Archive for the 'Neuroscience' Category

May 18 2017

Follow Up on Bem’s Psi Research

telepathyAn interesting article in Slate by Daniel Engber reviews the story of Daryl Bem and his psi “Feeling the Future” research. If you are interested in this sort of thing the entire article is worth a read, but I want to highlight and expand upon the important bits.

For review, in 2011 Bem published a series of 10 experiments in the Journal of Personality and Social Psychology (JPSP). I wrote about the research at the time, and wasn’t impressed. I wrote:

“In the final analysis, this new data from Bem is not convincing at all. It shows very small effects sizes, within the range of noise, and has not been replicated. Further, the statistical analysis used was biased in favor of finding significance, even for questionable data.”

Bem had taken standard social psychology experimental protocols, mostly dealing with priming, and did an interesting thing – he reversed the order of the experiment so that the priming came after the subjects were tested. For example, he would give subjects a memory test and then let some of them study the material. He claimed that the studying had an effect backward in time to allow subjects to perform slightly better.

For experienced skeptics, this was not much of a surprise. When dealing with claims that have a vanishingly small prior probability, you need extraordinary evidence to be taken seriously, and this wasn’t it. We were already very familiar with these kinds of results – if you squint just right there is a teeny tiny effect size. But we already knew that experiments are easy to fudge, even unwittingly, and it would therefore take a lot more to rewrite all the physics textbooks. (What is more likely, that the fundamental nature of reality is not what we thought, or Bem was a little sloppy in his research?) The key (as acknowledged by Bem himself) would be in replication.  Continue Reading »

183 responses so far

Apr 21 2017

Some Brain Science Hype

scalp-EEGTwo recent neuroscience news items in The Independent represent exactly the problem with bad science journalism today and the tendency to overhype incremental studies.

Brain-Machine Interface

Here’s the first:

Device that can literally read your mind invented by scientists. An ‘easily operated’ machine linked to a smartphone could be ready within five years.

Um, no.  I have be writing about this technology for years, because it is genuinely interesting and I think is a technology to watch. Several labs have made significant progress in brain-machine interfaces. The idea is that you read the electrical activity of the brain with either scalp electrodes or brain surface electrodes. Scientists have developed software that interprets the EEG patterns and learns to correlate them with the thoughts or intentions of the subject. The subject, in turn, learns to control their mental activity to affect the EEG output.

Here is where the technology stands: With brain surface electrodes, you get a much greater resolution of EEG activity. The software has progressed to the point that monkeys can control a robotic arm with sufficient subtlety to feed themselves.

With humans we have mostly used scalp electrodes, which have a more blurry signal. Even with these people have learned to control robots or control a cursor on a computer.

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87 responses so far

Apr 10 2017

New Study on Long Term Memory

Published by under Neuroscience

memory-brainThere is something I never fully understood about memory, and now a new study might clarify my confusion.

The current model of how short and long term memory work is this. Short term memory is formed in the hippocampus and related structures. The hippocampus is highly plastic, it can change rapidly in order to form new real-time memories. However, this plasticity also has the necessary effect of causing recent memories to rapidly fade as they are overwritten.

Short term memory is actually limited in two ways, by the amount of information it can store, and duration. Studies vary in terms of how long short term memories last, but they all agree that it is from 15 seconds to 3 minutes. Measuring this is trickier than it may first seem, because people can “refresh” their short term memory by rehearsal, or from their long term memory, so you have to control for these factors.

There is also something called working memories, and there are varying concepts of exactly what this is. In essence working memory is short term memory that you are currently focusing on and manipulating. For example, if you do math in your head, you are using working memory.

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288 responses so far

Mar 09 2017

Alzheimer’s and Stem Cells

Published by under Neuroscience

ADA recent article in The Mercury News reports on the work of a neurosurgeon who is injecting fat-derived stem cells into the brains of Alzheimer’s patients. The reports is, unfortunately, typical. It revolves around a heart-wrenching anecdote, while giving the facts with the usual false balance.

This is the perfect storm for dubious treatments – Alzheimer’s disease (AD) is a progressive dementia that causes sufferers to slowly lose their memories and ability to think. It is a growing problem with our aging population. There are some modest symptomatic treatments for AD but nothing which alters the course of the disease, or can stop or reverse it.

