この性格特性が夢をより奇妙にする、科学者が発見

imageWelcome back to the Abstract! These are the stories this week that dared to dream, slinked through the city, mourned their mothers, and visited ancient graveyards.

First, scientists studied thousands of dream reports and discovered that world events—like the COVID-19 pandemic—can manifest in our vespertine visions. Then: the science of urban snake rescues, the lonely lives of orphaned dolphins, and scientists fiddle with Rome’s ancient DNA.

As always, for more of my work, check out my book First Contact: The Story of Our Obsession with Aliens or subscribe to my personal newsletter the BeX Files.

The dream of understanding dreams

Elce, Valentina et al. “Individual traits and experiences predict the content of dreams.” Communications Psychology.

Why do we dream? It’s a question that has kept people up at night for thousands of years. Now, scientists have taken a new crack at the mystery by collecting and analyzing more than 3,700 reports from 207 participants who described both their dreams and waking experiences between 2020 to 2024, as well as 80 participants who reported their dreams during the onset of the COVID-19 pandemic from April to May 2020.

The results revealed possible links between personality traits and dream experiences, and suggested that dreams are influenced by external events such as the pandemic.

“During lockdown, dreams showed increased references to limitations and heightened emotional intensity, effects that gradually normalized over the following years,” said researchers led by Valentina Elce of IMT School for Advanced Studies Lucca. “These findings demonstrate that stable individual traits and incidental experiences jointly shape dream semantics.”

For the main dataset, Elce and her colleagues recruited 207 Italian adults ranging from 18 to 70 years old who were assessed for their psychological and cognitive traits, demographics, and sleep patterns. These participants recorded recollections of their dreams as soon as they woke up using a scale of descriptive elements, such as bizarreness, vividness, valence (emotional tone), and the level of agency they had over events in the dream. This sample of dreamers was also prompted to record their waking experiences throughout the day.

imageFigure 1 of the study illustrates descriptive statistics of report content across vigilance states (i.e., wakefulness and dream). Image: Elce, Valentina et al. The team used natural language processing models to quantitatively analyze the semantic structure of the dream reports and correlations between individual traits and dream experiences. For example, people who let their mind wander in their waking hours reported having more bizarre dreams.

“Our findings indicate that dream bizarreness is associated with a higher tendency of the individuals to mind-wander, which also drives frequent shifts in narrative settings,” the team said. “This is in line with accounts suggesting that dreaming and mind-wandering may share a common neural and cognitive foundation.”

The lockdown group, meanwhile, was composed of 60 women and 20 men who recorded their dreams in diaries during spring 2020. By comparing the two samples, the researchers suggest that “external emotionally salient events, in this case the COVID-19 pandemic, might affect dream experiences and how such effects develop over long time spans,” according to the study.

“Notably, themes concerning healthcare, which were heavily represented in daily life during the pandemic, showed no significant changes,” the researchers said. “However, in a continuous line with what was happening in the daylight world, the actions of the individuals while they were dreaming were described as limited by physical or metaphorical constraints and the recalled emotional states carried a stronger intensity.”

Godspeed to the oneirologists—the term for scientists who study dreams—for finding new ways to probe these ephemeral experiences that constantly elude explanation.

In other news…

Hey, I’m slithering here!

Visvanathan, Avinash C. et al. “Urban snake ecology revealed through the lens of decadal data on snake rescues in a megacity.” Global Ecology and Conservation.

In cities with urban snake populations, such as Hyderabad in India, millions of people live alongside venomous snakes—including deadly Indian cobras and Russell’s vipers—that have been displaced by rapid habitat loss.

To discourage people from just killing these cosmopolitan cobras, an organization called the Friends of Snakes Society performs “snake rescues” with trained handlers who remove snakes and transport them to safer locations. By analyzing 55,467 snake rescue records in Hyderabad from 2013 to 2022, a team found that snake rescues rose nearly 17 percent over the decade, and that about 54 percent (n = 30,189) of rescues involved venomous snakes.

imageVenomous Indian cobras were the most common snakes to be rescued, making up 49 percent of all cases (27,132 snakes). Image: Pavan Kumar N“Snakes have either become locally extinct or have adapted to the city as their habitat, resulting in intensified human–wildlife interactions in Hyderabad and its neighboring areas,” said researchers led by Avinash Visvanathan of the Friends of Snakes Society. “The dataset demonstrates that standardized snake rescue operations not only mitigate immediate risks but also generate valuable ecological information.”

As always, The Simpsons already did it with the 1993 episode “Whacking Day,” though in that case, a mass snake rescue was made possible by the dulcet tones of Barry White rather than a helpline. Perhaps the efficacy of baritone vocals in urban snake management could offer a future avenue of study.

Orphans of the sea

Cristina Vicente-Sánchez et al. “Two Cases of Early Orphan Survival in Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) From the Adelaide Dolphin Sanctuary, South Australia.” Marine Mammal Science.

Dolphins, like humans, invest a lot of maternal care into their young, typically nursing calves for two to three years. But scientists now discovered that months-old orphaned calves can survive the deaths of their mothers—though they are negatively impacted by their losses.

Ali, an Indo-Pacific bottlenose dolphin born in February 2011, suddenly lost her mother Millie in October that same year; Rocket, a member of the same species born in February 2022, was orphaned at seven months old after her mother Ripple disappeared.

imageAli photographed shortly before becoming an orphan in 2011 in (a) and (b) and with her newborn calf in March 2025. Images: Barbara Saberton (a) and Cristina Vicente Sanchez (b).Ali is probably still alive and birthed her own calf in 2025, though it sadly died of blunt force trauma at a few weeks old, possibly due to infanticide or a boat strike. Rocket endured for three years, and was sometimes spotted with a mother-calf pair that may have cared for her, before she was killed by a boat strike last year. Both Ali and Rocket displayed maladaptive behavior, especially getting too close to boats.

The study “provides rare empirical evidence that young-of-year calves can persist without maternal care,” said researchers led by Cristina Vicente-Sánchez of Flinders University.

It’s a bittersweet finding, demonstrating that when young calves are forced to sink or swim, some can make it—but they may bear lifelong signs of bereavement.

The fall of Rome, according to DNA

Blöcher, Jens,  Vallini, Leonardo et al. “Demography and life histories across the Roman frontier in Germany 400–700 ce.” Nature.

Oceans of ink have been spilled on the rise and fall of the Roman empire, but scientists have now read the story that is written in the genomes of people who lived in the aftermath.

A new study analyzed ancient DNA from 258 individuals found at grave sites in southern Germany who died between the years 400 and 700. These reconstructed lineages “reveal a major demographic shift coinciding with the late fifth century collapse of Roman state structures, when a founding population of northern European ancestry mixed with genetically diverse Roman provincial groups” said researchers co-led by Jens Blöcher and Leonardo Vallini of Johannes Gutenberg University Mainz.

These intermarriages eventually formed ”a population resembling modern Central Europeans by the early seventh century,” and reflected the rise of “Christian ideals such as lifelong monogamy, with minimal divorce or remarriage after widowhood” and “strict incest avoidance,” according to the study.

While this time of transition “has traditionally been framed as a conflict between northern ‘barbarians’ and a Roman Empire in decline, newer studies reveal a multifaceted transformation,” the team added.

Rome wasn’t built in a day, so the saying goes, and its flamboyant collapse is arguably still in motion, inspiring new interpretations and never-ending material for history podcasters.

Thanks for reading! See you next week.