By Duncan Brown, J.D.1

A recent New York state case, People v. Lee,2 is being interpreted by some as opening the floodgates for irresponsible expert testimony about the credibility and reliability of eyewitness identification. In reality, the court simply held that expert testimony is admissible at the discretion of the court.

Although the People v. Lee holding departs from earlier New York case law that held such testimony was per se inadmissible,3 for all practical purposes the decision does little more than align New York law with the practice of many jurisdictions in the nation. While the trend among courts has been to exercise broader discretion when deciding to admit eyewitness testimony experts, only a small minority of courts actually admits the testimony.4 Thus, while this type of expert testimony may not be per se excludable, few courts have been willing to use their discretion to do more than subsequently deny expert testimony after an evidentiary hearing.

Consequently, the Lee case does not mark a dangerous turning point in the status of the admissibility of experts who testify on the reliability of eyewitness identification. However, it does serve to put prosecutors on notice that courts are taking advantage of their discretion to consider the testimony of defense experts who rely on novel or controversial theories, such as eyewitness identification reliability. The following arguments have been used successfully to keep out expert testimony about the credibility and reliability of eyewitness identification.

Expert testimony about eyewitness identification impermissibly invades the role of the trier of fact in judging credibility and confuses the issue at trial.

The most common and obvious argument against admitting expert testimony about eyewitness identification is that it allows an expert to attack the credibility of a witness, thus usurping the jury of its duty to weigh the evidence as it sees fit. The argument also serves as a backbone for other arguments used to keep eyewitness experts off the witness stand. This argument has three underlying components: (1) understanding the reliability of eyewitness identification is within the general knowledge of the average juror; (2) testifying about an event at which the expert was not present impermissibly challenges the credibility of the actual eyewitness; and (3) the reports and studies relied upon by the expert are not specific enough to the particular case to be considered reliable and could confuse the issues at trial. These three components are discussed below.

First, the general requirement for any expert testimony is that it must substantially aid the jury in an issue that is beyond the knowledge or understanding of the average juror.5 Many courts recognize that the average juror is able to understand issues of credibility and reliability concerning eyewitness identification.6 One court has explicitly held that “the trustworthiness of eyewitness observations is not generally beyond the common knowledge and experience of the average juror and is, therefore, not a proper subject for expert testimony.”7

Most courts have followed suit, noting that the knowledge of the average juror, when complemented with observations of the witness during cross-examination and limiting instructions from the judge, is more than sufficient background for evaluating eyewitness testimony.8 When courts have held that an expert may be allowed, they have justified their reasoning by stating that certain, discrete issues about dynamics of eyewitness observation are beyond the ken of the average juror,9 or that particularities of the trial require it.10

Second, unfortunately, even in this limited function, the potential damage an expert can do is great because “any testimony about the reliability or accuracy of a witness’ identification [is] precariously close to expert testimony regarding the witness’ credibility as a witness.”11 By hiding behind the cloak of respectability afforded experts, the testimony can call into doubt the credibility of the witness’ observational or memory skills despite the fact that the expert did not observe the situation first hand as well. Other courts have recognized the danger of allowing an expert to testify about the credibility of a witness’ testimony, observing that the jury might place undue value on the expert’s testimony and “‘abandon its responsibility as fact finder and adopt the judgment of the expert,’ rather than ‘assist’ the jury in making its own determination of credibility.”12 One court has also held that because the subject of eyewitness testimony is so closely tied to issues of credibility, expert testimony on this subject could devolve into “battles between experts over the value of eyewitness identifications.”13

The third element of the general argument that expert testimony improperly invades the role of the jury is that the expert could offer needlessly complex or technical explanations for issues the jury can observe and weigh for themselves. Experts often fatally muddy the waters of the jury by improperly using their testimony to introduce theories that sound scientific, but in reality just confuse the jury in areas of general knowledge. Courts are careful to protect the jury from allowing expert testimony to infringe upon topics within the realm of common knowledge and understanding stating, “[t]he jury’s province is to weigh the credibility, and the court felt that where credibility is based on general factors, expert testimony is not needed.”14 Testimony based only on general factors or general knowledge has been found more confusing and prejudicial than probative because it is not applied to the specific case at hand nor does it address discrete issues raised by the defense.15

While some courts have held that expert testimony in this field is based entirely on junk science,16 the more prudent argument is that expert testimony is fatally flawed because it can improperly usurp the role of the jury by addressing issues of witness credibility when specifically applied. Additionally, expert testimony can also be irrelevant and confusing because it invades the province of the jury by attempting to make specific attacks on a witness’ credibility based only on generalized opinions and common knowledge of the reliability of eyewitness identification.

