Rats, Mice, and Humans Fail to Ignore Sunk Costs

(p. D6) Suppose that, seeking a fun evening out, you pay $175 for a ticket to a new Broadway musical. Seated in the balcony, you quickly realize that the acting is bad, the sets are ugly and no one, you suspect, will go home humming the melodies.
Do you head out the door at the intermission, or stick it out for the duration?
Studies of human decision-making suggest that most people will stay put, even though money spent in the past logically should have no bearing on the choice.
This “sunk cost fallacy,” as economists call it, is one of many ways that humans allow emotions to affect their choices, sometimes to their own detriment. But the tendency to factor past investments into decision-making is apparently not limited to Homo sapiens.
In a study published on Thursday [July 12, 2018] in the journal Science, investigators at the University of Minnesota reported that mice and rats were just as likely as humans to be influenced by sunk costs.
The more time they invested in waiting for a reward — in the case of the rodents, flavored pellets; in the case of the humans, entertaining videos — the less likely they were to quit the pursuit before the delay ended.
“Whatever is going on in the humans is also going on in the nonhuman animals,” said A. David Redish, a professor of neuroscience at the University of Minnesota and an author of the study.
This cross-species consistency, he and others said, suggested that in some decision-making situations, taking account of how much has already been invested might pay off.

For the full story, see:
Erica Goode. “‘Sunk Cost Fallacy’ Claims More Victims.” The New York Times (Tuesday, July 17, 2018): D6
(Note: bracketed date added.)
(Note: the online version of the story has the date July 12, 2018, and has the title “Mice Don’t Know When to Let It Go, Either.”)

New Tools May Have Allowed Hominins to Leave Africa Far Earlier Than Previously Known

(p. D1) The oldest stone tools outside Africa have been discovered in western China, scientists reported on Wednesday [July 11, 2018]. Made by ancient members of the human lineage, called hominins, the chipped rocks are estimated to be as much as 2.1 million years old.
The find may add a new chapter to the story of hominin evolution, suggesting that some of these species left Africa far earlier than once believed and managed to travel over 8,000 miles east of their evolutionary birthplace.
. . .
(p. D3) The trigger for that migration? Maybe it was figuring out how to make sharp stone tools.
“Suddenly you had a primate that could obtain meat from a carcass, and it opened up a new world for them,” Dr. Dennell said. “That simple technology was enough to get them out of Africa and right across Asia.”

For the full story, see:

Zimmer, Carl. “Ancient Tools Provide New Insight.” The New York Times (Tuesday, July 17, 2018): D1 & D3.

(Note: ellipsis, and bracketed date, added.)
(Note: the online version of the story has the date July 11, 2018, and has the title “Archaeologists in China Discover the Oldest Stone Tools Outside Africa.”)

Government Uses Cruel Painful Snare Traps to Kill Gorgeous Respectful Foxes

(p. A18) BRIGANTINE, N.J. — Red foxes can be found all over New Jersey, wandering out of the woods and poking through garbage at dusk in search of a meal. In many places, they might be overlooked, if not seen as a disease-carrying nuisance. But not in Brigantine, an island community where the fox has become an unofficial ambassador.
Many residents warmly share stories of their encounters, like the fox that would routinely come up to a back door or the time a children’s soccer game had to pause so one could cross the field. A fox makes an appearance on the cover of the city’s tourism guide, as much of an attraction as its golf course and pristine beaches. A real estate company regularly sends its mascot, Briggy the Fox, to community events.
Yet the island is also the seasonal home to piping plovers, a small bird that returns every year to dig its nests on the beach. The bird is an endangered species in New Jersey that state wildlife officials closely watch and fiercely protect, including from foxes, creating a bitter conflict that has caused an uproar as residents protest the trapping and killing of the animals.
Some are challenging the use of snare traps, a contraption that they describe as cruel and painful. The contretemps has also stirred a wider debate: Is it fair to kill one animal for the sake of protecting another?
“It disgusts me,” said Donna Vanzant, who owns a marina. “Why go after these gorgeous animals? Just let nature take its course.”
State lawmakers recently wrote a letter to wildlife officials expressing their “deep concern,” and the City Council passed a resolution condemning the “inhumane and indiscriminate killing of red foxes.” Briggy the Fox attended the meeting and held a sign: “Please stop killing my friends.”
“Everyone on the island cherishes the foxes and does not want them killed,” said Donna Grazioli DeAngelis, a retired teacher who started a petition online, which about 90,000 people have signed. “They have been so respectful, so perfect in every way,” she said of the foxes. “People paint them, photograph them. They haven’t been a nuisance in any way.”
. . .
“It’s an overreach and overreaction,” Philip J. Guenther, Brigantine’s longtime mayor, said of the fox trapping. “It just doesn’t seem to make any sense from a protection standpoint.”