There is no doubt that the need for an effective treatment is great, but that does not justify lower the standards of science in medicine. If anything it means we have to be more careful.

Added to this is the hype and allure of stem cells, which are progenitor cells that can turn into specific cell types. The general idea with stem cell therapy is that the stem cells will replace damaged or dying cells, repair organs, and reverse disease. This is tricky technology, however, and as is common the hype is running ahead of the science. That is a recipe for exploitation and quackery. Fake stem cell clinics have popped up around the world, promising cures but just robbing the desperate of their remaining health and large amounts of money.

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33 responses so far

Feb 06 2017

Why Are We Conscious?

Published by under Neuroscience

Dennet-Book 2017In Daniel Dennett’s latest book,From Bacteria to Bach and Back: The Evolution of Minds, Dennett explores a number of issues surrounding consciousness. I have not yet completed the book and so may come back to it again, but wanted to discuss one topic that Dennett covers – why are we conscious in the first place?

Dennett makes a distinction between competence and comprehension. Competence is the ability to perform some task, while comprehension is understanding the task and the process. The former is unconscious, while the latter is conscious.

This touches on Chalmers’ “P-zombie” problem – if we can imagine an organism that can do everything a human does without experiencing its own existence (a philosophical zombie), then why did consciousness evolve at all? There are several possible solutions to this problem. The first is that humans were “designed” to be conscious by whatever agent made us. This introduces unnecessary elements and contradicts established science, so I think we can set that aside.

The second solution is that consciousness is an epiphenomenon. We don’t need to be conscious, but we evolved consciousness as an evolutionary accident. This may be true, but is unsatisfying as it just side-steps the question of what use is consciousness.

The third solution, which I find compatible with the evidence and compelling, is that consciousness is inherent to the functioning of our brains and brings with it specific advantages.

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231 responses so far

Feb 02 2017

What Is Normal?

normal-spider-flyOne of the main themes of this blog is metacognition – thinking about thinking. This is a critically important topic because much of our thinking is subconscious, or it is not explicit. This means we are not aware of exactly how our brains process information and come to certain conclusions or decisions. In fact, we may have false beliefs about how we arrive at our decisions.

Cognitive psychologists study how people think, and knowledge of this field can help us become more aware of the otherwise unrecognized assumptions or processes in our decision-making.

Take an apparently simple concept such as “normal.” What does it actually mean and how do we use this concept to think about the world? (“Normal” has a specific mathematical definition, as in “normal distribution,” but I am not talking about that here.) A dictionary definition might be, “conforming to a standard; usual, typical, or expected.” This doesn’t quite tell us how we decide what is “normal.”

In medicine use of the term “normal” has fallen out of favor, because it is imprecise, and also because it may contain a moral judgment. We still use it when referring to numbers, such as normal blood pressure, but even then it is not conceptually precise. Normal may be different for different people in different situations. When we are making an effort to be clear in our language we will use terms such as “healthy” or “physiological” (which is distinguished from pathological).

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15 responses so far

Dec 23 2016

Man Living with 10% of His Brain?

Published by under Neuroscience

hydrocephalus2Here is the title of a science new story from July 2016: A man who lives without 90% of his brain is challenging our concept of ‘consciousness’. This is an excellent example of horrible science news reporting. It is a cautionary tale of what can happen when a reporter does not adequately vet their story with actual experts.

These are the images from the original paper, which was published in 2007. They are quite impressive and I can see how a lay person might misinterpret them. I can see how a journalist might make assumptions about what they are seeing, and not even know enough to question those assumptions and therefore never asked the experts they interviewed the right questions.

In fact the journalist, Fiona MacDonald, got off on an irrelevant tangent about consciousness, even though this case reports has not implications for our understanding of the neurological basis of consciousness.

I was recently reminded of this case, and the bad reporting surrounding it, by a comment left on a previous blog of mine in which the commenter notes:

Furthermore the author noted, rightly that if a model of externalized consciousness was to be tested, we would have to look for anomalies, cases where the brain does not explain the mind. There has been a case recently where a man who retained only 10% of his brain by mass was found to function semi normally with an IQ of 75, a job, a wife and two kids.

