HEALTH

Babies’ random choices become their preferences

WHEN a baby reaches for one stuffed animal in a room filled with others just like it, that seemingly random choice is very bad news for those unpicked toys: the baby has likely just decided she doesn’t like what she didn’t choose.
Though researchers have long known that adults build unconscious biases over a lifetime of making choices between things that are essentially the same, the new Johns Hopkins University finding that even babies engage in this phenomenon demonstrates that this way of justifying choice is intuitive and somehow fundamental to the human experience.
“The act of making a choice changes how we feel about our options,” said co-author Alex Silver, a former Johns Hopkins undergraduate who’s now a graduate student in cognitive psychology at the University of Pittsburgh. “Even infants who are really just at the start of making choices for themselves have this bias.”
The findings are published today in the journal Psychological Science.
People assume they choose things that they like. But research suggests that’s sometimes backwards: We like things because we choose them. And, we dislike things that we don’t choose.
“I chose this, so I must like it. I didn’t choose this other thing, so it must not be so good. Adults make these inferences unconsciously,” said co-author Lisa Feigenson, a Johns Hopkins cognitive scientist specializing in child development. “We justify our choice after the fact.”
This makes sense for adults in a consumer culture who must make arbitrary choices every day, between everything from toothpaste brands to makes of cars to styles of jeans. The question, for Feigenson and Silver, was when exactly people start doing this. So they turned to babies, who don’t get many choices so, as Feigenson puts it, are “a perfect window into the origin of this tendency.”
The team brought 10- to 20-month-old babies into the lab and gave them a choice of objects to play with: two equally bright and colorful soft blocks.
They set each block far apart, so the babies had to crawl to one or the other — a random choice.
After the baby chose one of the toys, the researchers took it away and came back with a new option. The babies could then pick from the toy they didn’t play with the first time, or a brand new toy.
“The babies reliably chose to play with the new object rather than the one they had previously not chosen, as if they were saying, ‘Hmm, I didn’t choose that object last time, I guess I didn’t like it very much,’ “ Feigenson said.
“That is the core phenomenon. Adults will like less the thing they didn’t choose, even if they had no real preference in the first place. And babies, just the same, dis-prefer the unchosen object.”
In follow-up experiments, when the researchers instead chose which toy the baby would play with, the phenomenon disappeared entirely. If you take the element of choice away, Feigenson said, the phenomenon goes away.
“They are really not choosing based on novelty or intrinsic preference,” Silver said. “I think it’s really surprising. We wouldn’t expect infants to be making such methodical choices.”
To continue studying the evolution of choice in babies, the lab will next look at the idea of “choice overload.” For adults, choice is good, but too many choices can be a problem, so the lab will try to determine if that is also true for babies. –Science Daily

Neanderthal hand in severe Covid-19

Genetic variants that leave their carrier more susceptible to severe COVID-19 are inherited from Neanderthals, a new study finds.

