But, in what’s been dubbed a biometric breakthrough, researchers have discovered that a person’s body shape could equally give them away.
Using just eight measurements, forensic teams were able to correctly identify people - even through clothes.
Dubbed ‘body recognition’, the technique was developed at the University of Adelaide, and is said to be comparable with facial and fingerprint analysis.
A team of researchers, led by PhD student Teghan Lucas, studied the anatomical measurements of 4,000 US armed services personnel from a national database.
In particular, they compared eight facial and eight body measurements to see if a person’s body shape could be used for identification.
Measurements included overall height, length of the body from the hip bone to the feet, length of wrist to elbow, jaw line, pelvic width, chest width, the width of a person’s face, from ear to ear, and the skull.
The breadth of hips across the 4,000 people studied varied by up to 5.9 inches (150mm), making an individual measurement more unique.
But, the length of ears across the sample varied by just 1.3 inches (35mm), making them harder to distinguish between.
Other measurements that can change, and were discounted in body recognition, include the width of the stomach, inner arm and calf.
These areas are directly affected by weight gain and loss, for example.
During tests, the results revealed that, compared with the face, fewer body measurements are needed to identify a person.
‘There's been a lot of work conducted over the years on facial recognition,’ said Ms Lucas.
This makes sense - humans have evolved to recognise faces, which is part of our survival mechanism, and the face contains some very distinctive features.
‘But what happens if the face is not shown, or if there is an unusual facial resemblance between two people?
'What happens if identification of the face alone just isn't enough?’
She continued that the technique would prove particularly useful when trying to identify criminals, or missing persons, from CCTV footage, for example.
‘Measurements of the body, as well as the face, were used for forensic identification as early as the 19th century,' continued Ms Lucas.
'It was believed that no two individuals had the exact same measurements.
‘However, this was overtaken by fingerprint analysis because it was considered more reliable in court proceedings, and the probability of finding matching individuals could be easily calculated.’
Ms Lucas’ research discovered that, with a combination of eight body measurements, it is possible to reduce the probability of finding a duplicate to the order of one in a quintillion.
This makes the results comparable with fingerprint analysis, she added.
The larger the range of each of the measurements, the less chance there is of finding a duplicate, too, and the measurements can be identified no matter what clothing the person may be wearing.
This is because the way gravity affects the overall body shape remains unchanged, and any movements - such as those on security footage - will reveal the outline of a body.
For example, once fully formed, an adult's skeleton changes very little over the course of their life.
The length of the femur, or the proportions from the wrist to the elbow, don’t change until a person becomes elderly.
The larger measurements provided by the body compared to the face mean that there is more variation between people.
‘Despite what television and the movies would have people believe, there is often a lack of good quality video evidence,’ said Ms Lucas.
‘Criminal cases usually involve a deliberate attempt to cover the face, or fine details can't be seen.
‘In our experience, the body is more variable than the face and should be used in identification more often.
‘Another advantage to using the body is that larger dimensions are easier to locate on images and not affected by facial expressions.’
YOUR BODY SHAPE IS UNIQUE: The researchers studied the anatomical measurements of 4,000 US armed services personnel from a national database.
In particular, they compared eight facial and eight body measurements to see if a person’s body shape could be used for identification.
Measurements included overall height, length of the body from the top of the hip bones to the feet, length of wrist to elbow, jaw line, pelvic width, chest width, the width of a person’s face, from ear to ear, and the skull.
The breadth of hips across the sample studied varied by up to 5.9 inches (150mm), making an individual measurement more unique.
But, the length of ears across the sample varied by just 1.3 inches (35mm), making them harder to distinguish between.
Other measurements that can change, and were discounted in body recognition, include the width of the stomach, inner arm and calf. These areas are directly affected by weight gain and loss, for example.
During tests, the results revealed that, compared with the face, fewer body measurements are needed to identify a person.
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