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Author info: Correspondence should be sent to: Dr. James Couch, 1 Bromley Circle, Madison, WI 53714; e-mail [email protected]. North American Journal of Psychology, 2002, Vol. 4, No. 1, 143-148.

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Eyewitness Testimony and the Jury Verdict

Jennifer N. Sigler and James V. Couch James Madison University

This study examined the effect of a discredited eyewitness on jurors' verdicts. Participants (N = 192) were asked to assume the role of juror as they read one of three scenarios containing circumstantial evidence, circumstantial evidence plus eyewitness testimony for the prosecution, or circumstantial evidence for the prosecution plus eyewitness testimony along with a discredited eyewitness. Results indicated that jurors who read the scenario containing only circumstantial evidence voted guilty approximately fifty percent of the time. Participants who also read testimony from an eyewitness voted guilty more than not guilty. Jurors in the discredited eyewitness condition voted not guilty more than guilty. Voting more in favor of the defendant may have been jurors’ way of punishing the prosecution for perceived trickery.

At the beginning of a trial, the scale of justice is supposed to be

balanced. As jurors hear evidence presented by the prosecution and defense, this scale is often tilted one way or the other. That is, as the prosecution presents evidence against the defendant, “weight” is added on the balance to tip the scale to the guilty side, and as the defense presents information in favor of the defendant, the scale is tipped toward the not guilty side. The role of the juror is to take the evidence assimilated from both sides of the scale and arrive at a verdict, a process similar to that described in Lopes’ meter model (1985).

In a study by Loftus (1974), the effect of eyewitness testimony on the scale of justice was examined. Participants were asked to assume they were jurors in a mock trial as they read a scenario about a robbery and double murder. There were three conditions in the experiment. The first group was given a scenario containing only circumstantial evidence. The second group was given a scenario that included an eyewitness for the prosecution as well as the circumstantial evidence given to the first group. The final group read a scenario that included the elements from group two, but also included testimony that discredited the prosecution eyewitness. Each participant was asked to render a verdict based on the scenario he/she read.

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Results showed an 18 percent "guilty" rate among the jurors who were presented with circumstantial evidence alone (Loftus, 1974). Seventy-two percent of the participants who heard eyewitness testimony voted "guilty." Perhaps the most astonishing finding comes from the discredited eyewitness condition. Sixty-eight percent of the participants in the group where the eyewitness testimony was discredited still voted for conviction. Jurors persisted in their beliefs that the evidence weighed heavily against the defendant, in spite of discredited eyewitness testimony.

While some studies have confirmed Loftus’ (1974) basic finding (Cavoukian, 1980; Saunders, 1981), other research has reported different results (Hatvany & Strack, 1980; Weinberg & Baron, 1982; Saunders, Vidmar, & Hewitt, 1983; Kennedy & Haygood, 1992). For example, Hatvany and Strack conducted a study that simulated a court trial and found conflicting results. In this study, participants were randomly assigned to one of five groups: a no witness control group, a pro-plaintiff eyewitness group, a pro-defense eyewitness group, a discredited pro- plaintiff eyewitness group, and a discredited pro-defense eyewitness group. In the no-witness control condition, 60% of the jurors voted for a guilty verdict (Hatvany & Strack, 1980). In the two conditions in which testimony from an eyewitness was presented, jurors voted in favor of the side with the eyewitness. When the defense eyewitness was discredited, jurors simply disregarded the testimony and guilty verdicts equaled 50%. In other words, the scale of justice tipped back toward equilibrium. However, when the prosecution eyewitness was discredited, jurors “overcorrected” for this faulty testimony by returning fewer guilty verdicts than jurors in the no-witness control condition.

Hatvany and Strack’s (1980) study contradicted Loftus’ (1974) findings by lending support for the discrediting effect, wherein jurors seem to discount eyewitness testimony that is discredited. Other researchers have manipulated numerous variables in an attempt to explore the effects of a discredited eyewitness on jury verdicts (Kennedy & Haygood, 1992; Saunders, Vidmar, & Hewitt, 1983; Weinberg & Baron, 1982). All of these studies have found support for the discrediting effect.

These subsequent attempts to examine the influence of eyewitness testimony on the outcome of a trial used experimental conditions that are very different from the conditions of Loftus’ original study. The question is whether the results conflicting with Loftus’ (1974) findings are due to variations in procedure, or whether the Loftus results are an anomaly. The present study returns to Loftus’ original experiment and its simpler methodology to examine the effect of a discredited eyewitness upon a juror’s verdict.

