The advent of DNA testing has made it uncomfortably clear that our criminal justice system often gets things wrong. Articles are wrong for many reasons, but most of them involve science, or rather the lack of a scientific basis for a number of investigative techniques. But in 70 percent of cases where DNA overturns a conviction, it also contradicts the testimony of one or more eyewitnesses to the events that occurred.
According to a new perspective published PNAS, should not surprise us. The book’s author, Salk neuroscientist Thomas Albright, argues that much has been learned about how people perceive the world, process information, and retain memories. And many of them show that we should not appreciate the evidence we see as we do. However, Albright offers some suggestions about how to adapt the research process to compensate somewhat for human limitations.
Endurance of memory
Albright has some history in this area, as he chaired a group at the National Academies on the subject. His new appearance is a very brief one the news That’s the result of the group, and it’s an important reminder that we have sound, evidence-based recommendations for improving the criminal justice system. Failure to do so many years after the report is problematic.
Apparently, things go wrong for the witnesses from the beginning. While human vision is good, there are many conditions—low light, distance, and shadowy actions—that make it difficult to see exactly what’s going on. And we don’t always focus on things that will make us good witnesses; if someone is waving a gun around, we tend to look at the gun, not their eyes. And even if they don’t throw a gun, we can believe that they are if the visual information we remember is vague, but we know that a robbery is happening.
Confronted with partial information, research indicates that our brain’s response is not to commit the type of information we have to memory. Instead, our brain tries to create a coherent image that makes sense. This often involves filling in details using past experience as a guide. The resulting memory may be reasonably accurate, but may come at the cost of incorrect information.
Memory is also remarkably malleable. Rather than being stored unaltered in our hippocampus, several studies show that the mere act of remembering something can cause its memory to be updated (or, in some cases, lost). And there is a good chance that witnesses will be asked to recall the events several times before they are finally called to testify in court. Usually, one of those moments involves seeing the lineup, either in person or through photos. This can leave a witness open to suggestions by suspicious researchers—suggestions that can be used to influence the memory.
By the time someone testifies at trial, their confidence in their memory of relevant events is not dependent on whether they can remember them correctly. Instead, it’s mostly turned into confidence about whether they can put together a coherent picture of what happened, which is not the same thing. (Albright quotes the philosopher Dan Kahneman as saying, “The most reliable statements tell you that each person has written a story that fits in their mind, not that the story is true.”) Still for a jury, the credibility of the witnesses is intact. to be an important part of evaluating the credibility of a witness.
That is not to say that no eyewitness memory is reliable or that our judicial system’s reliance on their testimony is completely wrong. Instead, Albright cited a National Institutes of Health report arguing that the justice system needs to do more to take memory limits into account. And police departments can implement procedures meant to limit their influence on a witness’s memory.
Albright cautioned that research in some areas is still in flux. For example, early research praised the use of sequences, in which possible perpetrators are shown individually, because it cuts down on false identification. But subsequent work shows that the method cuts through all identities, false or correct. Now, the pendulum has swung back toward simultaneous viewing.
That said, some modifications of the report recommend focusing on a key point in the process: the first identification in the police lineup. He called the process “blind,” meaning that the police on duty were not involved in the case and had no idea about who the potential suspect might be. The process should be videotaped, and the credibility of the witness in the identification should be verified at that time. (Albright cites a case where a person who was uncertain in the lineup then went on to show complete certainty in their mistaken identity in court.)
Courts can also be influenced by the instructions they give to both witnesses and jurors. Witnesses can be instructed in ways that help provide accurate and conservative answers and with a sense of uncertainty. Jurors may be told some of the limitations of witness testimony.
Albright is somewhat optimistic about the potential for change, pointing to two recent state court decisions that advance the scientific basis for admissibility of eyewitness testimony. But he noted that for federal courts, the Supreme Court set the standard for pretrial witnesses in 1977, and it is based on legal theory rather than science. There are no obvious ways to update that standard.
But ultimately, the most important recommendations in the report have to be implemented at the level of thousands of individual police departments across the country. While the courts can help drive that process, change will only be possible if these sectors have equal value over the possible possibility of receiving any kind of recognition.
PNAS2017. DOI: 10.1073/pnas.1706891114 (About DOIs).