Infants Can See Image Differences That Adults Cannot, Study Finds


Babies may be able to see image details that are invisible or imperceptible to adults. According to a recent study [PDF] from Japanese scientists Jiale Yang, So Kanazawa, Masami K. Yamaguchi, and Isamu Motoyoshi, three- and four-month-old infants may view certain images differently because they lack perceptual constancy. That means they can see small image differences that are invisible to adults because of changes in lighting conditions.

For example, when adults see the same objects in different lighting, their brains automatically adjust to those lighting conditions. If your friend steps in front of a blue spotlight, they might appear blue, but you still recognize them. That’s perceptual constancy in action: Your brain recognizes that, though your friend is bathed in blue light, they aren’t suddenly a totally different blue person. Young babies who haven’t yet developed perceptual constancy, meanwhile, are able to see subtle images differences that adults ignore, but may be unable to recognize the same objects in different light.

In the study, 42 babies between three and eight months old looked at images rendered from 3D objects like snails and teapots. Since the babies were pre-verbal, scientists tracked their eye movements to determine how they interacted with the images. According to Scientific American, previous studies have shown that infants spend more time looking at new objects than those they’ve seen before, so the scientists in the study measured infant recognition of different objects by recording how long they looked at each image. They found that infants up to four months old recognized image differences caused by changes in illumination that weren’t visible to adult viewers. At five months old, however, the infants lost that ability, and by seven or eight months, began to develop perceptual constancy.

In the above image, for example, adults generally see snails A and B as the most similar because of their glossy finish. In reality, B and C are most similar with regards to pixel intensity—a characteristic that three- and four-month-old infants recognized.

According to the scientists, “These findings support the notion that acquiring perceptual constancy leads to a loss of sensitivity to variant information, which is negligible for constant surface material perception.”

That is, as we develop, we lose the ability to see certain information, but that loss makes it easier for us to understand the world around us. As Scientific American explains, “The loss of sensitivity to variant information that we all experienced as babies created an unbreachable gap between us and the physical world. At the same time, it served to tune our perception to our environment, allowing us to navigate it efficiently and successfully.”

[h/t: Scientific American]

Charles Dickens Museum Highlights the Author's Contributions to Science and Medicine

Charles Dickens is celebrated for his verbose prose and memorable opening lines, but lesser known are his contributions to science—particularly the field of medicine.

A new exhibition at London’s Charles Dickens Museum—titled "Charles Dickens: Man of Science"—is showcasing the English author’s scientific side. In several instances, the writer's detailed descriptions of medical conditions predated and sometimes even inspired the discovery of several diseases, The Guardian reports.

In his novel Dombey and Son, the character of Mrs. Skewton was paralyzed on her right side and unable to speak. Dickens was the first person to document this inexplicable condition, and a scientist later discovered that one side of the brain was largely responsible for speech production. "Fat boy" Joe, a character in The Pickwick Papers who snored loudly while sleeping, later lent his namesake to Pickwickian Syndrome, otherwise known as obesity hypoventilation syndrome.

A figurine of Fat Boy Joe
Courtesy of the Charles Dickens Museum

Dickens also wrote eloquently about the symptoms of tuberculosis and dyslexia, and some of his passages were used to teach diagnosis to students of medicine.

“Dickens is an unbelievably acute observer of human behaviors,” museum curator Frankie Kubicki told The Guardian. “He captures these behaviors so perfectly that his descriptions can be used to build relationships between symptoms and disease.”

Dickens was also chummy with some of the leading scientists of his day, including Michael Faraday, Charles Darwin, and chemist Jane Marcet, and the exhibition showcases some of the writer's correspondence with these notable figures. Beyond medicine, Dickens also contributed to the fields of chemistry, geology, and environmental science.

Less scientifically sound was the author’s affinity for mesmerism, a form of hypnotism introduced in the 1770s as a method of controlling “animal magnetism,” a magnetic fluid which proponents of the practice believed flowed through all people. Dickens studied the methods of mesmerism and was so convinced by his powers that he later wrote, “I have the perfect conviction that I could magnetize a frying-pan.” A playbill of Animal Magnetism, an 1857 production that Dickens starred in, is also part of the exhibit.

A play script from Animal Magnetism
Courtesy of the Charles Dickens Museum

Located at 48-49 Doughty Street in London, the exhibition will be on display until November 11, 2018.

[h/t The Guardian]

Feeling Down? Lifting Weights Can Lift Your Mood, Too

There’s plenty of research that suggests that exercise can be an effective treatment for depression. In some cases of depression, in fact—particularly less-severe ones—scientists have found that exercise can be as effective as antidepressants, which don’t work for everyone and can come with some annoying side effects. Previous studies have largely concentrated on aerobic exercise, like running, but new research shows that weight lifting can be a useful depression treatment, too.

The study in JAMA Psychiatry, led by sports scientists at the University of Limerick in Ireland, examined the results of 33 previous clinical trials that analyzed a total of 1877 participants. It found that resistance training—lifting weights, using resistance bands, doing push ups, and any other exercises targeted at strengthening muscles rather than increasing heart rate—significantly reduced symptoms of depression.

This held true regardless of how healthy people were overall, how much of the exercises they were assigned to do, or how much stronger they got as a result. While the effect wasn’t as strong in blinded trials—where the assessors don’t know who is in the control group and who isn’t, as is the case in higher-quality studies—it was still notable. According to first author Brett Gordon, these trials showed a medium effect, while others showed a large effect, but both were statistically significant.

The studies in the paper all looked at the effects of these training regimes on people with mild to moderate depression, and the results might not translate to people with severe depression. Unfortunately, many of the studies analyzed didn’t include information on whether or not the patients were taking antidepressants, so the researchers weren’t able to determine what role medications might play in this. However, Gordon tells Mental Floss in an email that “the available evidence supports that [resistance training] may be an effective alternative and/or adjuvant therapy for depressive symptoms that could be prescribed on its own and/or in conjunction with other depression treatments,” like therapy or medication.

There haven’t been a lot of studies yet comparing whether aerobic exercise or resistance training might be better at alleviating depressive symptoms, and future research might tackle that question. Even if one does turn out to be better than the other, though, it seems that just getting to the gym can make a big difference.


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