The Pain of the Death Penalty

This story describes how accused murderer Jared Loughner seems to have conducted at least some research on the Internet (through Google) about the physical pain of lethal injection.  What, if anything, can we draw from this fact?  Can this be counted as an example of the death penalty not being an effective deterrent? 

It depends, at least in part on what Loughner found and how it influenced him.  If he found information that convinced him that the pain of lethal injection was mild by comparison with the expected benefit ("pleasure") of the killings, then Loughner as rational calculator would not have been deterred, and one could say that the death penalty was not an effective deterrent.  But one could just as easily say that the death penalty might have deterred him if he had instead found information that the method of its administration was extremely painful, or at least if it outweighed the expected benefit.

This is a fairly crude argument founded on premises of deterrence, and I should make clear that I wouldn't endorse the death penalty for this reason, let alone an extremely painful death penalty for general deterrence purposes. 

But it did get me wondering about the relationship of general deterrence to actual facts.  If Loughner Googled "lethal injection," and if he found some source that said that lethal injection was not very painful, then perhaps one could speculate that he was not deterred by the threatened painfulness of death.  But what if the source(s) that he consulted was/were wrong?  After all, the Internet is chock-full to the gills of completely erroneous information.  That means that his assessments might very well be flat out mistaken.  In fact, the same might be true for any method of administration.  And perhaps that means that what matters for general deterrence arguments is not so much rational calculations as control of the sources through which people get their information.  These may very well be irrational calculations.  I suppose one could say the same for any general deterrence claim, but the amount of pain experienced by people who are killed by various methods seems to me to be a particularly tricky thing to get hard data on (maybe I am wrong about this).

If we wanted to maximize the general deterrent effect of the death penalty, and we were focused on the question of pain as a deterrent (i.e., we set aside the question of the certainty of the DP's imposition [ADDENDUM: just thinking about it a little more, it seems to me that certainty of imposition would be much more susceptible of uniform factual accuracy than degree of pain experienced]), we wouldn't care so much about the quantum of pain actually experienced.  What we'd want is to make the death penalty appear as painful as possible, whatever the actual truth of the painfulness of our favored method of administration.  And to do that, we would need to control the channels by which ordinary people get their information -- more and more, the Internet.  Otherwise, we couldn't predict very accurately what they would choose.

Again, let me emphasize that I'm not making any general claims about the moral status of the death penalty here.  For these purposes, I'm only trying to think about how a deterrence theorist might think about the social utility of the pain of the death penalty.   

ADDENDUM #2: As an experiment, I Googled "pain lethal injection."  The first two hits lead in exactly opposite directions.  The first was this story from "The New Scientist" which reports on findings that lethal injection is "far from painless."  The second contains language suggesting that those who receive lethal injections feel no physical pain other than from the insertion of catheters.