Study Raises Questions about Longstanding Forensic Identification Technique

Forensic experts have long used the shape of a person’s skull to make positive identifications of human remains. But those findings may now be called into question, since a new study from North Carolina State University shows that there is not enough variation in skull shapes to make a positive ID.

“In a lot of cases, murder victims or the victims of disasters are from lower socioeconomic backgrounds and don’t have extensive dental records we can use to make a match,” says Dr. Ann Ross, a forensic expert and professor of anthropology at NC State who is senior author of a paper on the new study. “But those people may have been in car accidents or other incidents that led them to have their skulls X-rayed in emergency rooms or elsewhere. And those skull X-rays have often been used to make IDs. I’ve done it myself.

“But now we’ve tried to validate this technique, and our research shows that the shape of the skull isn’t enough to make a positive ID,” Ross says.

At issue is the “cranial vault outline,” not the “face” of the skull. The cranial vault outline is the profile of the skull when viewed from the side, running from just above the bridge of the nose to the point where the skull and neck meet.

For the study, the researchers surveyed 106 members of the American Academy of Forensic Sciences. Survey participants were asked to evaluate 14 antemortem X-rays and five postmortem X-rays. Participants were then asked to match the 5 postmortem X-rays with the appropriate antemortem X-ray, effectively establishing a positive ID.

But the researchers found that only 47 percent of the participants made accurate identifications on all five skulls. Participants who have Ph.D.s did slightly better, with 56 percent of them getting all five correct. (The test has been made available here so that anyone can take it.)

“This doesn’t mean that cranial vault outlines aren’t useful,” says Ashley Maxwell, lead author of the paper and a former graduate student at NC State. “For example, outlines can be valuable if teeth or other features are missing or have been destroyed. But it does mean that cranial vault outlines shouldn’t be given too much weight.

“The more characteristics we can take into account, such as facial features and cranial vault outlines, the more accurate we can be,” Maxwell says.

Neuroscience - the science of the brain and how it works - is taking the stand and beginning to challenge society’s notions of crime and punishment.

Experts say it’s almost inevitable that neuroscience and law will become yet more intertwined. After all, while neuroscience seeks to find out how the brain functions and affects behavior, the law’s main concern is with regulating behavior. Yet many are uneasy about the use in courts of law - and in matters of life and death - of basic science that is only just creeping out of the lab.

"All sorts of types of neuroscience evidence are being used for all sorts of types of claims," says Teneille Brown, a professor of law at the University of Utah. "The question is, is this technology really ready for prime time, or is it being abused? … Neuroscience is being used by serious scientists in real labs, but the people trying to apply it in courts are not those same people … So they’re taking something that looks very objective, that looks like gold standard science, but then morphing it into a forensic use it wasn’t developed for."

Science of Eyewitness Memory Enters Courtroom

Science has prevailed over injustice in the state of New Jersey, where all jurors will soon learn about memory’s unreliability and the limits of eyewitness testimony.

According to instructions issued July 19 by New Jersey’s Supreme Court, judges must tell jurors that “human memory is not foolproof,” and enumerate the many ways in which eyewitness recall can be distorted or mistaken.