Letting Eyewitnesses Sleep Could Make For More Accurate Testimony

iStock
iStock

Despite what watching Law & Order might have taught you, eyewitness accounts of crimes are far from trustworthy. Human memory is fallible, and in fact, eyewitnesses are notoriously bad at providing accurate evidence. Misidentification by eyewitnesses has played a role in 70 percent of convictions overturned by DNA evidence in the U.S., according to the New York-based Innocence Project. But a new study suggests one way to help eyewitnesses provide more accurate evidence: sleep.

Published in the journal PLOS ONE and spotted by Futurity, the study finds that witness testimony is more accurate during police lineups if the person is well-rested.

In the study, Michigan State University students watched a video of a staged crime in which a man planted a bomb on a rooftop. They were then asked to look through several black-and-white lineups of six people, some of which included the perpetrator from the video, and some of which only had look-alike fillers. The participants had to wait 12 hours between watching the video and picking out the criminal from the lineup, but not all of them spent it the same way. Some watched the video in the morning and looked at the lineup at night, while others watched the video at night and then looked at the lineup in the morning, after they had slept.

The researchers found that when participants slept between seeing the “crime” and being presented with potential suspects, they were less likely to pick someone out of lineups that only included fillers. In other words, they were better able to reject innocent lookalikes, noting correctly that the perpetrator they had seen wasn’t present at all. People who had not slept misidentified an innocent person as the perpetrator 66 percent of the time compared to 42 percent of the people who had slept. That doesn’t seem like a huge difference, but even one misidentification in real life can have serious consequences for innocent people accused of crimes. The results track with existing research on sleep that has found that it plays an important role in cognitive processes like learning and memory.

However, sleep didn’t make the participants any better at identifying the correct suspect when he was in the lineup. Both groups could pick him out with about 50 percent accuracy. Essentially, sleep isn’t going to solve crimes, but it could help ensure that the wrong person doesn’t go to prison.

Previously, a 2016 study in Psychological Science found that it’s relatively easy for police to nudge witnesses into picking their prime suspect from a lineup by making sure that they’re the only person in the group with a particular distinguishing feature, like a beard. These unfair lineups not only resulted in misidentification, but participants who chose from them were more confident about their (incorrect) choice than people who saw more fair lineups.

Taking a long nap isn’t the only way to improve lineup accuracy. The criminal justice advocates at the Innocence Project recommend several methods to make sure that witness testimony is more accurate, such as making sure that the people shown in the lineups all roughly match the description of suspect (beard and all), having the lineup administered by an officer who doesn’t know which person in the lineup is the police’s suspect, and making sure the witnesses know that the perpetrator might not be in the lineup at all, and that the investigation will continue even if they don’t pick anyone.

[h/t Futurity]

Do Dogs Understand What You’re Telling Them? Scientists Are Scanning Their Brains to Find Out

iStock/kozorog
iStock/kozorog

We all know that dogs can learn to respond to human words, but it’s not always clear what’s happening in a dog’s brain when they hear and recognize words like “cookie” and “fetch.” Do they have to rely on other clues, like gestures, to figure out what we mean by that word? Do they picture a dog biscuit when you say “cookie,” or just the sensation of eating? In a new study, scientists from Emory University and the New College of Florida tried to get to the bottom of this question by training dogs to associate certain objects with words like “blue” and “duck,” then using fMRI brain scanners to see what was happening in the dogs’ heads when they heard that word.

The study, published in Frontiers in Neuroscience, examined the brains of 12 different dogs of various breeds (you can see them below) that had been trained to associate two different objects with random words like “duck,” “blue,” and “beach ball.” Those two objects, which were different for each dog, were brought by the dogs’ owners from home or chosen from a selection of dog toys the researchers compiled. One object had to be soft, like a stuffed animal, and the other one had to be something hard, like a rubber toy or squeaky toy, to make sure the dogs could clearly distinguish between the two. The dogs were trained for several months to associate these objects with their specific assigned words and to fetch them on command.

Then, they went into the fMRI machine, where they had been trained to sit quietly during scanning. The researchers had the dogs lie in the machine while their owners stood in front of them, saying the designated name for the toys and showing them the objects. To see how the dogs responded to unknown words, they also held up new objects, like a hat, and referred to them by gibberish words.

Dogs in a science lab with toys
Prichard et al., Frontiers in Neuroscience (2018]

The results suggest that dogs can, in fact, discriminate between words they know and novel words. While not all the dogs showed the same neural response, they showed activation in different regions of their brains when hearing the familiar word versus the novel one.

Some of the dogs showed evidence of a greater neural response in the parietotemporal cortex, an area of the dog brain believed to be similar to the human angular gyrus, the region of the brain that allows us to process the words we hear and read. Others showed more neural activity in other regions of the brain. These differences might be due to the fact that the study used dogs of different sizes and breeds, which could mean differences in their abilities.

The dogs did show a surprising trend in their brains’ response to new words. “We expected to see that dogs neurally discriminate between words that they know and words that they don’t,” lead author Ashley Prichard of Emory University said in a press release. “What's surprising is that the result is opposite to that of research on humans—people typically show greater neural activation for known words than novel words." This could be because the dogs were trying extra hard to understand what their owners were saying.

The results don’t prove that talking to your dog is the best way to get its attention, though—it just means that they may really know what's coming when you say, "Want a cookie?"

Scientists Find Fossil of 150-Million-Year-Old Flesh-Eating Fish—Plus a Few of Its Prey

M. Ebert and T. Nohl
M. Ebert and T. Nohl

A fossil of an unusual piranha-like fish from the Late Jurassic period has been unearthed by scientists in southern Germany, Australian news outlet the ABC reports. Even more remarkable than the fossil’s age—150 million years old—is the fact that the limestone deposit also contains some of the fish’s victims.

Fish with chunks missing from their fins were found near the predator fish, which has been named Piranhamesodon pinnatomus. Aside from the predator’s razor-sharp teeth, though, it doesn’t look like your usual flesh-eating fish. It belonged to an extinct order of bony fish that lived at the time of the dinosaurs, and until now, scientists didn’t realize there was a species of bony fish that tore into its prey in such a way. This makes it the first flesh-eating bony fish on record, long predating the piranha. 

“Fish as we know them, bony fishes, just did not bite flesh of other fishes at that time,” Dr. Martina Kölbl-Ebert, the paleontologist who found the fish with her husband, Martin Ebert, said in a statement. “Sharks have been able to bite out chunks of flesh, but throughout history bony fishes have either fed on invertebrates or largely swallowed their prey whole. Biting chunks of flesh or fins was something that came much later."

Kölbl-Ebert, the director of the Jura Museum in Eichstätt, Germany, says she was stunned to see the bony fish’s sharp teeth, comparing it to “finding a sheep with a snarl like a wolf.” This cunning disguise made the fish a fearful predator, and scientists believe the fish may have “exploited aggressive mimicry” to ambush unsuspecting fish.

The fossil was discovered in 2016 in southern Germany, but the find has only recently been described in the journal Current Biology. It was found at a quarry where other fossils, like those of the Archaeopteryx dinosaur, have been unearthed in the past.

[h/t the ABC]

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