Chimpanzees are aping robots and scientists are scratching their heads

A new study reveals that chimpanzees can "catch" yawns from an android robot that imitates human facial expressions.
Researchers found that chimpanzees yawned and lay down in response to yawns made by the android robot, suggesting that observing another individual yawn may act as a cue to rest.
The study involved exposing 14 adult chimpanzees to an android head that simulated facial expressions, including yawns, gaping, and neutral expressions.
Eight of the 14 chimpanzees yawned in response to the android's "yawn" expression, with the highest contagion occurring when the android displayed a fully wide-open mouth.
The findings shed light on primates' susceptibility to contagiously induced behaviours, but the exact biological mechanisms surrounding contagious yawning remain unclear, prompting further research.

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The Guardian

7 hours ago

• The Guardian

Do electric vehicles make people more carsick?

With electric cars skyrocketing in popularity around the world – in 2024, 22% of new car sales worldwide were electric vehicles, compared with 18% in 2023 – a growing body of studies and an increasing number of people have found that they feel more motion sick riding in EVs than in traditional petrol or diesel cars. Anecdotes of feeling sick in the passenger or back seat of electric cars litter social media, as do questions from wary prospective buyers. There is a scientific explanation behind why a person might feel more sick in an EV, though, according to multiple academic studies. 'Greater sickness in EVs can be attributed to a lack of previous experience, as both a driver and as a passenger, where the brain lacks accuracy in estimating the motion forces because it relies on previous experience in other types of cars,' said William Emond, a PhD student researching car sickness at the Université de Technologie de Belfort-Montbéliard in France. Though EVs are becoming more popular, combustion cars still dominate. Riders have a longer history with gas cars and so have had more time to adapt to their specific cues. If a person has spent most of their life driving a combustion engine car, their brain anticipates acceleration after the rev of the engine, a warning that they are about to experience a change in speed. In a battery-powered car, the electric motor makes no such noises. In addition to general unfamiliarity, research has found links between specific features common to electric vehicles and motion sickness. One 2024 study concluded that there were strong correlations between motion sickness severity and the seat vibrations of electric vehicles, while a 2020 study found that the lack of engine sound in an EV might be a major contributing factor to increased feelings of carsickness. 'If we are accustomed to traveling in non-EVs, we are used to understanding the car's motion based on signals such as engine revs, engine vibrations, torque, etc. Yet, traveling in an EV for the first time is a new motion environment for the brain, which needs adaptation,' Emond explains. Additionally, the regenerative braking technology used in EVs – where the motor converts the slowing car's kinetic energy into electricity that then is stored in the battery – results in low-frequency deceleration, meaning that the vehicle slows down gradually and steadily, over a relatively longer period, rather than rapidly or in quick pulses. Such low-frequency deceleration tends to be associated with higher levels of motion sickness. A 2024 study suggested the feature acted as one of the main triggers of motion sickness in electric vehicles. The study's authors wrote: 'Our results confirmed that higher levels of RB [regenerative braking] can induce MS [motion sickness].' Motion sickness is thought to be caused by a mismatch between various sensory signals the brain simultaneously receives about the body's movement. Specifically, it happens when the inner ear, which helps control balance, the eyes, and the body send conflicting information to the brain. 'Better knowledge on self-motion allows us to anticipate motion forces, which is crucial for motion sickness. Yet, when the motion forces as estimated or anticipated by the brain differ from what actually is experienced, then the brain interprets this 'neural mismatch' as a situation of conflict,' Emond said. 'If this conflict persists over time, it may surpass a threshold for triggering autonomic reactions of the body such as symptoms apparent to 'motion sickness'.' Being able to anticipate the movement of a vehicle appears to be integral to the experience of motion sickness, which is why people who are driving a car don't tend to experience symptoms. They know what is coming. The interplay between anticipation of motion and actual motion experienced may be why EVs are associated with worse motion sickness, as these vehicles provide fewer clues regarding upcoming movements. 'When discovering a new motion environment, the brain needs to habituate because there is no knowledge of previous experience in such a context. This is, for example, why almost everyone becomes sick in zero-gravity environments,' Emond says. As EV ownership continues to increase, some researchers are already looking into a solution for the cars' specific type of nausea. Several research papers have suggested that motion sickness in autonomous EVs could be treated by using visual signals, such as interactive screens and ambient lighting, or vibrational cues to allow a passenger's brain to anticipate motion changes, alleviating the lurching feeling in the back of an electric taxi.