For the full story, see:
Rick Rojas. “To Save One Precious Animal, a Town Must Sacrifice Another.” The New York Times (Monday, May 7, 2018: A18.
(Note: ellipsis added.)
(Note: the online version of the story has the date May 6, 2018, and has the title “Trapping Foxes to Save Plovers Sets Off Showdown at Jersey Shore.” The online version says the print version appeared on May 6 on p. A17 of the New York Edition. My print version, as usual, was the National Edition.)

Ancient Skeletons Harbor a Common Cause of Liver Cancer

(p. A9) Scientists reported on Wednesday [May 9, 2018] that they have recovered DNA from the oldest viruses known to have infected humans — and have succeeded in resurrecting some of them in the laboratory.
The viruses were all strains of hepatitis B. Two teams of researchers independently discovered its DNA in 15 ancient skeletons, the oldest a farmer who lived 7,000 years ago in what is now Germany.
Until now, the oldest viral DNA ever recovered from human remains was just 450 years old.
The research may provide clues to the continuing evolution of hepatitis B, a plague that infects an estimated 257 million people worldwide and contributes to an epidemic of liver cancer.
. . .
Chronic infections can lead to liver cancer. Each year, the World Health Organization estimates, hepatitis B kills 887,000 people. Researchers have long wondered how it became a worldwide menace.
. . .
. . . the skeletons in which the Cambridge geneticists found hepatitis range from 820 to 4,500 years old. The research, published in the journal Nature, demonstrates that hepatitis B existed across Europe and Asia as early as the Bronze Age.
. . .
Johannes Krause and his colleagues examined DNA extracted from the teeth of 53 ancient people in what is now Germany. Three of them were infected with hepatitis B, it turned out: one who lived about 1,000 years ago, a second person who lived 5,300 years ago and a third who lived 7,000 years ago.
. . .
Dr. Krause and his colleagues found that their Stone Age viruses were most closely related to strains of hepatitis B found today only in chimpanzees and gorillas.
He speculated that the virus jumped from apes to humans early in the history of our species in Africa. “It’s more likely this is really an old pathogen in humans for the last hundred thousand years or more,” he said.

For the full story, see:
Zimmer, Carl. “In Ancient Skeletons, Scientists Discover a Modern Foe: Hepatitis B.” The New York Times (Thursday, May 10, 2018): A9.
(Note: ellipses, and bracketed date, added.)
(Note: the online version of the story has the date MAY 9, 2018. The print version cited above is the National Edition.)

The paper by the Cambridge geneticists, mentioned above, is:
Mühlemann, Barbara, Terry C. Jones, Peter de Barros Damgaard, Morten E. Allentoft, Irina Shevnina, Andrey Logvin, Emma Usmanova, Irina P. Panyushkina, Bazartseren Boldgiv, Tsevel Bazartseren, Kadicha Tashbaeva, Victor Merz, Nina Lau, Václav Smrčka, Dmitry Voyakin, Egor Kitov, Andrey Epimakhov, Dalia Pokutta, Magdolna Vicze, T. Douglas Price, Vyacheslav Moiseyev, Anders J. Hansen, Ludovic Orlando, Simon Rasmussen, Martin Sikora, Lasse Vinner, Albert D. M. E. Osterhaus, Derek J. Smith, Dieter Glebe, Ron A. M. Fouchier, Christian Drosten, Karl-Göran Sjögren, Kristian Kristiansen, and Eske Willerslev. “Ancient Hepatitis B Viruses from the Bronze Age to the Medieval Period.” Nature 557, no. 7705 (May 9, 2018): 418-23.

