A Case Against Lie-Detection

This post will, in all likelihood, be very brief and to the point. It isn't so much that I've grown weary of my often overly-verbose descriptions of the simplest phenomena. Rather, this topic is so self-explanatory and the conclusions so self-evident that (I would hope) no further discussion will be warranted.

As you may have easily noticed, there is a rather cliche' image above of an individual hooked up to a polygraph machine. I will spend the next x-amount of sentences decrying the use of these contraptions. Let's get this show on the road:

1) Allow me to first direct your attention toward one of the components seen in the picture with which I am quite familiar: the "Galvanometers." These are electrodes situated on the undersides of the fingers, and measure Galvanic Skin Response (GSR), otherwise known as Skin Conductance Response (SCR). I'll use the latter term. Here's the thing about SCR: if you tell a blatant lie, you're aware that you're lying, and realize that the truth could get you in trouble, you will probably show an observable response. Know what else could cause such a response? Being on trial for murder and knowing that your answer to each question and the readings accompanying them may determine whether you're killed or acquitted. The truth of the matter is that there are many, many things that can produce what appears to be a skin conductance response, including but not limited to deep breaths and thinking about the person in front of you naked. These are difficult enough to tease out when in response to a discrete event in a tightly controlled experiment.

2) Next, I'll simply lump blood pressure, respiration (pneumography), and heart-rate into the same category since my criticisms can by and large be levied in conjunction. Quite like SCR, these measures are, without proper context, rather nonspecific. These, however, suffer even more from such ambiguity. There's always a difficulty in making meaningful comparisons within this sort of transient activity without establishing a proper baseline, which I would be willing to bet many polygraph operators don't bother to do. What you're left with is an array of autonomic responses that, again, are probably highly influenced by the fact that these people have been accused of something like murder, and may potentially be put on death row. To ask them to stay calm for good readings would be like asking a hungry polar bear not to eat you so you can see who wins the World Cup. When faced with a moment or time frame that may determine life or death, you effectively have no baseline, and your readings are inherently biased. Particularly because the responses in question (including SCR) are tightly coupled with nonspecific stress. An additional concern in using this method to investigate homicides is that many sociopaths have been shown to have weaker or relatively nonexistent autonomic responses. What does this mean? Well, in a lot of cases, it means that you may only be capable of catching murder suspects lying who didn't actually commit the murder.

3) Here's the main event. Ready for it? Here it is. Ever heard of the "black box" problem? If so, you've probably already got the idea. If not, allow me to briefly explain. Most polygraph tests simultaneously record three or four different measures within the same physical object. Not three or four distinct pieces of hardware with three or four distinct methods of amplifying and cleaning up the signal: the same piece of hardware. These three or four signals go into one machine that assigns parameters to each measurement, and spits them out. You may ask yourself why this is a problem if each parameter is assigned a distinct waveform area on the paper/computer/etc...well, here's the problem. The "black box" concept refers to the idea that data are being thrown into a program or machine that manipulates the data in set ways and spits it back out in a way that is defined as more easy to interpret or compare. However, without adequate knowledge of what's going on inside the program or machine (the "black box"), you're really not aware of where the numbers or waveforms are coming from. That is, if you don't know how the input becomes the output, how can you know that the transformation was accurate? The machine could easily malfunction, and since all of the readings may be affected, you would probably never know. This problem is only worsened when all of the readings are combined into a single waveform, which is a shit idea for the aforementioned reason, and furthermore because something like SCR and blood pressure are only loosely related and totally incompatable within the same frame of measurement. This may be somewhat less problematic if the operators/analysts of polygraph equpment had an extensive theoretical and technical knowledge of the measurements and algorithms involved, but I would be willing to bet that this very often isn't the case.

Thanks for reading.

Now, where were we...

I've enjoyed an extended hiatus from blogging for quite some time now because I've had better things to do with my time.

Alright, alright...that was only a joke.

Kind of.

But really, the entire mileu of blogging has taken on a sort of negative connotation with which I happen to agree, for better or for worse. It's one of the many embodiments of what manages to be at the same time both endlessly exasperating and simply tragic about my generation: we expect that our particular views or opinions are somehow special, and that everyone in the civilized world is entitled (nay, privileged!) to read them. To "blog" is to willingly participate in this self-indulgent spiral of cultural or intellectual musings that are, at the end of the day, masturbatory. Very few of us are paid or reimbursed in any way for this time spent, and very few of us are ever bettered for having read any particular blog entry. So why do it? Again, the answer is simple. Masturbation - of the ego, that is. Everyone loves a little nudge in the direction of "I'm important," and if they claim otherwise, they're more than likely lying to you, themselves, or both.

Perhaps this raises the question of why I'm writing this right now, and rightfully so. If you're expecting an Atticus Finch-esque exculpation, I'm sorry to disappoint you - I'm a child of the "me" generation, probably like yourself, and I'll have mine.


With that said, this is what I've been up to lately:
School and work, which are no longer separate entities. I am plunging headlong into the world of professional research, and for some sick reason, I couldn't be happier. I suppose I'm on my way to becoming a neuroscientist, and with any luck, I will soon be accepted into a decent graduate program and on my way to earning a PhD. This field excited me as a natural result of my fascination with consciousness and mental events, which is, I'm told, not an uncommon occurrence among students of philosophy. However, I seem to have taken a bit more of a proactive approach: I've all but abandoned philosophy in any professional regard. I have done this for two important reasons: 1) modern "philosophers" seem far more interested in winning intellectual pissing contests than in actually making progress in any field, much less their own, and 2) philosophy itself has been absorbed into its related fields to the extent that one is largely better off in simply studying one of those related fields. For example, modern physics has become theoretical to the extent that it is often indistinguishable from metaphysics (save for ridiculous theories about enormous boats being from another dimension, etc.), and modern neuroscience is coming to merge with epistemology such that studying epistemology alone is now ironically philosophically limiting. Neuroscience is at an extremely important position in the history of our species. We are quite literally on the brink, every single day, of discovering some feature of the brain that gives rise to a particular behavior or cognitive state. These things separately may mean little, though taken together, complex behaviors and cognitive states may be explained. So on, so forth until the level of complexity that we understand approaches that of reality.

Given many a mental wrestle and discussion I have had regarding the mind-brain relationship, it may strike those who know me as odd that I am so fervently interested in the ability of neural activity to produce behaviors. Have I resigned to the notion that the brain is the mind? Well...yes, and no. It is, at this point, quite ignorant (or at the very best, unfounded) to hold that the mind is independent of the brain. On the other hand, it's quite clear to me and to many researchers that there is no such one-to-one relationship to be found. The brain's sheer power as a machine and storage device is such that such a relationship is not physically possible or even conceptually plausible. The mind, then, is not to be found in the brain, but is an emergent property of it, of some sort. This relationship may never be wholly understood. But even so, we're getting close enough to be excited.