Archive for the 'Neuroscience' Category

Mar 22 2021

Breaking Through the Uncanny Valley

In 1970 robotics professor Masahiro Mori observed, “Bbukimi no tani genshō,” which was later translated into “uncanny valley”. This refers to an observed phenomenon (first in robots, but also applies to digital recreations) that the more human-like the robot the greater the emotional affinity of people. However, as imitation approaches complete imitation it takes a sharp dip where people actually become uneasy and even revulsed by the not-quite-human face, before going up again as perfection is achieved. That dip in emotional affinity for near human imitation is the uncanny valley. Both roboticists and digital artists have been trying to break through that valley every since it was identified.

Perhaps the most notorious example of this phenomenon in modern popular culture is the CG portrayal of Tom Hanks in the movie Polar Express.  There is something dead about his eyes, which gives him the eerie appearance of an animated corpse. Even the most advanced current CG does not quite break through, but it’s getting damn close.

There are two neurological phenomena at work here. The first, as I have discussed before, is agency detection. Our brains divide the world into things with agency (the ability to act of their own will) and things without. Our brains are wired to then network our perception of things with agency to the limbic system and assign some emotional significance to them. This is why we feel something about our pets but not about a rock. Of course this is an oversimplification, because our brains are massive parallel processors with many circuits all working at the same time. But this is definitely a fundamental component that explains a lot about our reaction to certain things. This concept has even been pushed to the limits – in 1944 researchers made a video of simple two-dimensional shapes interacting with each other on a screen. Subjects spontaneously imbued these shapes with agency and provided elaborate interpretations of their actions and motivations. (A triangle is about as far away from the uncanny valley in the other direction as you can get.)

Neurologically we can see why we have no problem identifying with cartoon characters, responding to their personality, and even getting invested in their story. Added to this is the brain wiring behind seeing faces and reading emotion. This too can be stripped down to basic components – which is why we can interpret emoji’s. Cartoonists learn how to convey a range of emotions with a few lines. This in turn is partly due tot he fact that we have a large area of our visual cortex dedicated to processing information about human faces. Even infants will prefer to look at a human face over other stimuli. We also have a tendency to construct visual stimuli as a face – which is why we can see faces everywhere, such as in low-res images from the surface of Mars, or in the bark of a tree.

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Mar 16 2021

Lose Yourself

Published by under Neuroscience

How absorbed to you become when you read fiction? How immersed in the world, how connected to the story, and how much do you identify with specific characters? More importantly (from a neuroscientists point of view), what is happening in your brain when all this going on?

A recent study brings all this into focus, looking at fMRI activity while people think about themselves, their close friends, and fictional characters from a popular work of fiction, the Game of Thrones saga. Prior research shows that when we think about ourselves, or access autobiographical information, a particular part of the brain becomes active – the ventral medial prefrontal cortex (vMPFC). When this part of the brain is damaged people have impaired ability to access autobiographical information.

Always I have to add the caveat that the human brain is a complex mesh of different networks producing any end-result. It is difficult, to say the least, to tease apart all these components, especially for any higher-level function. But we can get a glimpse into some specific components that influence specific brain functions in order to flesh out our neurological map. With that said – what did the study find?

They looked at activation of the vMPFC when subjects thought about themselves, about 9 of their close friend, and about 9 characters from Game of Thrones. Not surprisingly, the activation was greatest for the self, least for the fictional characters, and intermediate for close friends (on average). It was known from prior research that we respond neurologically to close friend more similarly to ourselves, so this was not surprising. I will get into why this may be in a bit.

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Mar 09 2021

Reading Attraction in the Brain

I have been tracking the research in brain-machine interface (BMI), specifically with an eye towards studies that claim to interpret brain data. Typically I find that such studies are overhyped, at least in the press release and subsequent reporting. The question I always ask myself is – what exactly are they measuring and interpreting? A new study, using BMI and a form of AI called Generative adversarial neural networks (GANs), claims to read brain data to determine what faces subjects find attractive. What are the researchers doing, and what are they not doing?

