Posts Tagged ‘David Robson’

Why Don’t Our Brains Get Bigger?

December 12, 2018

This post is based on an article by David Robson titled “A Brief History of the Brain” in the New Scientist Collection titled “Becoming Human.”

The question raised in the title seems to be reasonable. Most developments are based on our brains aided by technology. Some even raise the fear that technology will outsmart us and take control.

Here is the answer provided in Robson’s article. Perhaps the most obvious answer is that we reached a point at which the advantages of bigger brains started to be outweighed by the dangers of giving birth to children with big heads. Another possibility is that it might have been a case of diminishing returns.

Our brains burn 20% of our food at a rate of about 15 watts, and any further improvements would be increasingly demanding. Simon Laughlin at the University of Cambridge compares the brain to a sports car, which burns ever more fuel the faster it goes.

For example, one way to speed up our brain would be to evolve neurons that can fire more times per second. However, to support a 10-fold increase in the “clock speed” of our neurons, our brain would need to burn energy at the same rate as Usain Bolt’s legs during a 100 meter sprint. The 10,000 calorie a day diet of Olympic swimmer Michael Phelps would pale in comparison.

The size of our brains ceased increasing around 200,000 years ago. In the past 10,000 to 15,000 years the average size of the human brain compared with our body has shrunk by 3 to 4 percent. However, size is not everything, and it’s possible that the brain has simply evolved to make better use of less grey and white matter. That seems to fit with some genetic studies, which suggest that our brain’s wiring is more efficient now than it was in the past.

It appears that further development depends on humans developing a neo-symbiotic relationship with technology. See the Healthymemory blogpost, “Neo-Symbiosis and Transactive Memory.”

The Science of Voodoo

September 1, 2018

This post is taken from Feature article by David Robson in the 25 August 2018 issue of the New Scientist.

When anthropologists first heard reports of witch doctors killing people with a curse, they looked for rational explanations. These were undermined, however, by the discovery that Western doctors have similar powers. In the 1970s, for example, a man dies just months after doctors told him he had end-stage liver cancer—despite the autopsy revealing that the diagnosis had been mistaken. He hadn’t died from cancer, but from believing he had cancer.

We now know what lies behind these strange goings: the nocebo effect. The “evil” twin of the placebo effect of he placebo effect, it is when putting someone in a negative frame of mind has adverse consequences for their health or well being. Tell people that a medical procedure will be extremely painful, for example, and they will experience more pain than they would otherwise. Similarly warning about the possible side effects of a drug makes it more likely that patients will report experiencing those effects.

The nocebo effect is widespread: about a quarter of participants in clinical trials experience side effects even when they have been given a placebo, a sugar pill. Recent research indicates that it can be even stronger than the placebo effect, particularly when people are anxious or feel that their doctor doesn’t understand or believe them. And the nocebo effect is not just a problem in healthcare. It could also be undermining your efforts to lose weight, shape, cope with stress, and more.

Everyday Placebos

August 31, 2018

This post is taken from Feature article by David Robson in the 25 August 2018 issue of the New Scientist.

Caffeine: If a strong espresso sets your nerves jangling, that may be large to your expectations. Even pure water increased alertness and raised blood pressure in volunteers who were told it contained caffeine. As for those withdrawal symptoms when you can’t get your morning cup of Joe, they might be all in your head, too.

Sports supplements: There is little scientific backing for many of these products, but studies show that people only have to believe they are taking performance enhancers or energy drinks to show greater stamina and strength. Even the effects of steroids may be boosted by a placebo response.

Designer brands: Are they really better than generics? Not necessarily. People tricked into thinking they were wearing designer sunglasses could more easily decipher small writing through the glare of a bright light than those who thought they were wearing less prestigious brands.

Booze: Drinking culture is full of urban myths, including the idea that adding Red Bull to vodka “gives you wings.” Studies reveal that the power of expectation is what really increased feelings of drunkenness.

Lucky charms: They work because we believe they will. Golfers who thought they were using a professional’s putter perceived the hole to be larger and easier to putt—and were more accurate as a result.

Mind Over Matter

August 30, 2018

The title of this post is the same as the title of a Feature article by David Robson in the 25 August 2018 issue of the New Scientist. The subtitle is: “You really can think yourself healthier and happier.” The article begins, “A positive mindset isn’t just mental—it can trigger physical changes making you fitter, slimmer, more energetic and less stressed. It will even help you live longer.”

Dr. Alia Crum told the global movers and shakers at this year’s World Economic Forum in Davos, Switzerland, “Our minds aren’t passive observers simply observing reality as it is; our minds actually change reality. The reality we experience tomorrow is partly the product of the mindsets we hold today.” Dr. Crum heads the Mind & Body lab at Stanford University.