Medical News Today

7 hours ago

• Medical News Today

Modified DASH diet may reduce blood pressure in people with type 2 diabetes

Many people with diabetes also have high blood pressure, as well as unique nutritional study found that reducing sodium intake and following a modified version of the DASH diet helped to decrease blood pressure in participants with type 2 main reason for the observed decrease in blood pressure was the decreased sodium is common for people with diabetes to also experience high blood pressure. A study tested how a modified version of the DASH diet that focused on the nutritional needs of people with type 2 diabetes, combined with minimizing sodium intake, affected blood pressure dietary combination lowered systolic blood pressure among participants by around five points and diastolic blood pressure by around two points compared to the comparison diet with more sodium. This result was mainly from the decreased sodium findings were published in JAMA Internal DASH4D diet for blood pressure management The dietary approaches to stop hypertension (DASH) diet is a diet for heart health. Study author Scott J. Pilla, MD, MHS, explained to Medical News Today that 'The DASH diet is a healthy diet that is rich in fruits, vegetables and low-fat dairy products, and is lower in saturated fat and cholesterol.'However, the study notes that the DASH diet doesn't consider the unique dietary needs of people with type 2 diabetes. So, researchers created the 'Dietary Approaches to Stop Hypertension for Diabetes (DASH4D) diet,' which is similar to the DASH diet but considers what adults with type 2 diabetes need. For example, this diet was lower in carbohydrates than the typical DASH diet. Researchers tested how this diet, combined with decreased sodium intake, affected participants' blood randomized clinical trial included 102 adults with type 2 diabetes whose systolic blood pressure was between 120 and 159 mmHg. Participants were designated as having type 2 diabetes if they had a hemoglobin A1C of 6.5% or greater, were taking medications for diabetes treatment, or were ineligible to participate in the study for a number of reasons, including having type 1 diabetes, if their A1C was over 9%, or if they were taking weight loss average age of participants was 66 years. About two-thirds of participants used at least two medications to help lower blood pressure, and a little over half used at least two medications to lower blood 4 different dietsResearchers assigned participants to receive four diets in varying orders, each for five weeks. One was a DASH4D diet with low sodium, and another was the DASH4D diet but with higher sodium intake. The other two were comparison diets: one with lower sodium and one with higher sodium, and these diets were similar to the intake of adults with diabetes living in the United States. The participants were provided with the food for their assigned diets, and aside from allowed beverages, they were not supposed to eat food from other sources outside the did not lose weight throughout the study. Researchers measured systolic blood pressure during the last two weeks of each diet intervention. They kept track of adverse events among participants, such as any very high blood pressure self-reported how well they stuck to their assigned diets, but researchers also did a 24-hour urine excretion test during the fourth or fifth weeks to look at sodium, creatinine, and potassium levels, which also was a way to test how well participants were following diet findings showed that the lowering of blood pressure mostly occurred during the first three weeks of participants following a diet. The researchers found that the DASH4D diet with reduced sodium showed a better overall decrease in blood pressure versus the comparison diet that had higher sodium intake. The average difference in systolic blood pressure between these two groups was 4.6 mmHg, and the average difference in diastolic blood pressure was 2.3 mmHg.'The main finding was that a low-sodium DASH4D diet (compared to a higher sodium typical American diet) caused a statistically and clinically significant reduction in blood pressure. Sodium reduction appeared to contribute more strongly to reducing blood pressure than the DASH4D diet.'