The ultimate goal of BMI research (or at least one goal) is to figure out how to interpret brain activity so well that it is essentially mind-reading. For example, you might think of the word “cromulent” and a machine reading the resulting brain activity will be able to interpret it so well that it can generate the word “cromulent”. This would make possible a fully functional digitial-neural interface, like in The Matrix. To be clear – we are no where near this goal.

We have picked some of the low-hanging fruit, which are those areas of the brain that function through some form of somatotopic mapping. Vision is the most obvious example – if you are looking at the letter “F”, neurons in the visual cortex in the literal shape of an “F” will become active. Visual processing is much more complex than this, but at some level there is this bitmap level of representation. The motor and sensory parts of the brain also follow somatotopic mapping (the so-called homonculus for each). There is likely also a map for auditory processing, but more complex and we don’t fully understand it.

The big question is – what are the conceptual maps? Physical maps representing space, images, even sound frequencies, are easy to understand. What are the neural map for words, feelings, or abstract concepts? Related to this is the concept of embodied cognition – that our reasoning derives ultimately from our understanding of the physical world. We use physical metaphors to represent abstract concepts. For example, an argument can be “strong” or “weak”, your boss is hierarchically “above” you, you may have “gone too far” with a wild idea that is a “stretch”. This may just be how languages evolved, but the idea of embodied cognition is that the language represents something deeper about how our brains work. Perhaps even abstract concepts are physically mapped in the brain, anchoring even our abstract thoughts to a physical reality. Perhaps embodied cognition is not absolute, but more of a bridge between the physical and the abstract, or a scaffold on which fully abstract ideas can be cortically mapped. We are a long way from sorting all this out.

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Mar 04 2021

Cuttlefish Pass Marshmallow Test

Cuttlefish are amazing little critters. They are cephalopods (along with octopus, quid, and nautilus), they see polarized light and can use that to change their skin color to match their surroundings. They have eight arms and two tentacles, all with suckers, that they use to capture prey. They, like other cephalopods, are also pretty smart. And now, apparently, they are also in the very elite club of animals who can pass the marshmallow test.

The “marshmallow test” is a psychological experiment of the ability to delay gratification. The basic study involves putting a treat (like a marshmallow, but it can be anything) in front of a young child and telling them they can have it now, or they can wait until the adult returns at which time they will be given two treats. The question is – how long can children hold out in order to double their treats? The interesting part of this research paradigm are all the associated factors. Older children can hold out longer than younger children. The greater the reward, the more children can wait for it. Children who find ways to distract themselves can hold out longer.

For decades the test and all its variations was interpreted as a measure of executive function, and correlated with all sorts of things like later academic and economic success. However, more recent studies have found (unsurprisingly) that there can be confounding factors not previously recognized. For example, children from insecure environments have not reason to trust that adults will return with more treats and therefore take what is in front of them. This could be seen as an adaptive response to their environment.

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Feb 23 2021

Communicating While Dreaming

Published by under Neuroscience

We remember our dreams to varying degrees, but we all dream. Even people who never remember dreaming, dream. Dreaming is detected clinically by what is called REM sleep, for rapid-eye movements. When we dream a part of our brain stem (the locus ceruleus) reduces our response to external stimuli and also is involved in inhibiting our voluntary movements below the brainstem so that we don’t act out our dreams. The pathways to the eye muscles are spared this paralyzing effect, which is why we still move them when we dream.

An ongoing question of research involves understanding exactly what the dreaming state is. It is an altered state of consciousness. We are still conscious in that we can think, we can experience our own existence, and we even can form memories. But all of these functions are altered. At a gross level, brain activity during REM and wakefulness are very similar – if you look at an EEG, for example, the electrical activity of the brain in both states is similar. As researchers are looking with more sophisticated tools, like functional MRI scans, they are finding that activity, again, is largely similar:

Results revealed activity in areas of the brain that control sight, hearing, smell, touch, balance and body movements.