SINCE first appearing in late 2019, the novel virus, Sars-CoV-2, has had a range of impacts on those it infects. Some people become severely ill with Covid-19, the disease caused by the virus, and require hospitalisation, whereas others have mild symptoms or are even asymptomatic.
There are several factors that influence a person’s susceptibility to having a severe reaction, such as their age and the existence of other medical conditions. But one’s genetics also plays a role, and, over the last few months, research by the Covid-19 Host Genetics Initiative has shown that genetic variants in one region on chromosome 3 impose a larger risk that their carriers will develop a severe form of the disease.
Now, a new study, published in Nature, has revealed that this genetic region is almost identical to that of a 50,000-year old Neanderthal from southern Europe. Further analysis has shown that, through interbreeding, the variants came over to the ancestors of modern humans about 60,000 years ago.
“It is striking that the genetic heritage from Neanderthals has such tragic consequences during the current pandemic,” said Prof Svante Pääbo, who leads the Human Evolutionary Genomics Unit at the Okinawa Institute of Science and Technology Graduate University (OIST).
Is severe Covid-19 written in our genes?
Chromosomes are tiny structures that are found in the nucleus of cells and carry an organism’s genetic material. They come in pairs with one chromosome in each pair inherited from each parent. Humans have 23 of these pairs. Thus, 46 chromosomes carry the entirety of our DNA — millions upon millions of base pairs. And although the vast majority are the same between people, mutations do occur, and variations persist, at the DNA level.
The research by the Covid-19 Host Genetics Initiative looked at over 3,000 people including both people who were hospitalised with severe Covid-19 and people who were infected by the virus but were not hospitalised. It identified a region on chromosome 3 that influences whether a person infected with the virus will become severely ill and needs to be hospitalised.
The identified genetic region is very long, spanning 49.4 thousand base pairs, and the variants that impose a higher risk to severe Covid-19 are strongly linked — if a person has one of the variants then they’re very likely to have all thirteen of them. Variants like these have previously been found to come from Neanderthals or Denisovans so Professor Pääbo, in collaboration with Prof Hugo Zeberg, first author of the paper and a researcher at the Max Planck Institute for Evolutionary Anthropology and Karolinska Institutet, decided to investigate whether this was the case.
They found that a Neanderthal from southern Europe carried an almost identical genetic region whereas two Neanderthals from southern Siberia and a Denisovan did not.
Next, they questioned whether the variants had come over from Neanderthals or had been inherited by both Neanderthals and present-day people through a common ancestor.
If the variants had come from interbreeding between the two groups of people, then this would have occurred as recently as 50,000 years ago. Whereas, if the variants had come from the last common ancestor, they would have been around in modern humans for about 550,000 years. But random genetic mutations, and recombination between chromosomes, would have also occurred during this time and because the variants between the Neanderthal from southern Europe and present-day people are so similar over such a long stretch of DNA, the researchers showed that it was much more likely that they came from interbreeding.
Profs Pääbo and Zeberg concluded that Neanderthals related to the one from southern Europe contributed this DNA region to present-day people around 60,000 years ago when the two groups met.
Neanderthal variants pose up to three times the risk
Prof Zeberg explained that those who carry these Neanderthal variants have up to three times the risk of requiring mechanical ventilation.
“Obviously, factors such as your age and other diseases you may have also affect how severely you are affected by the virus. But among genetic factors, this is the strongest one.”
The researchers also found that there are major differences in how common these variants are in different parts of the world. In South Asia about 50 per cent of the population carry them. However, in East Asia they are almost absent.
It is not yet known why the Neanderthal gene region is associated with increased risk of becoming severely ill. “This is something that we and others are now investigating as quickly as possible,” said Prof Pääbo. – Science Daily.

Young more likely to say no to alcohol

CALL them Generation Dry. More college-age Americans are choosing not to drink alcohol than they did nearly two decades ago, according to a new study.
Between 2002 and 2018, the number of adults age 18 to 22 in the United States who abstained from drinking alcohol increased from 20 per cent to 28 per cent for those in college. For those not in school, the percentage was 30 per cent, up from 24 per cebnt in 2002.
Alcohol abuse among both groups decreased by roughly half.
“We’re encouraged by the significant decreases in alcohol use disorder — for both college and non-college students,” said Sean Esteban McCabe, director of the Center for the Study of Drugs, Alcohol, Smoking and Health at the University of Michigan School of Nursing and lead author of the study that published Monday in the journal Jama Pediatrics.
While the study didn’t look at the reasons for the decrease, the authors suggested the changes could be down to the increases in the number of young adults who live with their parents as well as alcohol prevention and intervention efforts that have targeted college students.
It’s not just young Americans who are drinking less. Risky behavior such as binge drinking is much less prevalent in the United Kingdom than it used to be.
Researchers recently found that 29 per cent of 16- to 24-year olds in the UK were non-drinkers in 2015 in the UK, up from 18 per cent in 2005, while rates of binge drinking — defined as drinking twice the recommended daily limits — fell from 27 per cent to 18 per cent.
Misusing several substances
The most alarming trend the study identified was more young adults using or misusing several different substances, as opposed to just marijuana or alcohol.
“Points of concern that deserve more attention are the rise in co-use of alcohol and marijuana, as we know that polysubstance use can have more negative consequences and be more difficult to treat,” said Ty Schepis, a professor of psychology at Texas State University and a co-author of the study.
“For example, from 2015 to 2018, only 2.5 per cent of young adults who abstained from both alcohol and marijuana reported misusing prescription drugs, while 25.1 per cent of co-users misused prescription drugs,” Schepis said.
“That is a tenfold difference with potentially dangerous consequences.”
The study found that marijuana use increased from 27 per cent to 31 per cent among college students from 2002 to 2018 and 26 per cent to 30 per cent among those not in college — but the researchers didn’t find an increase in
The study said US policymakers must “find ways to address the changing landscape of substance use behaviors by providing support to the increasing number of young adults who are abstinent, while also creating interventions to address the increases in marijuana use and co-use of alcohol and marijuana.”
The study examined data collected each year as part of National Survey on Drug Use and Health. The sample included 182,722 adults ages 18 to 22 years.
Although drinking by people under the age of 21 is illegal in the US, people ages 12 to 20 years drink 11 per cent of all alcohol consumed in the United States, according to the CDC. – CNN