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METHOD

Participants

One hundred ninety-two students from a mid-size, southern university participated in the study. Students volunteered to participate as one of several alternatives and activities for course credit. Participants were between 18 and 21 years of age. Procedures

Upon arriving for the study, students were asked to seat themselves, and were read instructions explaining the procedure. Students then signed informed consent forms indicating that they were willing participants in the study and that they understood what their participation entailed. They then received a sheet of paper on which one of three scenarios was written. Participants at a given testing period all read the same scenario. There were between 20 and 25 subjects in each session.

TABLE 1 Frequency of Guilty and Not Guilty Verdicts for the Three Experimental Conditions Verdict Guilty Not Guilty Total

Circumstantial Evidence Count 29 35 64

Percent 45.3 54.7 Circumstantial Evidence + Eyewitness Testimony Count 44 21 65

Percent 67.7 32.3 Circumstantial Evidence + Eyewitness Testimony + Discredited Eyewitness Testimony

Count 20 43 63 Percent 31.8 68.3

The first scenario consisted of circumstantial evidence and served as

the control condition. The second scenario included the circumstantial evidence given in the first scenario as well as a prosecution eyewitness. The third scenario contained both of the elements in the second scenario and also included testimony discrediting the prosecution eyewitness. Jurors were instructed to read the scenario given and then indicate their verdicts by marking not guilty or guilty at the bottom of the sheet. There

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was no discussion between subjects. Each participant worked in- dividually and arrived at his/her own verdict. After all participants had reached a verdict, they were debriefed and thanked for their participation. The three scenarios used in this study are included in the Appendix.

RESULTS

Overall, jurors voted for conviction approximately 49% of the time. Table 1 shows a frequency distribution of juror verdicts for the three conditions. A significant chi-square (2, N = 192) = 16.93, p < .001, indicates that the verdict and the scenario are related. Guilty and not guilty verdicts were approximately equal among participants who read the scenario containing only circumstantial evidence. Jurors who, in addition to being given circumstantial evidence, were also given eyewitness testimony voted "guilty" more often (68%) than not. However, in the third condition, when the eyewitness was discredited, jurors rendered more "not guilty" verdicts than "guilty" (32%) verdicts.

DISCUSSION

Results of the present study are consistent with those of Hatvany and Strack (1980) and reported studies that followed (Kennedy & Haygood, 1992; Saunders, Vidmar, & Hewitt, 1983; Weinberg & Baron, 1982), but they are inconsistent with Loftus’ (1974) results. That is, when jurors are presented with eyewitness testimony, their subjective scale of justice tips to the guilty side. When this eyewitness testimony is discredited, however, the scale of justice does not merely return to equilibrium, but goes beyond that point, tipping more toward the "not guilty" side.

Perhaps jurors felt as though the prosecution was tricking them. Voting more in favor of the defense might have been their way of punishing the opposing side for introducing a “bad” witness. Future research might explore what goes on in the minds of jurors when this “over-correction,” as Hatvany and Strack (1980) termed it, is happening. One way of assessing this phenomenon might be to ask jurors to elaborate on how they arrived at a verdict. That way, researchers could learn more about each juror’s subjective scale of justice, and how and why both sides of the balance tip back and forth during a trial.

REFERENCES

Cavoukian, A. (1980). The influence of eyewitness identification evidence. Unpublished doctoral dissertation, University of Toronto.

Hatvany, N. & Strack, F. (1980). The impact of a discredited key witness. Journal of Applied Social Psychology, 10, 490-509.

Kennedy, T. D. & Haygood, R. C. (1992). The discrediting effect in eyewitness testimony. Journal of Applied Social Psychology, 22, 70-82.

Loftus, E. F. (1974). The incredible eyewitness. Psychology Today, 8, 116-119.

Sigler & Couch EYEWITNESS TESTIMONY 147

Lopes, L. L. (1993). Two conceptions of the juror. In R. Hastie (Ed.), Inside the juror (pp. 255-262). New York: Cambridge University Press.

Saunders, D. M. (1981). Discredited eyewitness evidence and jury deliberations. Unpublished master’s thesis, University of Western Ontario.

Saunders, D. M., Vidmar, N., & Hewitt, E. C. (1983). Eyewitness testimony and the discrediting effect. In S. M. A. Lloyd-Bostock and B. R. Clifford (Eds.) Evaluating witness evidence (pp. 57-78). New York: Wiley.

Weinberg, H. I. & Baron, R. S. (1982). The discredible eyewitness. Personality and Social Psychology Bulletin, 8, 60-67.

