It was hypothesized that subjects exposed to old versus new instructions would be significantly more likely to believe that mitigating circumstances must be proven beyond a reasonable doubt, that mitigating circumstances must be found unanimously, and that mitigating circumstances must not be considered in the final decision about whether the defendant receives the death penalty. The study sample included 115 subjects, recruited from jury lists, who viewed one of two, 20-minute videotapes prepared either from instructions given in a specific North Carolina trial several years ago or from more current pattern instructions. After viewing the videotape, subjects responded to a series of eight questions to assess their understanding of legal issues presented in the instructions. Compared to subjects exposed to new pattern instructions, those exposed to instructions from the older trial displayed significantly inferior understanding of legal criteria to be used in deciding the existence of mitigating circumstances and for incorporating mitigating circumstances into the final jury recommendation of life imprisonment or the death penalty. Study results are relevant to appeals beyond the specific appeal prompting the current research, and the methodology is applicable to a range of issues. 25 references and 1 table (Author abstract modified)