When she read about the placebo effect as a psychology student she had the following eureka moment: if our expectations can influence the effectiveness of a drug, perhaps something similar can happen in other situations also.

In the course of her research she and her fellow researchers have discovered that our mindset affects everything from our weight and fitness to the physical toll of insomnia and stress, even how well we age. Two people could have identical genes and lifestyles, but one can end up healthier than the other, thanks solely to their different thoughts.

There have been many healthy memory blog posts on placebos, so readers should know that placebos are inert pills used in most clinical drug trials. Participants are randomly divided into two groups: half taking the drug being tested, the control group taking an identical looking sugar pill. With no active ingredient, the placebo shouldn’t have any effects. Yet it typically results in measurable changes triggering the release of natural painkillers and lowering blood pressure, for example—all due to people’s expectations. Patients can even show these benefits when they know they are taking a placebo. There is also a nocebo effect. Expectations of a pill can also produce side effects such as nausea and skin rashes.

Crum was surprised that relatively little has been done to understand and harness the facts to improve health and well-being. Governments spend large amounts of money encouraging us to adopt healthier lifestyles. Crum wondered what if our efforts could be boosted or undermined by the very psychological processes that influence a drug’s efficacy through placebo and nocebo effects. She has spent the past decade investigating this possibility.

In one of her first experiments she examined the fitness of 84 hotel cleaners. She suspected that few of them would be aware of the sheer amount of exercise their job entails, and that this might prevent them from gaining the full benefits of that workout. To manipulate their mindsets, she gave half of them detailed information about the physical demands of their work—that their work hoovering burns 200 calories an hour—and told them that their activity met the US surgeon general’s exercise recommendations. One month later, despite reporting no change to their diet or activity outside work, the cleaners who received the information had lost about a kilogram each, and their average blood pressure had dropped from elevated to normal. The others showed no difference. This was a small study and Crum didn’t record actual behavior. She concedes, “It could be that they were putting slightly more oomph into making the beds.”

A follow-up study with a colleague, Octavia Zahrt, bolstered the idea that people’s expectations directly influence their body’s response to exercise. That study used data from health surveys monitoring more than 60,000 people. Zahrt found that the “perceived fitness” of the participants—how they felt compared to the average person—was a better predictor of their risk of mortality than the amount of time they said they spent exercising. Some of them wore accelerometers for part of the survey period. Still, after taking their actual physical activity into account, the influence of how they perceived fitness remained. Overall, people who took a more pessimistic view of their fitness were up to 71% more likely to die during the survey, compared with those who thought they were more active than average—regardless of their exercise routine.

The brain can directly control blood pressure through the autonomic nervous system. Crum suspects that a poor perception of your fitness could be triggering inflammation and the release of hormones such as cortisol, which might help determine how the body responds to stress. Her team is investigating possible mechanisms but, she says, it’s not too early to take advantage of these effects. Cruz’s advice is not to deceive yourself about your fitness, but to make sure that you don’t undervalue the exercise you do, either. Also avoid comparing yourself critically with your peers particularly if they are exceptionally sporty.

Crum has also documented other ways in which our mindset could be harming our health. A nocebo effect could undermine efforts to lose weight by dieting. In 2011, Crum offered volunteers a milkshake at her lab, then measured their levels of the “hunger hormone” ghrelin, which normally drops after a meal. Although everyone received the same shake, some were told it was healthy while others were led to believe they were having an indulgent treat. Those who thought they had drunk a low-calorie shake showed markedly higher levels of ghrelin afterwards, which left them feeling less full.

Ghrelin doesn’t affect appetite alone. By signaling food deprivation, the hormone also slows down metabolism, tipping the body towards storing fat rather than burning it. It makes evolutionary sense to reduce energy consumption when resources are scarce, but it is bad news when we are trying to lose weight. Crum says, “When people think they are eating healthily, that is associated with the sense of deprivation. And that mindset matters in shaping our physiological response. Instead, she suggest, dieters should cultivate a “mindset of indulgence,” savoring the texture and flavors of whatever they are eating.

Non dieters could also fall prey to this effect. When drinking a sugary beverage the brain doesn’t seem to recognize the liquid as a source of energy, and fails to adjust digestion accordingly so that we tend to eat more afterwords than if we have eaten solid food containing the same number of calories. We can subvert this effect by changing our expectation. Richard Mattes at Purdue University primed people to believe that the energy drink would solidify once it reached their stomach. As well as lowering gherkin levels, this increased the insulating response after consumption, leaving them feeling fuller. That was followed by a decrease in the daily energy they consumed.

It should not be forgotten that mind over matter is also important for aging. As has been reported in previous healthymemory posts; people who view aging positively live 7.5 years longer than those who associate it with frailty and senility. Negative perceptions are not merely the result of poor health; they can foreshadow symptoms by as much as 38 years.