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Is Crime Forensics Flawed?
Forget everything you think you learned on your favorite crime scene drama.
Attorney General Jeff Sessions recently announced he will not renew the National Commission on Forensic Science (NCFS), an Obama-era body investigating the soundness of forensic techniques. This is concerning because in recent years, time honored methods such as fingerprinting, hair and fiber analysis, firearm analysis, and others, have come under intense scrutiny.
Sessions plans to replace the commission with an internal body called the department crime task force, headed by a senior forensic adviser who will report to him directly. No one has been named for the position as of yet.
While supports say this will help in the effort to cut backlogs and winnow down processing times within crime labs, critics argue that it’s just another example of the Trump administration reducing the role of science, particularly independent science, in policy-making. So how reliable are these methods and do they really need closer scrutiny?
Since 1989, DNA evidence has exonerated 329 individuals. Bite mark and hair analysis—part of what is known as pattern forensics, helped convict 25% of them. These were convictions for murder, rape, and other violent crimes, stretching back to the 1970s.
The FBI’s crime lab is the most advanced in the world. Yet, shockingly, in 2002 the nation’s top law enforcement agency reported that through DNA testing, they found that hair analysis was wrong 11% of the time—a technique replied upon for decades.
Though a mainstay of the TV crime drama, firearm analysis has been found flawed. Getty images.
In 2005, the FBI abandoned comparative bullet lead analysis. At least three convictions where FBI experts provided testimony were overturned, all for murder. This was based on the idea that lead bullets pick up traces of elements in manufacturing. Bullet fragments therefore could be tracked down using a small nuclear reactor housed in a special FBI lab in the Hoover Building. Only a few specially trained agents could use it.
It was thought that gamma rays could determine the makeup of the bullet and so whether or not it was a match to others owned by the alleged perpetrator. This technique began in the mid-1960s.
But in 2005, the National Research Council of the National Academy of Sciences, concluded that it was flawed. Millions of other bullets could match one within a particular victim’s body, meaning other bullets possessed by the same person could not be matched to the murder weapon.
A 2009 report by the National Research Council made sweeping changes to crime forensics worldwide. It found pretty much every forensic science technique inherently flawed. With bite mark matching, the National Research Council argued that no studies back up that human dentition is unique to each individual. It also hasn’t been proven that human skin can take an accurate impression of a person’s teeth.
Bite mark evidence has led to 21 wrongful convictions, yet hasn’t been barred by any court. Bite mark matching isn’t alone. No studies have backed up shoe tread or tire tread analysis either.
An over-reliance on uncertain methods has led to wrongful convictions historically. Getty Images.
One of the most commonly believed “facts” is that everyone’s fingerprints are unique and can be objectively identified. A perfect, whole print must be attained for the evidence to be reliable. Even so, it hasn’t even been established that everyone’s fingerprints are unique, according to the National Academies of Sciences. Because of this, no reliable experts will testify that fingerprint evidence has an error rate of zero.
Now for firearms matching, not enough research has been conducted to conclude that a bullet’s marks are caused by a specific gun. Experts haven’t even developed a uniform method to perform firearm analysis.
Bloodstain pattern analysis was also found arbitrary, sorry Dexter fans, as was handwriting analysis. DNA analysis however remains the only objective method. But there are lots of caveats including how it’s collected and how long it’s been stored.
In 2015, the Justice Department acknowledged that almost everyone in the FBI’s microscopic hair comparison unit gave false testimony, in nearly all the trials where such analysis was used, 268 in all. These took place between the 1970's and 2000. 32 of the defendants were given the death penalty. 14 either died in prison or were executed.
A standardization of practices and the inclusion of more scientists could improve the situation. Getty Images.
Some scientists say that pattern forensics was developed by detectives and criminal justice experts, not scientists, and so these methods are flawed. They argue that the only way to improve the system, is to give forensic scientists more power and voice, making law enforcement officials take a back seat.
In the two years of its existence, the NCFS instituted 43 standards including: certification rules for crime lab workers, better reporting standards, and updated discovery rules. Still, many state and federal law enforcement officials chaffed at the idea of additional oversight. As Attorney General Sessions announcement demonstrates, things are moving us back in the other direction.
Brandon L. Garrett is a law professor at the University of Virginia. He said there are glaring flaws in the criminal justice system, such as courts allowing precedents that are questionable or testimony that isn’t scientifically sound.
Prof. Garrett commended the FBI for speaking out, saying many attorneys and judges are unable or unwilling to. The long and the short of it is, “The tools don’t exist to handle systematic errors in our criminal justice system,” according to Garrett.
It’s important to note that the National Commission on Forensic Science isn’t the only body in the federal government that examines the science behind crime forensics. The National Institute of Standards and Technology (NIST) does so.
