Medical examiners may not be immune to bias

Should forensic scientists know as little or as much as possible about the facts of the underlying case?

An article from the University of California, Irvine, school of law addresses this question and presents the following anecdote:

An evolutionary biologist studying the lineage of the Australian finch utilizes DNA testing to determine whether more brightly colored males mate more and produce more young and whether the male in a bonded pair is always the father of his partner’s offspring.

The biologist is adamant that DNA test results must be examined blind (the scientist can’t know, for instance, which birds are a bonded pair when determining offspring lineage) because it’s human nature to seize upon evidence that supports the investigator’s hypothesis and minimize or discredit evidence to the contrary.

Because the danger of bias is well-known, a scientist using less rigorous procedures would never be able to obtain financial support or publish in peer-review journals, the biologist says.

The interpretation of forensic evidence often has a major influence on the outcome of criminal prosecutions, so it’s extremely important, too, but rarely do forensic scientists interpret evidence blind.

They usually know the basic facts and nature of the case, and they understand how their determinations will influence the investigation and the likelihood of successful prosecution.

Link: http://durangoherald.com/article/20110509/COLUMNISTS09/705099988/-1/s