The opportunity to cross-examine the witness provides sufficient opportunity for the jury to judge the credibility of the witness.

Courts are reluctant to allow expert testimony about the credibility and reliability of eyewitness testimony because of the important role cross-examination plays in a jury’s duty of weighing evidence. Because eyewitness identification is within the general knowledge of the jury, and the jury has the ability to observe a witness answer questions and judge the quality of response, courts have consistently relied upon “[e]xtensive cross-examination of the eyewitness and persuasive argument by the defense counsel [to] highlight any inaccuracies which could result because the eyewitness was being threatened or under stress.”17

Courts have recognized that topics a defense expert could testify about can be properly addressed during cross-examination including, “problems associated with eyewitness identification, including many of the factors that could affect perception, retention, and recall.”18 Because of the ability of using cross-examination to “emphasize to the jury the eyewitness’s equivocations and possible mistakes,”19 expert testimony on the same subject is rendered redundant and irrelevant. Therefore, experts should be avoided because juries can “determine the reliability of eyewitness identification with the tools of cross-examination.”20

Proper limiting instructions by the court effectively address the issue of the reliability of eyewitness identification.

Limiting instructions by the court serve a similar function as cross-examination and have been held to be equally effective in addressing issues of eyewitness identifications.21 Because most courts believe that issues of eyewitness identification are within the understanding of the jury, jury instructions specifically tailored to the case that focus the jury’s attention on the witness’ ability to perceive and remember are sufficient.22 Courts have held that proper limiting instructions, coupled with cross-examination, can remove the need for experts on this subject altogether.23 Therefore, limiting instructions that properly charge the jury to weigh the evidence and consider all factors affecting reliability and credibility is more proper than the use of an expert because it does not infringe on the duties of the jury, nor does it confuse or muddle the ultimate issues at trial.

Corroborating evidence reduces the relevancy of eyewitness identification and renders expert testimony irrelevant.

One certain strategy to minimize the relevancy of expert testimony about the credibility and reliability of eyewitness testimony is to present corroborating evidence. Courts have held that “[g]enerally speaking, the existence of corroborating evidence undercuts the need, except in the most compelling cases, for expert testimony on eyewitness identifications.”24 Unless the issue of identity is dependent solely upon eyewitness identification, most jurisdictions will forgo the use of experts in favor of allowing the jury to weigh the witness’ testimony in relation to the evidence offered during trial.

Additionally, while most jurisdictions expect courts to weigh the need for an expert more carefully if there is no corroborating evidence,25 few reviewing courts are willing to question the lower court’s ultimate decision even in those circumstances.26 Thus, the need to thoroughly investigate and collect evidence is magnified by the potential benefit corroborating evidence has in cases involving eyewitness identification.27

The courts that allow expert testimony on eyewitness identification do so in very limited and specific instances.

The handful of jurisdictions that have admitted expert testimony about eyewitness identification do so only in limited circumstances. Most often, courts will be more willing to entertain expert testimony in cases where there is little corroborating evidence,28 or where there is compelling evidence to suggest that the testimony will be especially relevant or necessary.29 Even in these situations, the courts weighed the benefits and pitfalls of using experts rather than relying on the jury’s knowledge and ability. No jurisdiction has adopted a per se rule about when an expert’s testimony must be admitted. However, these rulings are not common and can be avoided by presenting corroborating evidence and proof that the proposed testimony is more prejudicial than probative.

Conclusion

Recent court rulings on the admissibility of expert testimony regarding the credibility and reliability of eyewitness testimony emphasize the amount of discretion the trial court has in deciding evidentiary issues. When taken with the new language of Federal Rule of Evidence 702, the trend appears to be toward protecting the role of juries to assess credibility. For now, the best defense to proposed expert testimony about eyewitness identification is that the jury is knowledgeable, the processes of cross-examination and jury instruction are informative and reliable, and the proposed expert testimony is too prejudicial and confusing to be of any substantial aid to the jury. However, prosecutors must be diligent in case preparation and procedure because defense attorneys are becoming more aggressive in their attempts to get experts on the stand. For more information on this subject, sample jury instructions or other materials, please contact the author at 703-519-1690.