APPENDIX

Scenario used for Circumstantial Evidence Alone Condition On Friday, November 12, 1997, Mr. Smith, the owner of a small grocery store, was confronted by a man who demanded money from the cash register. Mr. Smith immediately handled $100 to the robber, who took the money and started walking away. Suddenly, and for no apparent reason, the robber turned and fired two shots at Mr. Smith and his five-year-old granddaughter, who was standing behind the counter. Mr. Smith and his granddaughter were hit and died instantly. Two-and-a-half hours later the police arrested a suspect who was charged with robbery and murder. A trial date was set for February 3, 1998. The prosecution presented evidence that indicated the robber was seen running from the store and into an apartment house nearby. The defendant was a resident of this apartment house. After executing a search warrant, the police found $123 in the defendant’s room. Traces of ammonia were found on the defendant’s shoes. Evidence was introduced that ammonia had been used to clean the floor of the store. Paraffin tests, used to determine whether a person has gunpowder particles on his hands from firing a gun, indicated that there was a slight possibility that the defendant had fired a gun during the day. The defendant took the witness stand in his own behalf and testified that he did not commit the crime. He testified that the money found in his room represented his savings from a two-month period. He testified that the ammonia tracing could have been obtained at a different place since he worked as a delivery man and made deliveries to a number of grocery stores in the neighborhood. He testified that he had never fired gun in his life. Based upon this evidence and assuming that guilt must be proven “beyond a reasonable doubt” would you find the defendant….

Scenario Used for Circumstantial Evidence + Eyewitness Testimony On Friday, November 12, 1997, Mr. Smith, the owner of a small grocery store, was confronted by a man who demanded money from the cash register. Mr. Smith immediately handled $100 to the robber, who took the money and started walking away. Suddenly, and for no apparent reason, the robber turned and fired two shots at Mr. Smith and his five-year-old granddaughter, who was standing behind the counter. Mr. Smith and his granddaughter were hit and died instantly. Two-and-a-half hours later the police arrested a suspect who was charged with robbery and murder. A trial date was set for February 3, 1998. The prosecution presented evidence that indicated the robber was seen running from the store and into an apartment house nearby. The defendant was a resident

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of this apartment house. After executing a search warrant, the police found $123 in the defendant’s room. Traces of ammonia were found on the defendant’s shoes. Evidence was introduced that ammonia had been used to clean the floor of the store. Paraffin tests, used to determine whether a person has gunpowder particles on his hands from firing a gun, indicated that there was a slight possibility that the defendant had fired a gun during the day. A store clerk who was in the store during the robbery testified that she saw the defendant fire the shots which killed the two victims. The defendant took the witness stand in his own behalf and testified that he did not commit the crime. He testified that the money found in his room represented his savings from a two-month period. He testified that the ammonia tracing could have been obtained at a different place since he worked as a delivery man and made deliveries to a number of grocery stores in the neighborhood. He testified that he had never fired a gun in his life. Based upon this evidence and assuming that guilt must be proven “beyond a reasonable doubt” would you find the defendant….

Scenario Used for Circumstantial Evidence + Eyewitness Testimony

+ Discredited Eyewitness On Friday, November 12, 1997, Mr. Smith, the owner of a small grocery store, was confronted by a man who demanded money from the cash register. Mr. Smith immediately handled $100 to the robber, who took the money and started walking away. Suddenly, and for no apparent reason, the robber turned and fired two shots at Mr. Smith and his five-year-old granddaughter, who was standing behind the counter. Mr. Smith and his granddaughter were hit and died instantly. Two-and-a-half hours later the police arrested a suspect who was charged with robbery and murder. A trial date was set for February 3, 1998. The prosecution presented evidence that indicated the robber was seen running from the store and into an apartment house nearby. The defendant was a resident of this apartment house. After executing a search warrant, the police found $123 in the defendant’s room. Traces of ammonia were found on the defendant’s shoes. Evidence was introduced that ammonia had been used to clean the floor of the store. Paraffin tests, used to determine whether a person has gunpowder particles on his hands from firing a gun, indicated that there was a slight possibility that the defendant had fired a gun during the day. A store clerk who was in the store during the robbery testified that she saw the defendant fire the shots which killed the two victims. The defendant took the witness stand in his own behalf and testified that he did not commit the crime. He testified that the money found in his room represented his savings from a two-month period. He testified that the ammonia tracing could have been obtained at a different place since he worked as a delivery man and made deliveries to a number of grocery stores in the neighborhood. He testified that he had never fired gun in his life. The defense showed that the store clerk had not been wearing her glasses on the day of the robbery, and since she had vision poorer than 20/400 without her glasses, she could not have possibly seen the face of the robber from where she stood. Based upon this evidence and assuming that guilt must be proven “beyond a reasonable doubt” would you find the defendant….

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