by Simon Cohen

Created on: November 26, 2010   Last Updated: November 27, 2010

From a psychology standpoint the death penalty is not justifiable, as the process used to determine guilt, i.e. police interrogation, judgement by a jury of peers, is psychologically unsound. Capital punishment is used in many countries around the world such as China, Ecuador, USA, North Korea etc, but for the purposes of this article we’ll stick with the USA as a focal point. This article will follow a hypothetical criminal case and show how each stage is open to questions of validity.

The most common cases in the US to go to capital punishment are murder cases, so we shall begin there. Person A (PA) is found murdered at their home; the police, after conducting an investigation bring in suspect B (SB) for an interrogation. Since they brought in SB, the police, by definition, must think he is guilty. As the interrogation continues the police, by viewing the body language and responses become more and more convinced of his guilt, but research has shown that police are no better at assessing guilt than normal people (Eckman et al. 1999). Still, this predisposition to guilt will be apparent in the interrogative technique, which will be more aggressive and use more questioning techniques to try to elicit a confession (Kaisin et al 2003). This harsher interrogative technique and more aggressive is more likely to create a coerced compliant confession (SB goes along with what the police want, regardless of whether he committed the crime) or a coerced internalised confession (SB comes to believe own guilt, even though they might not have done anything) (Kaisin and Kiechal, 1996). On the face of it we have a suspect who has confessed to a murder, under the surface we see that SB may or may not have committed this murder.

Moving on. SB has been informed that due to the nature of the crime he is eligible for the death penalty, and if judged by a jury of his peers to be guilt, he we be killed. Herein lies another quandary, do jury’s understand their mission. Let’s have a look at the research. In order to be found eligible for capital punishment the defendant must have committed at least 1 of 7 aggravating factors. If eligibility is reached, then the jury deliberates and assesses any mitigating factors that might be used in order to use a lesser sentence. Diamond 1993, in reviewing the death penalty found that the language used to instruct jurors on the death penalty was almost incomprehensible to them. The use of unfamiliar phrases (i.e. ‘sufficient to preclude’), complex sentences and ambiguous words (i.e. aggravating) meant that the jury didn’t know what they were supposed to be including in their deliberation. The findings were replicated in Kalvin and Ziesel’s 1996 study and Sandy’s in 1991 found that jurors didn’t know if to include a mitigating factor you needed unanimity that it was mitigating. They also didn’t know if 2 weak mitigating factors could be combined to form a strong one and had confusion over the alternatives to death i.e. life/life without parole.

I am not saying that every death penalty case ever completed was wrong; I am just saying that the possibility remains in every case for human error. While for the most part it’s not a big deal because decisions can be reversed, capital punishment is irreversible and if the possibility remains open that the wrong person has been sentenced, then surely there can be no justification for the death penalty.

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