— Scott J. Pilla, MDJennifer Wong, MD, a board-certified cardiologist and medical director of Non-Invasive Cardiology at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA, also noted that 'Studies like these remind us of the beneficial impact of a heart-healthy diet, especially a low salt diet designed to modify blood pressure.'Study limitations This research only included a small number of participants and focused on a niche subgroup of individuals, limiting generalizability. The majority of participants were Black, which provided important information about this at-risk group. Two-thirds of the participants were women. However, research in other groups may also be dietary interventions for this study each only lasted five weeks, so long-term follow-up may be helpful with further data, such as following the assigned diet and health history, was self-reported by participants, so inaccuracies are adverse events on the DASH4D diet with low sodium were low, more research into the potential risks may be helpful. Researchers also suggest the need for more research in people with a higher level of risk. The amount that blood pressure was lowered by could have been less in this study for many reasons, such as the high number of participants taking diuretics and the number of participants who experienced changes to their blood pressure medications during the acknowledge that they weren't able to detect the separate impact of the DASH4D diet and decreased sodium intake. Another struggle was the COVID-19 pandemic. The authors explain that this 'interrupted participant feeding at several points.' It was also only a single-site also noted that 'More work is needed on how to make healthy, low sodium diets accessible. Following a healthy diet can be challenging and costly, and we would like to design diets that meet the DASH4D nutrient targets that are more affordable and tailored to different cultures.'Researchers note that it may be hard to decrease sodium intake to only 1,500 mg a day, and future research in this area will be helpful. The authors say this research should include 'implementation research in community settings.'Should I follow a DASH4D diet if I have diabetes?The result suggests that the DASH4D eating plan combined with lower sodium intake helps with blood pressure reduction in people with type 2 diabetes. Researchers note that a five mmHg reduction in systolic blood pressure can decrease the risk of stroke, heart failure, and cardiovascular events. It can also help with kidney noted the following regarding the clinical implications of the study:'Diet change can effectively improve blood pressure in people with diabetes, even those on multiple antihypertensive medications, so clinicians should still focus on diet even in these individuals.''Dietary sodium reduction is an important part of dietary change in people with diabetes to achieve better blood pressure control. Our specific DASH4D diet with lower sodium now has strong evidence for benefiting people with diabetes, so it should be strongly considered as a recommended diet in this population.'— Scott J. Pilla, MDEven though there may be a need for more research, Patrick Kee, MD, PhD, a cardiologist at Vital Heart & Vein, noted the following about the study's results:'The acceptability and adherence to the lower sodium intake (~1500 mg/day) was high among participants, suggesting that with proper guidance and access to prepared meals or education, such dietary targets are feasible in practice. This finding counters a long-standing belief that stringent sodium targets may be unrealistic for patients.'