1 Senior Attorney, APRI’s National Center for Prosecution of Child Abuse.
2 2001 N.Y.LEXIS 1061.
3 People v. Mooney, 76 N.Y.2d 827 (1980).
4 When courts have allowed experts to testify it has been for limited, case-specific reasons. See generally United States v. Burton, 1998 U.S. Dist.LEXIS 18730 (E.D.Tenn., 1998); United States v. Norwood, 939 F.Supp. 1132 (D.N.J., 1996); People v. Walker, 185 Cal.App.3d 155 (1986); United States v. Smithers, 212 F.3d 306; United States v. Hines, 55 F.Supp.2d 62; People v. Wright, 43 Cal.3d 399; United States v. Downing, 753 F.2d 1224.
5 Federal Rule of Evidence 702 states in part that “If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise…”
6 See generally Christie v. Kentucky, 2000 Ky.App.LEXIS 77 (2000); Weatherred v. Texas, 15 S.W. 3d 540 (2000); United States v. Crotteau, 218 F.3d 826 (7th Cir., 2000); United States v. Strode, 2000 U.S.App.LEXIS 15766 (9th Cir., 2000); Currie v. Virginia, 30 Va.App.58 (1999); United States v. Hall, 165 F.3d 1095 (7th Cir., 1999); Minnesota v. NMN, 585 N.W.2d 368 (1998); Green v. United States, 718 A.2d 1042 (1998); McMullen v. Florida, 714 So.2d 368 (1998); Dyer v. Arkansas, 1998 Ark.App.LEXIS 759 (1998); United States v. Smith, 122 F.3d 1355 (11th Cir., 1997); United States v. Rincon, 28 F.3d 921 (9th Cir., 1994).
7 Currie v. Virginia, 30 Va.App.58, 64.
8 McMullen v. State, 714 So.2d 368, 372 (1998).
9 These issues usually center on cross-racial identification, i.e. the identification of a person of one race by a witness of another. See United States v. Hines, 55 F.Supp.2d 62 (D.Mass., 1999); United States v. Smith, 736 F.2d 1103 (6th Cir., 1994); People v. Cronin, 60 N.Y.2d 430 at 432. However, one court has held that concepts such as how stress alters perception are well within the knowledge of the average juror. Dyer v. Arkansas, 1998 Ark.App.LEXIS 759, Currie v. Virginia, 30 Va.App.58.
10 United States v. Burton, 1998 U.S. Dist.LEXIS 18730; United States v. Norwood, 939 F.Supp. 1132; People v. Walker, 185 Cal.App.3d 155.
11 Kansas v. Gaines, 260 Kan. 752, 755 (1996).
12 State v. Coley, 32 S.W.2d 831, 835; citing State v. Ballard, 855 S.W.2d 557, 561 (1993).
13 Currie v. Virginia, 30 Va.App.58, 64.
14 Dyer v. Arkansas, 1998 Ark.App.LEXIS 759.
15 See State v. Coley, 32 S.W.2d at 837; Johnson v. State, 272 Ga. 254 (2000).
16 United States v. Rincon, 28 F.3d 921; Weatherred v. Texas, 15 S.W.3d 540.
17 State v. Gaines, 260 Kan. at 762; citing State v. Warren, 230 Kan. 385, 395 (1981).
18 United States v. Hall, 165 F.3d at 1105.
19 Green v. United States, 718 A.2d at 1053.
20 United States v. Smith, 122 F.3d at 1358.
21 One court in fact required jury instructions in cases where identity is a central issue. People v. Wright, 43 Cal.3d 399 (1987).
22 United States v. Hall, 165 F.3d at 1107.
23 United States v. Rincon, 28 F.3d at 925.
24 United States v. Hall, 165 F.3d at 1107.
25 See generally United States v. Smithers, 212 F.3d 306 (6th Cir., 2000); United States v. Hines, 55 F.Supp.2d 62 (D.Mass., 1999); People v. Wright, 43 Cal.3d 399 (1987); United States v. Downing, 753 F.2d 1224 (3rd Cir., 1985).
26 United States v. Walton, 217 F.3d 443, 449 (7th Cir., 2000).
27 For further reading on the importance of corroborating evidence and testimony see “When a Child Stands Alone: The Search for Corroborating Evidence” by Victor Vieth, Update Newsletter, Volume 12, Number 6 (1999).
28 See generally United States v. Smithers, 212 F.3d 306; United States v. Hines, 55 F.Supp.2d 62; United States v. Downing, 753 F.2d 1224.
29 United States v. Burton, 1998 U.S. Dist.LEXIS 18730; United States v. Norwood, 939 F.Supp. 1132; People v. Walker, 185 Cal.App.3d 155.