PA SUPREME COURT LIFTS ITS BAR ON EXPERT TESTIMONY REGARDING EYEWITNESS IDENTIFICATION
Earlier this week, the Pennsylvania Supreme Court issued an opinion reversing its prior precedent and opening the door for the admission of expert testimony in the area of eyewitness identifications. The decision in Commonwealth v. Benjamin Walker stems from a robbery in Philadelphia, for which Walker was convicted primarily on the basis of eyewitness testimony. During trial, Walker attempted to present expert testimony regarding the unreliability of eyewitness identification, however the trial court excluded it based on unequivocal Pa. Supreme Court precedent that held such testimony was per se impermissible. The Superior Court affirmed.
The Pa. Supreme Court granted allocator and reversed, lifting its per se ban on expert testimony on eyewitness identification and remanding the case to the trial court for a Frye hearing. The Court first recognized that while eyewitness evidence may be extremely probative, it can be fallible and untrustworthy, and “there is no doubt that wrongful conviction due to erroneous eyewitness identification continues to be a pressing concern for the legal system and society.” The Court suggested that one way to assist fact finders in making more accurate and just determinations is through the admission of expert testimony. The Court then turned to the “considerable empirical research that has been conducted regarding eyewitness identification,” and which has been developed over the last 20 years (since Pennsylvania’s per se ban was established). The Court also noted that expert testimony on eyewitness identification has gained acceptance by the vast majority of state and federal courts (Pennsylvania, Kansas and Louisiana were the only states following a per se exclusionary approach). The Court also dismissed concerns that allowing such expert testimony would invade the jury’s province of making credibility determinations – finding that such testimony, in reality, educates the jury and allows them to engage in credibility determinations with full awareness of the limitations of eyewitnesses.
In its opinion, the Court attempted to set forth some limitations to the use of expert testimony in the area of eyewitness identification. First, such expert testimony should be permitted only where relevant – generally, where the Commonwealth’s case is solely or primarily dependent upon eyewitness testimony. The Court discussed relevance in the context of the case against Walker – where there was no direct evidence other than eyewitness identifications, where Walker was the subject of cross-racial identification, where the witnesses were under stress having been robbed at gunpoint, where the police did not instruct the witnesses that the suspect may or may not be included in the photo array, and where one witness equivocated during her original identification but was more confident at trial. According to the Court, the defendant must make an on-the-record detailed proffer, explaining the presence of factors which may be shown to impair the accuracy of eyewitness identification and which are beyond the common understanding of laypersons.
This decision marks a dramatic shift for the Pa. Supreme Court and will likely have a remarkable effect on the prosecution and defense of criminal cases based on eyewitness identifications. One thing we know for sure, social psychologists in Pennsylvania rejoice!