Contextual bias on decision-making in forensic toxicology: First survey from China

In forensic science, contextual bias has been used to describe the tendency for a forensic analysis to be influenced by task-irrelevant background information. Contextual bias is not limited to subjective pattern matching disciplines based on visual recognition (e.g., fingerprints, handwritings, and tool marks), and has been demonstrated in objective analytical disciplines based on quantitative instruments (e.g., DNA typing). Recently, several publications suggested that contextual bias can even affect decision-makings in forensic toxicology. To obtain more extensive evidence of contextual bias, we surveyed 200 forensic toxicology practitioners from China for 1) unconscious bias in two hypothetical forensic toxicology cases with contextual information, 2) understanding of the concept and nature of contextual bias, 3) communication between investigators and forensic examiners, 4) and perception of the task-relevance of contextual information. The results revealed that 1) most of the participants made a decision deviating from standard processes under the potentially biasing context; 2) they also showed a low level of familiarity with the concept and nature of contextual bias; 3) they had a close contact with police investigators and even a dual role as a crime scene investigator and laboratory examiner, especially those affiliated with police departments; 4) and there was a general opinion that all available case information should be considered in the forensic toxicological analysis, even if the information should be specifically identified as task-irrelevant. As the first empirical work in China, this study attempted to draw more attention to the potential impact of Chinese forensic scientists' lack of appreciation of cognitive factors in forensic practice, and promote more extensive empirical research in various forensic domains.