Factors affecting testimony about mitigating circumstances and the fixing of punishment

Although trial attorneys typically choose to have defendants testify on their own behalf, there are data from studies using simulated juries which suggest that the presentation of favorable testimony by defendants might be harmful. Data from these studies are suspect, however, because subjects' verdicts had no realworld consequences. In the present study the real-world consequentiality of subjects' verdicts (some vs. none), the presence of mitigating testimony (some vs. none), the source of the mitigating testimony (defendant vs. third party), and the credibility of mitigating testimony (high vs. low) were all manipulated in order to test their effects on the severity of penalities subjects assigned. The results showed that among subjects whose decisions were of no consequence, none of the other manipulated variables produced any reliable differences. On the other hand, among those who thought their decisions were of real consequence, less severe penalties were given when mitigating testimony was presented as opposed to when it was not, and more interestingly, this was true regardless of the testimony's source. The results are seen as underlining the importance of inducing a sense of consequence in simulated jury studies.