Science and the Death Penalty

Philip Yam over at Scientific American has posted an item about the relationship of science with the death penalty debate. Interestingly, he does not include racial statistics among his evidence — i.e. blacks are more likely to be executed for similar crimes than whites. I say interestingly because the racial issue has become one of the touchstone issues in death penalty debate and I believe it is a red herring. There is plenty of evidence that capital punishment is flawed without needing to rely on a incendiary issue like race.

How is science related to the death penalty. Well ...

First, there's DNA evidence. Although it cannot prove guilt beyond all doubt — who can forget O.J. Simpson? — it can definitively prove innocence. The first DNA exoneration occurred in 1989 ... [link inserted by me]

So science can both exonerate and help convict in capital cases.

But why would we need DNA to exonerate? What about other evidence?

Thanks to psychology studies, we know that the human brain can, with rather disturbing ease, create false memories... We know that witness testimony can be unreliable... We know that some personality types are more likely to yield to the pressures to confess...

Philip then goes on to show that the error rate in executions might be as high as 1 in 12 (although he goes on to say that is "undoubtedly too high"), but is almost certainly above 1 in 100, setting a potential error range of 1% to 8%.

How cynical is it to support capital punishment when there is a known error rate in the process? Well if you were Gav over at GavPolitics, you might think

And if the death penalty prevents more murders from occuring through deterrence than the number of innocent ‘murderers’ executed, surely that’s okay?

Putting aside the fact that there is no evidence for a deterrent effect — Gav himself seems to think that death would actually be preferable to life imprisonment — that attitude is pretty soulless, if you ask me.

Comments

[Gavin Ayling]

No-one's ever called me a zombie before!

I cannot imagine the horror of knowing that for the rest of your life you would be interred with people capable of committing murder... Maybe I'm being a coward by saying it?

[Chuck]

Gav, (can I call you Gav?)

I hope you understand the zombie link was just a joke.

Using the word "soulless" was not, however, meant as a joke. I think its very cynical to weigh the number of innocents executed against the deterrent effect of the law. The implication is that it is only important how many innocent people die, and its not important who does the killing -- the state vs a criminal. In my opinion, there is something especially bad about state sanctioned murder (which it would effectively be by executing innocent people). There is a reason why our justice system is designed to give the benefit of the doubt to the accused -- even if that provides less deterence.

I did not mean to imply you were a coward. In a way I sort of agree with you about life sentence vs execution. My point was the following: If a life sentence is worse than the death penalty, how does the death penalty provide any deterence? If death is better than life in prison, that's all the more reason to get rid of the death penalty and replace it with life sentences.