stereophonic recording – and that is the ability to localise sound height. Have a listen now, and see why I went to all the trouble to build Binauralaura.
Download Laura Listens