It’s established working groups such as the Organization of Scientific Area Committees (OSACs), comprised of scientists and other experts who are examining nearly 30 crime forensic techniques, currently. Some experts wonder whether these are on the chopping block or will soon be replaced, as well.
To learn more about the flaws in crime forensics, click here:
Why mega-eruptions like the ones that covered North America in ash are the least of your worries.
- The supervolcano under Yellowstone produced three massive eruptions over the past few million years.
- Each eruption covered much of what is now the western United States in an ash layer several feet deep.
- The last eruption was 640,000 years ago, but that doesn't mean the next eruption is overdue.
The end of the world as we know it
Panoramic view of Yellowstone National Park
Image: Heinrich Berann for the National Park Service – public domain
Of the many freak ways to shuffle off this mortal coil – lightning strikes, shark bites, falling pianos – here's one you can safely scratch off your worry list: an outbreak of the Yellowstone supervolcano.
As the map below shows, previous eruptions at Yellowstone were so massive that the ash fall covered most of what is now the western United States. A similar event today would not only claim countless lives directly, but also create enough subsidiary disruption to kill off global civilisation as we know it. A relatively recent eruption of the Toba supervolcano in Indonesia may have come close to killing off the human species (see further below).
However, just because a scenario is grim does not mean that it is likely (insert topical political joke here). In this case, the doom mongers claiming an eruption is 'overdue' are wrong. Yellowstone is not a library book or an oil change. Just because the previous mega-eruption happened long ago doesn't mean the next one is imminent.
Ash beds of North America
Ash beds deposited by major volcanic eruptions in North America.
Image: USGS – public domain
This map shows the location of the Yellowstone plateau and the ash beds deposited by its three most recent major outbreaks, plus two other eruptions – one similarly massive, the other the most recent one in North America.
The Huckleberry Ridge eruption occurred 2.1 million years ago. It ejected 2,450 km3 (588 cubic miles) of material, making it the largest known eruption in Yellowstone's history and in fact the largest eruption in North America in the past few million years.
This is the oldest of the three most recent caldera-forming eruptions of the Yellowstone hotspot. It created the Island Park Caldera, which lies partially in Yellowstone National Park, Wyoming and westward into Idaho. Ash from this eruption covered an area from southern California to North Dakota, and southern Idaho to northern Texas.
About 1.3 million years ago, the Mesa Falls eruption ejected 280 km3 (67 cubic miles) of material and created the Henry's Fork Caldera, located in Idaho, west of Yellowstone.
It was the smallest of the three major Yellowstone eruptions, both in terms of material ejected and area covered: 'only' most of present-day Wyoming, Colorado, Kansas and Nebraska, and about half of South Dakota.
The Lava Creek eruption was the most recent major eruption of Yellowstone: about 640,000 years ago. It was the second-largest eruption in North America in the past few million years, creating the Yellowstone Caldera.
It ejected only about 1,000 km3 (240 cubic miles) of material, i.e. less than half of the Huckleberry Ridge eruption. However, its debris is spread out over a significantly wider area: basically, Huckleberry Ridge plus larger slices of both Canada and Mexico, plus most of Texas, Louisiana, Arkansas, and Missouri.
This eruption occurred about 760,000 years ago. It was centered on southern California, where it created the Long Valley Caldera, and spewed out 580 km3 (139 cubic miles) of material. This makes it North America's third-largest eruption of the past few million years.
The material ejected by this eruption is known as the Bishop ash bed, and covers the central and western parts of the Lava Creek ash bed.
Mount St Helens
The eruption of Mount St Helens in 1980 was the deadliest and most destructive volcanic event in U.S. history: it created a mile-wide crater, killed 57 people and created economic damage in the neighborhood of $1 billion.
Yet by Yellowstone standards, it was tiny: Mount St Helens only ejected 0.25 km3 (0.06 cubic miles) of material, most of the ash settling in a relatively narrow band across Washington State and Idaho. By comparison, the Lava Creek eruption left a large swathe of North America in up to two metres of debris.
The difference between quakes and faults
The volume of dense rock equivalent (DRE) ejected by the Huckleberry Ridge event dwarfs all other North American eruptions. It is itself overshadowed by the DRE ejected at the most recent eruption at Toba (present-day Indonesia). This was one of the largest known eruptions ever and a relatively recent one: only 75,000 years ago. It is thought to have caused a global volcanic winter which lasted up to a decade and may be responsible for the bottleneck in human evolution: around that time, the total human population suddenly and drastically plummeted to between 1,000 and 10,000 breeding pairs.
Image: USGS – public domain
So, what are the chances of something that massive happening anytime soon? The aforementioned mongers of doom often claim that major eruptions occur at intervals of 600,000 years and point out that the last one was 640,000 years ago. Except that (a) the first interval was about 200,000 years longer, (b) two intervals is not a lot to base a prediction on, and (c) those intervals don't really mean anything anyway. Not in the case of volcanic eruptions, at least.