BBC News

10 hours ago

• BBC News

'Eldest daughter syndrome' to the rebellious youngest sibling: Does your birth order shape your personality?

The question of whether siblings' birth order shapes their personality has puzzled families and psychologists for years. But the evidence isn't as straightforward as you might think. As the eldest daughter of two, I often identify with the traits stereotypically associated with being the oldest sibling: responsible, conscientious, a perfectionist. My mum is an eldest daughter, too, and also shares those traits. My younger sister, on the other hand, is a bit more carefree – even though she and I grew up in the same household with the same parents, and are close, our personalities are quite different. I wondered whether that difference could be due to our birth order – is there any science to the idea that being the oldest, the youngest, or an only child, shapes who we are, and how we navigate the world? A century-long mystery Despite fascinating the scientific community and public for more than 100 years, the question of whether our birth order amongst siblings shapes our personalities is very much still up for debate. Historically, research has produced inconsistent findings. There are several reasons why this is, though to put it simply: it's hard to measure. Rodica Damian, an associate professor in psychology at the University of Houston, Texas, in the US, explains that previous studies have often included small sample sizes. In addition, since personality tests are often self-reported, they may be affected by bias. Recent studies point out that a number of confounding variables can make it hard to investigate if birth order is systematic, meaning that it affects every person in the same way. The total number of siblings may be a factor, for example: one would expect the overall dynamics to be different in a family with two siblings compared to a family with seven siblings. Being the eldest or youngest child in these differently-sized families might be a very different experience, and not directly comparable. Family size and the experience of being a child in any given family may in turn be entangled with many other factors, such as a family's socioeconomic status (wealthier families with higher socioeconomic status tend to have fewer children, for example). And then there is a person's age and gender, which could influence their experience within the family and beyond. Within this context, researchers have not been able to conclude that birth order has any consistent, universal impacts on our personalities. But that doesn't mean birth order is irrelevant. It could play a role within certain families, or cultures. "I think people have a lot of beliefs that are kind of outdated, or that were never well supported in the first place," says Julia Rohrer, a personality researcher at Leipzig University in Germany. "For example, the 'eldest daughter syndrome' thing is a big one – of course, women often still have different roles and are expected to provide more care. And then, first-borns are expected to take care of younger siblings," she says. "For some women, this might perfectly match their experience but for others it doesn't because every family is different." In other words, not every eldest daughter will be responsible and caring – but for some, the idea of an "eldest daughter syndrome" may ring true because they really did grow up having to look after their younger siblings and feel that this experience shaped them. Rohrer and her colleagues have found that birth order "does not have a lasting effect on broad personality traits" after examining three large datasets from surveys in the UK, US and Germany, each comprising data from several thousand people. However, the study did confirm previous findings on the impact of birth order on one specific trait: intelligence. Intelligence is a complex phenomenon and the study only measures it in the form of performance in intelligence tests, and self-reported intellect. "We confirmed the effect that firstborns score higher on objectively measured intelligence and additionally found a similar effect on self-reported intellect," Rohrer and her colleagues wrote in the study. Previous research had documented that performances in intelligence tests "decline slightly from firstborns to later-borns". As for birth order and other personality traits, Rohrer says reflecting on one's experience can still be meaningful, even if there is no universal pattern: "It does provide a label where you can find other people who grew up in a similar situation, and you can exchange experiences and so on," she says of terms such as "eldest daughter syndrome". There is nothing wrong with framing your experience that way, "as long as you don't assume that this experience is universal," she says. Damian echoes this: "While we don't find differences in personality that are systematic, that doesn't mean that there aren't social processes within each family or within each culture that can lead to different outcomes based on birth order." For example, the UK has a historically (male-preferring) primogeniture culture, meaning the eldest child would be the first in line to inherit family wealth, estate or titles. Only in 2013, with the passing of the Succession to the Crown Act did primogeniture within the monarchy end, removing the power of a male heir to displace an elder daughter in their right to the Crown. The idea of primogeniture is surprisingly widespread and persistent: in Succession, the HBO satirical comedy-drama, about a family's fight to take over a media empire, one character shouts "I'm the eldest boy!" in the finale. He believes his birth position should give him the right to take over his father's position of CEO. (He is actually the second-eldest son, but we won't get into that). "If the social practice is based on birth order, then yes, birth order will impact your outcomes," says Damian. Age is just a number? Age-related experiences can easily be mistaken for