Charles Don Flores awaits his execution. He has been in prison for murder for more than 20 years after an eyewitness identified him as a perpetrator in a Texas court. In the first and second comparison, however, she had not recognized him. A research team from the USA warns that his case is just one example of many similar misjudgments. Only the first comparison counts – afterwards the memory is contaminated. In the case of Charles Don Flores, the witness’s statements speak for his innocence.
The group around the psychologist John Wixted from the University of California, including the well-known memory researcher Elizabeth Loftus, now wants to clarify this possible contamination. The focus is on the juxtaposition, a procedure that laypeople are mainly familiar with from US crime series: the investigators mix the suspect with several uninvolved people with whom he shares essential characteristics such as ethnic origin. Sometimes the people stand in a row behind a one-way window, sometimes only photos of them are presented. The victim or an eyewitness should say whether he recognizes the perpetrator in one of the people.
Already now there are guidelines for comparisons in order to avoid possible falsifications. For example, the witness should not have seen any media reports that could provide clues as to the suspect’s appearance. He must be informed that the perpetrator may not be among the people at all. And the investigators themselves must not know who the suspect is, in order not to unconsciously influence the witness.
But even if the comparison goes according to the rules of the art, the result can be wrong, write Wixted and his team. »A comparison leaves a memory trail on all faces, including that of the suspect. As a result, the memory of his face will react more strongly to the next confrontation, even if the person is innocent. “The more often the witness sees the suspect, the greater the risk of false identification and the more he thinks he can remember correctly which is often taken as an indication of a reliable statement in court. There is no way to “decontaminate” memory again.