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Taking Measure
Just a Standard Blog
NIST researcher Carina Hahn's research led to some surprising findings about facial recognition research.
When investigators are working to solve a criminal case, they sometimes rely on experts who identify faces.
A forensic facial examiner’s job is to look at images or video footage of people (such as surveillance footage from a crime scene) and decide how likely it is that two images are of the same person.
But the scientific community is still working to understand how these professionals make their judgments. My research is working to do just that — in hopes that our knowledge can help with examiners’ education and training.
Testing Forensic Facial Examiners
Until fairly recently, the justice system and law enforcement lacked ways to test how skilled an examiner was.
That changed after a 2009 National Academy of Sciences report found that many forensic science disciplines were not supported by evidence. Since then, NIST researchers have been part of an effort to bring more scientific rigor to the field.
One of our efforts in response was to research the accuracy of forensic facial examiners.
Our research subsequently found that there are two groups of facial experts — including some who are naturally gifted at identifying faces and often can’t even explain how they do it so well. We call them “super-recognizers.” A second group is the forensic facial examiners who do this professionally. We believe the second group of experts has honed its abilities through experience and training. This is the group that I focused on in my latest research.
I wanted to answer the question: How does a face examiner identify a face? What is their process?
The answer might surprise you.
The Ears Have It
Our study required examiners to reveal only one part of the face at a time and try to identify someone. We wanted to see which parts of the face they were drawn to, as well as how accurate their analyses were when they focused on only those parts.
While the eyes may be the window to the soul, it wasn’t the eyes (or the nose or the mouth) that experts focused on. It was the ears.
You may not even think of a person’s ears as part of their face. But our research showed that examiners were more likely to be accurate when they saw only the ears than when they saw almost any other part of the face. Foreheads were also really helpful!
So, could you recognize someone based on only their ears? Maybe with a little training, you could too.
Why This Matters
I am passionate about researching facial recognition to promote both accuracy and transparency in the justice system.
In my research, I help facial examiners by providing evidence-based techniques for their work. If experts are using the same reliable and transparent methods, ideally, they should all reach very similar conclusions that are easily understood by judges and juries.
Becoming a Facial Recognition Researcher
As an undergraduate, I majored in psychology. I knew I was interested in people and their decision-making. One of my early research projects in school was to see how labeling someone as part of different groups changed how people saw that person’s face itself.
This intrigued me, and I wanted to learn more about how people perceive faces. I went to graduate school and studied how people learn and remember the faces of new people they meet. I studied their brain activity to see which parts of the brain are involved when we’re learning the face of someone new.
Faces fascinate me because our brains see and process faces differently from the way we perceive other objects. There are even regions in the brain for recognizing and viewing faces! And research shows that we make a lot of judgments about people, their personalities, and how trustworthy or even how competent they are based on their faces only. We rely on the face (often inaccurately) to make judgments about people so often.
You might be wondering if my research expertise means I am better at recognizing faces than anyone else. The answer is no — I actually forget faces pretty often. If you struggle with that as well, don’t worry; it happens to us researchers, too!
Facing the Future
I’m now working on future research projects to help us better understand different aspects of how forensic facial examiners work.
As a researcher, I am grateful to the examiners who voluntarily agree to participate in my research. I can imagine it’s nerve-wracking to have a researcher poke and prod into how you do your job, but the examiners we study are generous with their time and motivated to improve the field.
My goal is to continue to help these professionals do their jobs effectively — and make our justice system more transparent and accurate for all of us.
