In a preliminary 2 x 2 x 3 (participant gender x accused person’s gender x DNA condition) ANOVA, there was no main effect of participant gender and no interactions involving this variable, Fs < 1. 00. Therefore, participant gender was not used in a 2 x 3 (gender of accused person x DNA condition) ANOVA. As hypothesized, there was a main effect of DNA condition, F (2, 234) = 11. 91, p < . 001. Participants who received the scenario which only mentioned the presence of DNA evidence were most certain of the accused person’s guilt (M = 4. 88, SD = . 32).
Those who received no information about DNA were more certain of the person’s guilt (M = 4. 01, SD = . 59) than those who were informed it was possible to plant DNA evidence (M = 2. 43, SD = . 86). In a Neuman-Keuls’ test of the three DNA condition comparisons, all ps < . 001. Also as hypothesized, there was a main effect of the accused person’s gender, F (1, 234) = 32. 53, p < . 001, with greater certainty of guilt when the accused person was a father (M = 4. 02, SD = . 57) than a mother (M = 3. 52, SD = . 93).
However, there was a two-way interaction of the accused person’s gender with DNA condition, F (2, 234) = 3. 74, p < . 05. In Tukey tests comparing the gender difference in each of the 3 DNA conditions, there was greater certainty that a father was guilty than that a mother was guilty when participants received no information about DNA and when they received information that it was possible to plant DNA evidence, ps < . 01. However, the means for mothers and fathers who were accused of sexual abuse were virtually identical, i. e. , the rating scale difference was .02 (Ms = 4. 89 and 4. 87 for mothers and fathers respectively), ns.
As noted above, participants also indicated the extent to which they agreed with three statements, using a 5-point scale, where low numbers corresponded with agreement (e. g. , 1 = strongly agree). Responses were used to assess participants’ knowledge of basic memory processes that are important in evaluating testimony.The mean (and SD) for agreeing that young children did not have enough knowledge about sex to remember a sexual experience that never occurred was 2. 2 (.49), lower than the scale average of 3, which corresponded with being uncertain, non-directional one-sample t (234) = 20. 64, p < . 001. Responses indicated that participants generally were incorrect in agreeing with the statement. The mean (and SD) for the statement that memories of childhood experiences usually do not change over time was 3. 4 (1. 01), t < 1. 00, indicating uncertainty about an incorrect statement.
The mean (and SD) for the statement that people may honestly believe they remember an experience that never occurred was 4.2 (. 51), t (234) = 21. 30, p < . 001, indicating participants were poorly informed in disagreeing with an accurate statement. Discussion The results reported above were compatible with the theory that jurors would be convinced of an accused person’s guilt if told of DNA evidence that could be interpreted as “proof” of guilt. The presence of DNA evidence about a person other than the accused has correctly been interpreted as evidence for freeing prisoners who had been convicted at a time when DNA evidence was not possible to obtain.
However, most people now know about DNA testing and the many remnants of a person’s presence that could be tested. Thus it is possible for a guilty person to plant evidence that could be used against another person or for someone to plant evidence that could be used against an innocent person. In the scenario used in the current study, the accused person may have been guilty or innocent. The results suggest that with no information about how it is possible to plant DNA evidence, people may conclude an innocent person is guilty.
However, the information provided in the study about planting DNA evidence could have resulted in concluding a guilty person was innocent. Thus, it is important for researchers to investigate appropriate ways to inform people that it is possible to plant DNA evidence without creating the assumption of innocence as apparently resulted in the current study. There are at least two ways to interpret the find in the study that the accused person’s gender interacted with DNA condition.
First, the effect of receiving DNA evidence without any explanatory information might have resulted in many people feeling certain that the accused person was guilty – and, obviously, one cannot be more certain than certain. However, this interpretation is unwarranted because in the scale used in the current research, there were only two numbers indicating certainty (4 = almost certain and 5 = certain) and the means for women and men who were accused were close to 5. It probably would have been better to use a percentage scale, where respondents would have been able to choose from more numbers expressing degrees of certainty (e. g. , 85%, 92%, 99%, 100%).
Responses to the statements assessing knowledge of basic memory processes indicated that participants, i. e. , potential jurors, were not well-informed, justifying the use of expert witnesses to testify about research findings in studies of memory.
References Bartlett, F. C. (1932). Remembering: A study in experimental and social psychology. London: Cambridge University Press. Basow, S. A. (1986). Gender stereotypes: Tradition and alternatives. New York: Thomas, Brooks/Cole.