Earthquakes can be 'overdue' because the stress on fault lines is built up consistently over long periods, which means quakes can be predicted with a relative degree of accuracy. But this is not how volcanoes behave. They do not accumulate magma at constant rates. And the subterranean pressure that causes the magma to erupt does not follow a schedule.
What's more, previous super-eruptions do not necessarily imply future ones. Scientists are not convinced that there ever will be another big eruption at Yellowstone. Smaller eruptions, however, are much likelier. Since the Lava Creek eruption, there have been about 30 smaller outbreaks at Yellowstone, the last lava flow being about 70,000 years ago.
As for the immediate future (give or take a century): the magma chamber beneath Yellowstone is only 5 percent to 15 percent molten. Most scientists agree that is as un-alarming as it sounds. And that its statistically more relevant to worry about death by lightning, shark, or piano.
Strange Maps #1041
Got a strange map? Let me know at firstname.lastname@example.org.
The potential of CRISPR technology is incredible, but the threats are too serious to ignore.
- CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a revolutionary technology that gives scientists the ability to alter DNA. On the one hand, this tool could mean the elimination of certain diseases. On the other, there are concerns (both ethical and practical) about its misuse and the yet-unknown consequences of such experimentation.
- "The technique could be misused in horrible ways," says counter-terrorism expert Richard A. Clarke. Clarke lists biological weapons as one of the potential threats, "Threats for which we don't have any known antidote." CRISPR co-inventor, biochemist Jennifer Doudna, echos the concern, recounting a nightmare involving the technology, eugenics, and a meeting with Adolf Hitler.
- Should this kind of tool even exist? Do the positives outweigh the potential dangers? How could something like this ever be regulated, and should it be? These questions and more are considered by Doudna, Clarke, evolutionary biologist Richard Dawkins, psychologist Steven Pinker, and physician Siddhartha Mukherjee.
Measuring a person's movements and poses, smart clothes could be used for athletic training, rehabilitation, or health-monitoring.
In recent years there have been exciting breakthroughs in wearable technologies, like smartwatches that can monitor your breathing and blood oxygen levels.
But what about a wearable that can detect how you move as you do a physical activity or play a sport, and could potentially even offer feedback on how to improve your technique?
And, as a major bonus, what if the wearable were something you'd actually already be wearing, like a shirt of a pair of socks?
That's the idea behind a new set of MIT-designed clothing that use special fibers to sense a person's movement via touch. Among other things, the researchers showed that their clothes can actually determine things like if someone is sitting, walking, or doing particular poses.
The group from MIT's Computer Science and Artificial Intelligence Lab (CSAIL) says that their clothes could be used for athletic training and rehabilitation. With patients' permission, they could even help passively monitor the health of residents in assisted-care facilities and determine if, for example, someone has fallen or is unconscious.
The researchers have developed a range of prototypes, from socks and gloves to a full vest. The team's "tactile electronics" use a mix of more typical textile fibers alongside a small amount of custom-made functional fibers that sense pressure from the person wearing the garment.
According to CSAIL graduate student Yiyue Luo, a key advantage of the team's design is that, unlike many existing wearable electronics, theirs can be incorporated into traditional large-scale clothing production. The machine-knitted tactile textiles are soft, stretchable, breathable, and can take a wide range of forms.
"Traditionally it's been hard to develop a mass-production wearable that provides high-accuracy data across a large number of sensors," says Luo, lead author on a new paper about the project that is appearing in this month's edition of Nature Electronics. "When you manufacture lots of sensor arrays, some of them will not work and some of them will work worse than others, so we developed a self-correcting mechanism that uses a self-supervised machine learning algorithm to recognize and adjust when certain sensors in the design are off-base."
The team's clothes have a range of capabilities. Their socks predict motion by looking at how different sequences of tactile footprints correlate to different poses as the user transitions from one pose to another. The full-sized vest can also detect the wearers' pose, activity, and the texture of the contacted surfaces.
The authors imagine a coach using the sensor to analyze people's postures and give suggestions on improvement. It could also be used by an experienced athlete to record their posture so that beginners can learn from them. In the long term, they even imagine that robots could be trained to learn how to do different activities using data from the wearables.
"Imagine robots that are no longer tactilely blind, and that have 'skins' that can provide tactile sensing just like we have as humans," says corresponding author Wan Shou, a postdoc at CSAIL. "Clothing with high-resolution tactile sensing opens up a lot of exciting new application areas for researchers to explore in the years to come."
The paper was co-written by MIT professors Antonio Torralba, Wojciech Matusik, and Tomás Palacios, alongside PhD students Yunzhu Li, Pratyusha Sharma, and Beichen Li; postdoc Kui Wu; and research engineer Michael Foshey.
The work was partially funded by Toyota Research Institute.