One area that may be different, though, is the frontal cortex, with studies finding decreased frontal cortex activity during REM vs wakefulness. This is obviously a very quick summary of a very complicated area of neuroscience, but the bottom line for the purposes of this article is that the brain is very active when we are dreaming, we are in some sort of state of consciousness with all the basic brain functions still active, but there are differences likely dealing with the higher functions of cognition. One way to think about this is that our “reality-testing” apparatus operates differently while dreaming. We tend to be more accepting of bizarre events and thoughts in dreams that we struggle to make sense of when later remembering while awake. The dreaming you is still you but it’s a different you, similar to how the drunk you is also you but different.

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Feb 09 2021

Nudging Behavior

Published by under Neuroscience

Like it or not, we live in a society of other people, and we share resources, the environment, and infrastructure. This means that how other people behave and the choices they make affect you, as your choices affect others. Even if you live alone in the woods, your behavior affects the local environment, even if in a small way.  As a result there are multiple layers of complex rules governing how we interact with each other in countless contexts. We have evolved a layer of rules, involving guilt, shame, a sense of justice, and other emotions, that powerfully govern our behavior. We have developed explicit laws and regulations that enforce rules by authority and power. And every culture and subculture tends to develop norms of behavior or “soft” rules that are enforced through peer pressure.

The question is – how do we optimize these rules at every level in order to make our world as good as possible for as many people as possible? This includes balancing many concerns, including individual liberty, that are often at cross-purposes. And of course, different cultures will find a different optimal balance.

Implicit in this question is a more fundamental question – how do we affect people’s behavior? Whether or not we should has already been answered – yes, we should. The alternative in anarchy. Even if you are an extreme libertarian, you still want to influence other people’s behavior, just through market forces rather than laws. And I think even the most extreme libertarian would agree that things like murder should be illegal. Back to the real question, how do we affect behavior? Doing so by fiat definitely works – if you arrest someone and throw them in jail, you are taking direct physical control of their behavior. It seems obvious that such extreme measures should be a last resort, not a primary method of behavior modification.

At the other end of the spectrum is what is called a nudge. A recent study defines nudges this way:

Nudges are low-cost interventions that influence decision-making without limiting freedom of choice and have been tested in the environmental realm of electricity and water saving, reduced meat consumption, recycling, and decreasing private car transportation (Kollmuss and Agyeman, 2002Cheng et al., 2011Osbaldiston and Schott, 2012). Sunstein (2014) notes that nudging refers to “liberty-preserving approaches that steer people in particular directions, but that also allow them to go their own way” (p. 583), and that nudges “are specifically designed to preserve full freedom of choice” (p. 584).

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Feb 04 2021

Is Dunning-Kruger a Statistical Artifact?

Published by under Neuroscience

The short answer to the headline question is – not really, but it’s complicated.

The Dunning-Kruger effect, which I have written about several times before, was first published in 1999 by the named psychologists. The basic effect is this – if you graph self-perception of knowledge in a specific domain and performance on an objective test of that knowledge, there is a typical graph of the relationship between these two things. Specifically, the less people know, the more they overestimate their knowledge. They still rate themselves lower than people who know more, but the gap between perception and reality grows. Further, at the high end (the top quartile) people actually underestimate their relative knowledge, probably because they overestimate average knowledge in the public. And everyone thinks they are above average.

This effect is extremely robust and has been replicated many times in many contexts. As the authors have emphasized before – the DK effect is not about stupid people, it is about everybody. It is not about intelligence, but knowledge.

There is also a distinct effect some are calling a super-DK effect in which in specific knowledge areas, like genetic engineering, the people who low the least think they know the most. This is not just about knowledge, but about misinformation. If people are actively misinformed they will have the illusion of knowledge.

The DK effect has been a cornerstone of science communication and our understanding of how to improve knowledge in the last two decades. However, a recent study calls the basic effect into question – The Dunning-Kruger effect is (mostly) a statistical artefact: Valid approaches to testing the hypothesis with individual differences data. The study essentially showed you can reproduce the DK graph using a randomly generated set of data. How is this possible?

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Jan 25 2021

Anomaly Hunting and Boris Johnson’s Phone Call

The latest internet conspiracy theory involves a phone call between President Biden and Boris Johnson’s. Johnson is the first world leader that Biden has called as president, and the moment has been captured in photographs. What I find most amazing about these pictures is that it is 2021 and the phone at No 10 still has a cord. Perhaps there is a security reason for this. But what “the internet” found most interesting was the lack of cord – in the reflected images in the mirror, that is. This observation even confused journalists:

Even ITV political editor Robert Peston admitted he was left bemused by the image.

