Archive for January, 2019

Jan 10 2019

Children and Screen Time

Most parents worry about how much time their children are spending in front of computer screens, smartphones, and other electronic devices. This is a reasonable worry – this is a fairly dramatic cultural change, and the experience is different than what most of today’s parents experienced when they were children.

Pediatricians have also been warning about excessive screen time, which has been linked to obesity. But current research and recommendations are getting more nuanced, and pediatric organizations have recently walked back or altered their recommendations.
A recent review published in the BMJ found:

We found moderately strong evidence for associations between screentime and greater obesity/adiposity and higher depressive symptoms; moderate evidence for an association between screentime and higher energy intake, less healthy diet quality and poorer quality of life. There was weak evidence for associations of screentime with behaviour problems, anxiety, hyperactivity and inattention, poorer self-esteem, poorer well-being and poorer psychosocial health, metabolic syndrome, poorer cardiorespiratory fitness, poorer cognitive development and lower educational attainments and poor sleep outcomes. There was no or insufficient evidence for an association of screentime with eating disorders or suicidal ideation, individual cardiovascular risk factors, asthma prevalence or pain. Evidence for threshold effects was weak. We found weak evidence that small amounts of daily screen use is not harmful and may have some benefits.

The evidence is weak, and correlational only. This means we cannot conclude that screen time causes obesity, anxiety, or other issues. It may be, for example, that children who are sedentary for other reasons are both overweight and engage in sedentary activities, many of which involve screen time.
Based on this review, The Royal College of Paediatrics and Child Health said that there is insufficient evidence to conclude that screen time in itself is “toxic.”

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Jan 08 2019

Misunderstanding Dunning-Kruger

Published by under Neuroscience

There is, apparently, an increase recently in interest in the Dunning-Kruger effect. The Washington Post writes about this recently, making the obvious political observation (having to do with the current occupant of the White House). It’s great that there is public interest in an important psychological phenomenon, one central to critical thinking. I have discussed DK before, and even dedicated an entire chapter to discussing it in my book.

Unfortunately the Post misinterpret the DK effect in the common way that it is most often misinterpreted. They write:

Put simply, incompetent people think they know more than they really do, and they tend to be more boastful about it.


Time after time, no matter the subject, the people who did poorly on the tests ranked their competence much higher. On average, test takers who scored as low as the 10th percentile ranked themselves near the 70th percentile. Those least likely to know what they were talking about believed they knew as much as the experts.

The first sentence makes it seem like the DK effect applies only to people who are “incompetent.” This is wrong on two levels. The first is that the DK effect does not apply only to “incompetent people” but to everyone, with respect to any area of knowledge. To be fair the author also writes, “it is present in everybody to some extent,” but this does not really capture the reality, and is undone by the sentences above. Second, the effect applies not just in the range of incompetence, but even for average or moderately above average competence.

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Jan 07 2019

Crowdfunding Quackery

A recent study in The Lancet highlights a disturbing trend – cancer patients using crowdfunding sites to pay for worthless and misleading fake cancer treatments, like homeopathy. They found that in June of 2018 there were 220 active GoFundMe campaigns for “alternative” treatments for cancer.

In this study, which focused specifically on homeopathy (which is 100% complete snake oil), 38% were seeking to use homeopathy in addition to conventional treatment, 29% instead of conventional treatment, and 31% after conventional treatment had failed. The authors, Snyder and Caulfield, were appropriately concerned about these trends.

At this point the most common question to ask is, “What’s the harm.” Well, it is extensive and severe – let me elaborate. In 2017 a study looked at cancer patients, their use of alternative treatments, and their survival. They found that overall if you used alternative treatments you were 2.5 times as likely to die during the study. For the most treatable cancers, like breast cancer, the risk of death was almost six times higher. That is a massive increased death rate. This increased risk of death was controlled for how sick the patients were. The most likely contributor to the increased death rate was delay in conventional treatment.

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Jan 04 2019

Asimov’s Predictions for 2019

Published by under General

In 1984 science fiction writer Isaac Asimov wrote an article for the Toronto Star making predictions for 2019. I thought that was an odd date to pick, but as The Star explains, 1984 was 35 years from the publication of the book by that name, so they wanted to look 35 years into the future.

I am interested in futurism, which is notoriously difficult, but it is an excellent window onto the attitudes, assumptions, and biases of the people making the predictions. Asimov’s predictions are no exception, but they are particularly interesting coming from a professional futurist, and one with a reputation for being particularly prescient.

What did he get right, and what did he get wrong, and why? He focused on what he considered to be the three biggest issues for the future: “1. Nuclear war. 2. Computerization. 3. Space utilization.” I think this list itself reflects his bias as a science-fiction writer. They are reasonable, but he could have chosen medicine, agriculture, transportation, or other areas.

In any case, on nuclear war he was pessimistic in a way that was typical for the height of the cold war, and prior to the collapse of the Soviet Union. He said if we have a nuclear war, civilization is over, so not much more to say about that. Instead he just wrote:

“Let us, therefore, assume there will be no nuclear war — not necessarily a safe assumption — and carry on from there.”

He spent most of the article focusing on the impact of computers on society. This was a frequent topic of his fiction. He famously was correct in his prior visions of the future in the broad brushstrokes of – computers will get more powerful, more intelligent, and more important to civilization. But he also famously got the details wrong, imaging giant computers running things. He missed the trend toward smaller, ubiquitous, and embedded computers.

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Jan 03 2019

Magic Can Increase Belief in Pseudoscience

Magicians play a significant role in the skeptical movement. They have, as Liam Neeson famously said, a particular set of skills. They are very adept at deception, using techniques that have been honed through trial and error over centuries. It is a great example of cultural knowledge. Having the ability to deceive others, purely for entertainment and with informed consent, also makes them adept at detecting the use of the same techniques for nefarious purposes. This, essentially, has been James Randi’s entire career.

But at the same time some stage magicians make skeptics uncomfortable by not being entirely upfront with their audience. Now, I am not suggesting that all magicians tell their audience how the tricks are done, and I completely understand the need to create a mystique as part of the performance. However, I have seen skilled magicians (like Randi or Banachek) perform amazing tricks with complete candor about the nature of those tricks, without diminishing the entertainment value.

Magicians typically create a narrative by which they “explain” their tricks to the audience. A magician, for example, could say, “I am using sleight of hand.” Or they could say (or strongly imply), “I have true psychic ability.” The Amazing Kreskin falls into this latter category. There are also those like Uri Geller who (sort of) pretend they are not doing magic at all, but have special powers.

In the gray zone are those like Derren Brown. Their narrative is not that they are psychic but that they are using psychological manipulation on their audience – reading microexpressions, influencing their decision-making, or reading body-language. This narrative is as much BS as the psychic one, used as part of the magic experience and for misdirection. You can read and influence people to some degree, but these techniques are not reliable enough to support a performance. Typically mentalists use standard sleight of hand and then pretend to use psychological techniques.

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