The paper co-authored by Krause, and mentioned above, is:
Krause-Kyora, Ben, Julian Susat, Felix M. Key, Denise Kühnert, Esther Bosse, Alexander Immel, Christoph Rinne, Sabin-Christin Kornell, Diego Yepes, Sören Franzenburg, Henrike O. Heyne, Thomas Meier, Sandra Lösch, Harald Meller, Susanne Friederich, Nicole Nicklisch, Kurt W. Alt, Stefan Schreiber, Andreas Tholey, Alexander Herbig, Almut Nebel, and Johannes Krause. “Neolithic and Medieval Virus Genomes Reveal Complex Evolution of Hepatitis B.” eLife 7 (2018): e36666.

Human Ancestors May Have Had Capacity for Symbolic Thought 600,000 Years Ago

(p. D1) On Thursday [February 22, 2018], a team of researchers offered compelling evidence that Neanderthals bore one of the chief hallmarks of mental sophistication: they could paint cave art. That talent suggests that Neanderthals could think in symbols and may have achieved other milestones not preserved in the fossil record.
“When you have symbols, then you have language,” said João Zilhão, an archaeologist at the University of Barcelona and co-author of the new study.
. . .
(p. D6) But a second study, which Dr. Zilhão and his colleagues published Thursday [February 22, 2018], in the journal Science Advances, hints that Neanderthals might well have been painting long before 64,000 years ago.
The scientists traveled to a cave on the coast of Spain where Dr. Zilhão had earlier discovered shells that had been drilled with holes and painted with ocher.
. . .
He and his colleagues discovered a layer of flowstone sitting atop the rock where they had found the shell jewelry. That flowstone turned out to be about 115,000 years old.
. . .
The colored, pierced shells themselves are probably not much older than that. Up until about 118,000 years ago, the cave was flooded, thanks to higher sea levels.
That finding provides strong evidence that the shells were made by Neanderthals. They were definitely living in Spain 115,000 years ago, while modern humans would not arrive in Europe for another 70,000 years.
The two new studies don’t just indicate that Neanderthals could make cave art and jewelry. They also establish that Neanderthals were making these things long before modern humans — a blow to the idea that they simply copied their cousins.
The earliest known cave paintings made by modern humans are only about 40,000 years old, while Neanderthal cave art is at least 24,000 years older. The oldest known shell jewelry made by modern humans is about 70,000 years old, but Neanderthals were making it 45,000 years before then.
“These results imply that Neanderthals were not apart from these developments,” said Dr. Zilhão. “For all practical purposes, they were modern humans, too.”
The new studies raise another intriguing possibility, said Clive Finlayson, director of the Gibraltar Museum: that the capacity for symbolic thought was already present 600,000 years ago in the ancestors of both Neanderthals and modern humans.
He agreed with Dr. Zilhão that the new study supports the idea that Neanderthals used language. In addition to the evidence of symbolic thought, researchers have also found that the inner ears of Neanderthals were tuned to the frequencies of speech, much like our own.
“We don’t know how they spoke or what they said,” said Dr. Finlayson. “But they had the ability of speech.”
The cave paintings that Dr. Pike and his colleagues have dated are generally abstract. There’s no evidence so far that Neanderthals painted images of lions and other animals, as modern humans did thousands of years later.
But Dr. Pike doesn’t think a lack of animal imagery marks a mental deficiency in Neanderthals. It could simply reflect a cultural preference.’

For the full story, see:
Zimmer, Carl. “MATTER; The Neanderthal, the Artist.” The New York Times (Tuesday, February 27, 2018): D1 & D6.
(Note: ellipses, and bracketed date, added.)
(Note: the online version of the story has the date FEB. 22, 2018, and has the title “MATTER; Neanderthals, the World’s First Misunderstood Artists.”)

