Opinion ID: 2559587
Heading Depth: 1
Heading Rank: 2

Heading: Proffered Expert Evidence

Text: At trial, defense counsel sought to call as an expert Dr. Lori Van Wallendael, a university professor of cognitive psychology with specialized experience in eyewitness perception and memory. [3] He asserted that Dr. Wallendael would testify about the factors present in this case that are known to affect adversely eyewitness perception, memory, and identification. He also stated that the professor's area of expertise was a well-established field, that the subject areas are supported by extensive research and have broad acceptance in the scientific community, and that she had been qualified to testify in these areas in the Superior Court of the District of Columbia and in other jurisdictions. The defense proffered that the expert would testify that: (1) there is little correlation between a witness' level of confidence and the accuracy of the identification; (2) police officers perform no better than lay witnesses in witness identifications; (3) the presence of a weapon adversely affects the witness' ability to focus and remember the face of the perpetrator; (4) presenting a suspect in clothing similar to that of the perpetrator undermines the reliability of the identification, an effect known as clothing bias; and (5) post-event information (contamination) leads to distortions and memory errors. In the trial court, the government challenged the admissibility of appellant's expert's testimony principally on the ground that it did not meet the first Dyas factor. Specifically, the government argued that the subject matter of the proffered testimony was within the common experience of every juror and that defense counsel could probe on cross-examination and present argument on the matters he sought to bring out through the expert. The trial court concluded that none of the subject areas were beyond the ken of lay jurors to understand, evaluate, and to deal with effectively through cross-examination, and therefore, it excluded the evidence.