Georgia executed Troy Davis last week and I've been thinking a lot about the death penalty. I've often been a proponent of the death penalty in some cases. Some crimes are so heinous, so horrific, that the death penalty feels like justice. But as a cognitive psychologist, I worry that we create injustice by condoning a system that allows execution. Sometimes we may execute the innocent.
Here's my basic problem: People are horrible eyewitnesses. We misperceive things. Our memories are limited. We create false memories in response to misleading suggestions. We reconstruct our memories. People frequently choose somebody in a police line-up even when the culprit isn't there. We are victims of social pressure from friends, family, and authority figures. We are falsely confident after memory errors. The limitations of eyewitness perception, memory, and cognition are almost innumerable.
How bad is the problem of eyewitness memory? The Innocence Project (click to visit their website) reports that "Eyewitness misidentification is the single greatest cause of wrongful convictions, playing a role in 75% of convictions overturned through DNA testing." As a cognitive psychologist, I have no doubt about the fallibility of human perception and memory. No legal system should take someone's life based solely or primarily on eyewitness identification.
The execution of Troy Davis troubles me as a cognitive psychologist. I have not studied the case extensively, so I make no claim about his actual guilt or innocence. But I know a critical fact. Several of the witnesses who testified against Davis in the original trial have recanted in the years since that trial. Many of these witnesses claimed that they were pressured by the police. Since the case against Davis was largely based on eyewitness testimony, I'm troubled. An innocent man may have been executed.
When an innocent person languishes in jail, we can correct the error. People are regularly exonerated in our legal system. The checks and balances generally work effectively, albeit slowly. But when that innocent person has been executed, we cannot correct the error.
There are a lot of reasons to oppose the death penalty. You could have ethical reasons to avoid killing. You could argue that our system applies the death penalty in a biased fashion. You could be opposed to the expense of death penalty cases.
I am against the death penalty because I know that sometimes the wrong person is convicted. I cannot support the possible execution of the innocent.