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Posted by Kristen French

https://nautil.us/the-silver-lining-in-disappointment-1255173/

https://nautil.us/?p=1255173

Disappointment stings. But this feeling may be more useful than you might think. It seems to help mice change their behavior so that they can avoid similar outcomes in the future, a skill essential to survival for many living things.

Scientists from the Okinawa Institute of Science and Technology (OIST) Graduate University have found that disappointment actually triggers specific changes in the brains of mice that predict adaptive behavior. The findings, which were published in the journal Nature Communications, could help scientists understand a variety of diseases and disorders, from addiction to obsessive compulsive disorder to Parkinson’s disease.

“The brain mechanisms behind changing behaviors have remained elusive, because adapting to a given scenario is very neurologically complex,” said co-author Jeffery Wickens, head of the Neurobiology Research Unit at OIST, in a statement. “It requires interconnected activity across multiple areas of the brain.”

Read more: “Where Is My Mind?”

Wickens and his colleagues trained mice to navigate a virtual maze, meting out a sugary reward when the rodents were successful. They then switched the route, so the mice lost the sweet treat. Using an advanced imaging technique known as two-photon microscopy, they monitored the release of neurotransmitters in the mouse brains in real time as they navigated the maze.

When the goodie the mice had come to expect suddenly went poof, the scientists observed acetylcholine flooding the striatum, a part of the brain associated with movement and reward. The greater the release of neurotransmitter, the more likely the mice were to change their behavior, trying out new routes through the maze. This wasn’t the case, however, during the training phase when they made a wrong choice—only after they had learned to expect the sugary treat.

To confirm their findings, the researchers then turned off the acetylcholine source in the mice—by delivering a specific receptor to their brains using a virus and then activating it—and tried the experiment again. Without the deluge of acetylcholine saturating their brains, the mice were far less likely to hunt for alternative ways to solve the maze when the game changed.

“Our results demonstrated the importance of acetylcholine in breaking habits and enabling new choices to be made,” said co-author Gideon Sarpong, a neuroscientist at OIST.

Previous work had already shown that brain cells that release acetylcholine were involved in behavioral flexibility, but exactly how this worked was unclear. The findings could help scientists better understand the specific roles the neurotransmitter plays in certain neurological disorders.

Maybe this knowledge could even help lessen the bitter sting of disappointments, making feelings of defeat just a little sweeter.

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Lead image: Simple Line / Shutterstock

https://nautil.us/the-silver-lining-in-disappointment-1255173/

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Posted by Molly Glick

https://nautil.us/we-overestimate-the-prevalence-of-online-trolls-1255158/

https://nautil.us/?p=1255158

Social media often feels like a minefield—dodging spiteful and incendiary posts when you’re simply trying to, say, scroll through cute cat photos or seek out Reddit advice on vacuum cleaners.

Fortunately, the internet isn’t necessarily brimming with trolls. People actually tend to vastly overestimate their prevalence, according to online survey results recently published in PNAS Nexus.

Stanford University researchers asked more than 1,000 adults in the United States about their perceptions of the social media trolls behind “severely toxic” comments, which were defined as “hateful, aggressive, and disrespectful” posts that could encourage people to exit an online discussion. The study volunteers were recruited strategically so that the participant pool mirrored proportions of certain demographics, including gender and race, reported in the 2020 U.S. census.

Read more: “Why Your Brain Hates Other People”

Participants estimated how many Reddit users post severely toxic comments—on average, people guessed that number to be about 43 percent. In reality, this figure is closer to around 3 percent, a study presented at the 2023 Association for Computing Machinery Web Conference found. Survey respondents also speculated on the share of Facebook users that circulate fake news, proposing 47 percent on average. But the reality is around 8.5 percent, according to a 2019 Science Advances paper.

Meanwhile, survey respondents were nearly right on the money when guessing the portion of all Reddit postings that are churned out by trolls. They proposed on average that around 38 percent of all Reddit comments—toxic or not—come from these mischievous users, when the reality is closer to around a third, or more than 559 million comments over the 2023 study’s year-and-a-half duration.

The research team also shared accurate data on toxic social media users with some participants, and they reported feeling more positive and more likely to believe that “the character of their fellow U.S. citizens was in less moral decline” than the participants who weren’t given the true information. This group was also more likely to recognize that most people don’t want harmful content to go viral on social media.

“This particular, widely held misperception about social media toxicity can have serious consequences, leaving participants feeling negatively, with higher pessimism about the moral state of their fellow citizens, and with more pluralistic ignorance about how much others desire harmful online content,” the authors wrote.

But this potentially perilous mismatch can be fixed, they noted, by “teaching people that social media can overrepresent the views of vocal accounts that post disproportionately often.”

So don’t let your conspiratorial uncle, or any other troll, cloud your conception of your favorite platforms—and humanity more broadly.

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Lead image: eamesBot / Shutterstock

https://nautil.us/we-overestimate-the-prevalence-of-online-trolls-1255158/

https://nautil.us/?p=1255158

Posted by Devin Reese

https://nautil.us/these-butterflies-change-visual-systems-with-seasons-1255084/

https://nautil.us/?p=1255084

Animals are known to change seasonally with their environments. For example, an Arctic fox that sports a snow-white coat in winter sheds to wear a brown-gray summer coat. These changes are triggered by daylight cues that alter the action of foxes’ pigment-producing genes.

While operating on a different time scale, some butterflies also undergo seasonal changes in their coloration. And a recent study in Functional Ecology shows that color changes are just the tip of the iceberg—in at least one butterfly species, they’re accompanied by shifts in behavior and visual perception.

Researchers from the University of Arkansas and Cornell University studied seasonal changes in buckeye butterflies (Junonia coenia) from Arkansas tallgrass prairies. Because these butterflies live for just a couple of weeks as adults, the changes occur across generations. Buckeyes hatching in summer sport notably lighter-color wings than butterflies hatching in fall. The summer individuals were also known to have higher activity levels and to disperse further than the fall-hatched ones.

Read more: “Do Butterflies Challenge the Meaning of Species?”

From May to November across three years, the scientists assessed buckeye butterfly coloration, wing pattern, behavior, and activity level. From butterfly heads collected once per month, tissue was removed and sampled for RNA (to determine expression of genes). The results showed differential expression of several genes across seasons. As days got shorter and cooler in September, buckeyes emerged with darker wings and spent more time basking in the sun. Those observable changes were accompanied by shifts in gene expression related to eye pigmentation, circadian rhythms, and temperature stress. 

While it’s too early to specify how those genetic shifts manifest in butterfly perceptions, it’s fair to say that there’s more going on seasonally than what meets the eye. “Not only are common buckeye butterflies interacting with their world differently depending on the time of year, but they probably see the world differently at these times of year, too,” University of Arkansas biologist and co-author Grace Hirzel said in a statement.

Whether or not other animals experience seasonal sensory changes in tandem with changes to their bodies and physiology remains to be determined. But such sensory shifts may explain observed changes in behavior. “Changes in sensory system development like we found in the buckeye may be a common strategy used by many animals to survive shifting seasonal conditions,” added Hirzel.

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Lead image: Dr. Thomas G. Barnes, U.S. Fish and Wildlife Service / Wikimedia Commons

https://nautil.us/these-butterflies-change-visual-systems-with-seasons-1255084/

https://nautil.us/?p=1255084