He tweeted: “This is flipping weird. The phone cable should be visible in the mirror descending from Boris Johnson’s watch, in this official Downing St picture. It’s not. What is going on?”

This may become the latest blue dress – gold dress internet sensation. When I look at those pictures I absolutely see a phone cord, no problem. But – I can see how someone might, at first, be confused. There is a mild optical illusion created by the angle of the cord in the reflection vs the primary picture. While this is likely to blow over quickly as just a silly internet phenomenon, it does reflect (pun intended) a couple of phenomena worth pointing out.

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Dec 18 2020

Using Machine Learning to Map the Brain

Published by under Neuroscience

One of the great ambitious scientific projects of our time is mapping all the connections in the human brain, known as the “connectome”. It seem obvious how this would advance our understanding of neuroscience, having a similar effect as mapping the human genome on genetics and genetic medicine. The connectome is more complex than the genome, and mapping it is trickier. We are still in the stage where any significant advances in the basic technology of mapping brain connections will have a huge impact. So of course neuroscientists are researching exactly that.

A recent study uses machine learning techniques to optimize the algorithms used to map brain connections using function MRI scans (fMRI). This is perhaps another example of how neuroscience and computer science are increasingly supporting each other. The researchers were using marmoset brains as their subject. First they mapped regions of the marmoset brain using a standard technique that involved injecting a fluorescent tracer into neurons then following where that tracer goes, through neuronal connections to other parts of the brain. This is perhaps the gold standard technique, but involves sacrificing the animal so that the brain can be sliced and examined microscopically. This technique, therefore, cannot be used in humans.

They then mapped the same regions of the marmoset brain using the less invasive technique of fMRI scanning, which can trace the movement of water through neuronal connections in order to map them. The fMRI method, however, is not nearly as precise as the fluorescent tracer technique. It also suffers from many trade-offs, which the researcher likened to camera settings. You can change the settings to produce very different looking pictures. The question is – which settings (which in regard to the fMRI refers to the computer algorithms that analyze the data) give the best picture of the connectome?

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Dec 15 2020

Being Manipulated by Robots

Published by under Neuroscience

How susceptible would you be to suggestion or even manipulation by a robot, or even just a digital AI (artificial intelligence)? This is one of those questions where almost everyone thinks they would not be affected, while in reality many or even most people are. We don’t like to think that our behavior can easily be manipulated, but a century of psychological research tells a different story. There is an entire industry of marketing, advertising, and product placement based on the belief that your behaviors can be deliberately altered, and not just through persuasion but through psychological manipulation. Just look at our current political environment, and how easily large portions of our society can be convinced to at least express support for absurd ideas, simply by pushing the right buttons.

Robots and AI are likely to play dramatically increased roles in our society in the future. In fact, our world is already infused with AI to a greater extent that we realize. You have probably interacted with a bot online and didn’t realize it. For example, a recent study found that about half of twitter accounting spreading information about coronavirus are likely bots. What about when you know that an actual physical robot is the one giving you feedback – will that still affect your behavior. Apparently so.

In a recent study psychologists had subjects play a computer game which has already been validated as a marker of risk taking. The game involves hitting the space bar to inflate a digital balloon. As the balloon gets bigger, it becomes worth more digital pennies. You can cash in at any time. However, at random the balloon can also pop, and you then lose all your money. The more risk you take, the more money you can make, but the greater the chance that you lose it all, at least on that go. The researchers had subjects play the game in one of three scenarios – alone, with a robot present who told them when to begin, but then was silent, and with a robot present that would give them encouragement to keep going.

The group with the encouraging robot took significantly more risk in this game than the other two groups, which did not differ from each other. It would have been fun to have a fourth group with a human giving encouragement to see if that differed from the robot – perhaps in a follow up experiment. It’s also interesting that the robot-riskier group made more money than the other two groups. What do these results mean?

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