EXPECTANCY EFFECTS IN FORENSIC EVIDENCE HANDLING: SOCIAL PSYCHOLOGICAL PERSPECTIVES

Expectancy effects in forensic evidence handling pose a serious threat to the validity of analyses conducted by forensic examiners. This questionable validity creates an impasse regarding key assumptions of law involving the admissibility of scientific and expert testimony. The history of specific rules of law governing the use of scientific evidence in the courtroom is detailed, followed by a review of social psychological concepts that provide a foundation for understanding how expectancy effects occur. The following review of theories of self and identity, and group theory will address the phenomena of expectancy effects from a social psychological perspective. This discussion emphasizes the need for review of forensic practices due to the human influence that examiners impart on the evidence, and the impact outside social forces exert on the examiners themselves. [PUBLICATION ABSTRACT]