So he was offering this case report as an anomaly which calls into question our model of consciousness.

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274 responses so far

Dec 22 2016

Mental Illness and Demonic Possession

A recent article by Emily Korstanje details the story of Nadia, an 18 year old girl from Saudi Arabia who suffered from depression. Her religious parents took her to a faith healer who, through dubious methods involving choking her until she passed out, concluded that her symptoms were the result of demonic possession.

Fortunately Nadia was able to break away from that healer and defy her parents, but she still faces a more difficult challenge – her society.

“They need to separate religion from psychology, especially for us women, who suffer from depression because of our shitty circumstances, or we cannot—and will not—get help,” Nadia sad. “Society also needs to be rid of this of shame toward mental illness and stop saying that people are weak or not perfect believers, or possessed! Spirituality is important but it doesn’t mean that you deny what is really going on because it will only get worse.”

In the past, before science helped us understand things like psychology and neuroscience, it is understandable that prescientific cultures would reach for superstition to explain mental illness and neurological disorders. They had no way of understanding what a seizure was, let alone schizophrenia. So they used what explanations they had at hand and decided that such individuals were possessed by evil spirits, or cursed, or were being punished by god or the gods.

It amazes me, however, that in the 21st century this still occurs. Now, with all the knowledge of modern neuroscience, there is no excuse for confusing a brain disorder with spiritual possession. Further, we do not need to look to third world countries to find example – this is still happening in modern industrialized nations.

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78 responses so far

Dec 05 2016

Westworld and Consciousness

westworld1The season finale of Westworld aired last night, a series based on a Michael Crichton book which was made into a 1973 film. I won’t give much away, so only very mild spoilers for those who haven’t seen it. I will say the last episode was probably the best of the season.

The basic premise of the book/film/series is that it takes place in a futuristic theme park in which guests can visit the old west populated by robots that are there solely for their pleasure.  They exist to lose gunfights, for sexual pleasure, to be victims or fill whatever role the guests want, and then be recycled to run through their plot loop all over again.

The HBO series uses the story line as an opportunity to explore the basic question of sentience. The robots are hyperrealistic. Unless you cut them open, you cannot tell them from a living human. They are extremely realistic in their behavior as well.

The robots clearly have a very advanced form of artificial intelligence, but are they self-aware? That is a central theme of the series. They have complex behavioral algorithms, they can reason, they express the full range of human emotions, and they have memory. They are kept under control largely by wiping their memory each time they are repaired, so that they don’t remember the horrible things that were done to them.

Some of the robots, however, start to break out of their confines. They “feel” as if they are trapped in a recurring nightmare, and have flashes of memory from their previous loops.

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60 responses so far

Oct 18 2016

The Hawthorne Effect Revisited

Published by under Neuroscience

It’s always more complicated than you think. If there is one overall lesson I learned after 20 years as a science communicator, that is it. There is a general bias toward oversimplification, which to some extent is an adaptive behavior. The universe is massive and complicated, and it would be a fool’s errand to try to understand every aspect of it down to the tiniest level of detail. We tend to understand the world through distilled narratives, simple stories that approximate reality (whether we know it or not or whether we intend to or not).

Those distilled narratives can be very useful, as long as you understand they are simplified approximations and don’t confuse them with a full and complete description of reality. Different levels of expertise can partly be defined as the complexity of the models of reality that you use. It is also interesting to think about what is the optimal level of complexity for your own purposes. I try to take a deliberate practical approach – how much complexity do I need to know?

The Hawthorne Effect

The distilled narrative of what is the Hawthorne Effect is this – the act of observing people’s behavior changes that behavior. The name derives from experiments conducted between 1924 and 1933 in Western Electric’s factory at Hawthorne, a suburb of Chicago. The experimenters made various changes to the working environment, like changing light levels, and noticed that regardless of the change, performance increased. If they increased light levels, performance increased. If they decreased light levels, performance increased. They eventually concluded that observing the workers was leading to the performance increase, and the actual change in working conditions was irrelevant. This is now referred to as an observer effect, but also the term Hawthorn Effect was coined in 1953 by psychologist J.R.P. French.

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