The first article mentioned above and co-authored by Zilhão, is:

Hoffmann, D. L., C. D. Standish, M. García-Diez, P. B. Pettitt, J. A. Milton, J. Zilhão, J. J. Alcolea-González, P. Cantalejo-Duarte, H. Collado, R. de Balbín, M. Lorblanchet, J. Ramos-Muñoz, G. Ch Weniger, and A. W. G. Pike. “U-Th Dating of Carbonate Crusts Reveals Neandertal Origin of Iberian Cave Art.” Science 359, no. 6378 (Feb. 23, 2018): 912-915.

The second article mentioned above and co-authored by Zilhão, is:
Hoffmann, Dirk L., Diego E. Angelucci, Valentín Villaverde, Josefina Zapata, and João Zilhão. “Symbolic Use of Marine Shells and Mineral Pigments by Iberian Neandertals 115,000 Years Ago.” Science Advances 4, no. 2 (Feb. 22, 2018): 1-6.

Proof of Concept for Regenerating Limbs and Internal Organs

(p. D3) Scientists have decoded the genome of the axolotl, the Mexican amphibian with a Mona Lisa smile. It has 32 billion base pairs, which makes it ten times the size of the human genome, and the largest genome ever sequenced.
The axolotl, endangered in the wild, has been bred in laboratories and studied for more than 150 years. It has the remarkable capacity to regrow amputated limbs complete with bones, muscles and nerves; to heal wounds without producing scar tissue; and even to regenerate damaged internal organs.
This salamander can heal a crushed spinal cord and have it function just like it did before it was damaged. This ability, which exists to such an extent in no other animal, makes its genes of considerable interest.
. . .
The researchers have identified some of the genes involved in regeneration, and some genes that exist only in the axolotl, but there is much work still to be done.

For the full story, see:
NICHOLAS BAKALAR. “TAKE A NUMBER; 32 Billion.” The New York Times (Tuesday, February 6, 2018): D3.
(Note: ellipsis added.)
(Note: the online version of the story has the date FEB. 1, 2018, and has the title “TAKE A NUMBER; The Smiling Axolotl Hides a Secret: A Giant Genome.”)

Environment Can Affect Which Genes Are Activated

(p. D5) In September 1944, trains in the Netherlands ground to a halt. Dutch railway workers were hoping that a strike could stop the transport of Nazi troops, helping the advancing Allied forces.
But the Allied campaign failed, and the Nazis punished the Netherlands by blocking food supplies, plunging much of the country into famine. By the time the Netherlands was liberated in May 1945, more than 20,000 people had died of starvation.
The Dutch Hunger Winter has proved unique in unexpected ways. Because it started and ended so abruptly, it has served as an unplanned experiment in human health. Pregnant women, it turns out, were uniquely vulnerable, and the children they gave birth to have been influenced by famine throughout their lives.
When they became adults, they ended up a few pounds heavier than average. In middle age, they had higher levels of triglycerides and LDL cholesterol. They also experienced higher rates of such conditions as obesity, diabetes and schizophrenia.
. . .
“How on earth can your body remember the environment it was exposed to in the womb — and remember that decades later?” wondered Bas Heijmans, a geneticist at Leiden University Medical Center in the Netherlands.
Dr. Heijmans, Dr. Lumey and their colleagues published a possible answer, or part of one, on Wednesday in the journal Science Advances. Their study suggests that the Dutch Hunger Winter silenced certain genes in unborn children — and that they’ve stayed quiet ever since.
While all cells in a person’s body share the same genes, different ones are active or silent in different cells. That program largely is locked in place before birth.
But scientists have learned that later experiences — say, exposure to a virus — can cause cells to quiet a gene or boost its activity, sometimes permanently.
The study of this long-term gene control is called epigenetics. Researchers have identified molecules that cells use to program DNA, but how those tools work isn’t entirely clear. One of the best studied is a molecular cap called a methyl group.
At millions of spots across our DNA, genes may carry a methyl group. They seem to silence genes — at least, researchers have found that silenced genes often have a collection of methyl groups lurking nearby.

For the full story, see:
Zimmer, Carl. “Dutch Genes Still Bear Scars of a Famine.” The New York Times (Tuesday, February 6, 2018): D5.
(Note: ellipsis added.)
(Note: the online version of the story has the date JAN. 31, 2018, and has the title “MATTER; The Famine Ended 70 Years Ago, but Dutch Genes Still Bear Scars.”)