a personality trait or behaviour influenced by birth order, the researchers explain. Take the older, "responsible" sibling as an example: "As people grow older, they become more responsible, more self-controlled. So, the firstborn is always going to be older than the later born, and as you observe your children grow, the firstborn will always be more responsible," says Damian. "Another thing is that people become more self-conscious as they grow older," she adds. "So the second-born might appear more sociable and less neurotic, because a 10-year-old is much more happy and full of themselves… compared to the 14-year-old, who's freaking out about everything. That's because they have different challenges." Factors such as children's friendship circles also matter. Multiple studies suggest a link between delinquent peers and delinquent behaviour, for example, so an older child could be more of a rule-breaker depending on the people with whom they surround themselves. Smart siblings As aforementioned, one consistent finding that crops up in birth order research is the link between birth order and intelligence, with firstborns averaging slightly higher in intellect-related traits than younger-borns. "[The intelligence link] mostly shows up in verbal intelligence test results, and it has a very small effect," says Damian. Also, "if you took a test twice, you'll probably score depending on the day or mood, [or] whatever you ate that morning, [or] how long you slept." It may also be explained by cognitive stimulation in the early years of life. Damian points out that the more adults per child you have in a family, the more exposed they are to mature language and vocabulary. But when there are more siblings born into a family, levels of intellectual stimulation might decrease. "So it's not so much that they're genetically smarter or that they have more potential – it's more that they translate into a higher verbal IQ score on the test which could be due to knowing more words, because more adults versus children spoke to them," she says. "With two children, maybe some of that reading time is taken by managing sibling interactions where the verbal input is a little bit less elevated." There are also suggestions that as older siblings tutor younger siblings, or explain things to them, they use "more cognitive resources". Interestingly, these patterns of intelligence aren't replicated globally. Data from developing countries differs to data from developed countries, for example. In Indonesia, later-born siblings are likely to have better educational opportunities than their older siblings, potentially due to financial constraints, easing only when older siblings begin contributing to family income. According to Damian and her colleague, birth order has "negligible effects" on careers, too. In the past, there an idea prevalent among scientists was that the older sibling would enter a more academic or scientific career, and the younger a more creative one. But Damian found the opposite: in her longitudinal study, which looked at a sample of US high students in 1960 and then the same participants 60 years later, first-borns ended up in more creative careers. 'Selfish' only children? Only children often face the stereotype of being more selfish than children born with siblings, supposedly because they do not have to compete for a parents' attention. Recent studies, however, have shown that this is not the case, and that growing up without siblings does not lead to increased selfishness or narcissism. Other research suggests that the social behaviours of only children compared to children with siblings are not large or pervasive, and "may grow smaller with age". Birth order research has typically not included only children on the grounds that they cannot be fairly compared to children who have grown up with siblings. However, it is possible to compare the personality traits of siblings and only children, according to a 2025 paper by Michael Ashton, a professor of psychology at Brock University, Canada, and Kibeom Lee, a professor of psychology at the University of Calgary, Canada. Their study presented some new and fascinating results. It examined the association between personality, birth order, and number of siblings, in 700,000 adults online in one sample and more than 70,000 in another, separate sample. Middle-born and last-born siblings averaged higher on the "Honesty-Humility" and "Agreeableness" scales than first-born siblings. "Honesty-Humility" measures how honest and humble a person is, meaning, a high-scoring person is unlikely to manipulate others, break rules, or feel entitled. A low-scoring person may be more inclined to break rules and may feel a strong sense of self-importance. On the agreeableness scale, a high-scoring person tends to be forgiving, lenient in judging others, even-tempered and willing to compromise, while a low-scoring person may hold grudges, be stubborn, be quick to feel anger, and be critical of others. "These differences were quite small in size, particularly when the comparisons involve people from families having the same number of children," Ashton and Lee say in an email. "In contrast, the differences in these dimensions between persons from a one-child family (i.e., only children) and persons from a six-or-more-child family were considerably larger, somewhere between the sizes that social scientists would call 'small' and 'medium'." So, I ask, is the influence of birth order just a zombie theory – a concept that is wrong but which refuses to die? Rohrer disagrees. "I'm not sure whether I would call it a zombie theory," she says. "From the scientific perspective, I think the literature is progressing quite productively." So we may, one day, have a clearer answer as to what it means to be an eldest daughter. Until then, I'll keep letting my younger sister believe I'm inherently smarter than her. -- For more science, technology, environment and health stories from the BBC, follow us on Facebook, X and Instagram.