Archive for the 'Neuroscience' Category

Oct 01 2018

Cheating vs Loyalty

Published by under Neuroscience

How people make ethical decisions is a very interesting line of psychological research. Perhaps the most well-known study is the famous trolley experiment. It is a theoretical question, if you are at the controls of a switch that can change tracks, and a trolley is out of control and heading toward five people that it will surely kill, would you switch the trolley onto another track that only has one person on it? Most people say that they will – they will sacrifice that one person in order to save five.

However, if you are standing next to the track and a very large person is in front of you, would you push them onto the tracks in order to stop the train and save five people (just go with the premise for the sake of the ethical conundrum). Most people will say no. In scenario 1 they will sacrifice one person to save five, in scenario 2 they will not. Why?

Conventional wisdom is that people are more willing to passively allow someone to die rather than actively kill them. The outcome matters less than the mechanism – emotionally, at least.

The deeper issue here, beyond this one ethical calculation, is how we make ethical calculations generally. This mainly comes down to conflict resolution – when competing motivations are moving us toward different behaviors, how do we resolve the conflict? We make such ethical decisions on two levels, intuitive and analytical (the two basic modes of thought that have been elucidated in other contexts as well).

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Sep 06 2018

Superstition and the Illusion of Control

Published by under Neuroscience

Humans tend to be superstitious creatures, meaning that we sometimes believe in magical causation – if I wear my lucky sweater my favorite team will win. Psychologists have been examining this strange phenomenon for decades, with some interesting results.

A recent study ads one more piece of information to the emerging picture of what drives superstitious beliefs and behaviors, but let’s first give some background.

Superstitious beliefs are primarily about the illusion of control – the feeling that we have some direct or indirect control over the outcome of processes over which we objectively have zero control. Gambling is a common everyday example – gamblers tend to develop all sorts of behaviors they believe will give them a better chance of winning at games which are random. Psychologists divide the notion of control into primary and secondary. Primary control is direct control – if I throw the dice with my left hand I will get a better result. Secondary control is an attempt to harness or align with an outside force, such as luck.

It is always difficult to tease apart the complex causes of human decision-making and behavior, and studies necessarily rely on artificial situations or markers of the behavior in question. But a few fairly clear signals have emerged from the research.

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Aug 28 2018

New Neuron Type Discovered in Humans

Published by under Neuroscience

Human brains are perhaps the most complex known structures in the universe (known to us), and while we have discovered a tremendous amount of information about them, there is still much to discover. Recently neuroscientists have discovered a new neuron (brain cell) type, so far discovered only in humans – the rosehip neuron.

Neurons are highly specialized cells in the brain and other parts of the nervous system. They have a general structure that includes a soma, which is the cell body, and projections called dendrites and axons. Generally dendrites are short and numerous and receive electrochemical signals from other neurons. Axons tend to be long and few (often only one) and carry signals away from the soma to other cells. Neurons are therefore a basic component of the nervous system circuit.

Neurons also tend to be either excitatory (increasing the firing of the neuron they synapse on) or inhibitory (decreasing the firing of the neuron they synapse on). Different neuron types are identified by their general shape and their neurochemistry – are they excitatory or inhibitory and what neurotransmitter do they use. The most common neuron type in the cortex is the pyramidal cell, which has a pyramid-shaped soma, a dense bush of dendrites, and one long axon. Pyramidal cells are excitatory and tend to use glutamate as their neurotransmitter.

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Aug 21 2018

Teleology and Conspiracy Thinking

I hate the headline of the Independent article about this new study – “Scientists discover the reason people believe in conspiracy theories.” No, they didn’t. What they potentially found was an additional factor that predicts conspiracy thinking, meaning that it correlates with it.  A much better headline would be – “Scientists find that believing in final causes correlates with conspiratorial thinking,” or something like that.

I understand the need to make headlines eye-catching, but you can do that without misrepresenting the science. The body of the article itself, while it does a decent job of explaining teleology, also misrepresents the implications of the study in a typical way – it fails to put it into the context of existing research.

Mainstream science reporting often follows a typical narrative – we essentially knew nothing, then scientists made this breakthrough discovery, and now we fully understand “the” cause of whatever.

The real scientific narrative is often quite different – we know something about this complex phenomenon, but there is still much that is not known, and now scientists have added one more piece to the puzzle. This is actually, in my opinion, a far more compelling narrative, but you have to tell the whole story of the scientific question, not just the one study.

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Aug 20 2018

Bullshit Research

Published by under Neuroscience

I am not talking about dubious research, but rather research into the phenomenon of bullshit (BS) itself. BS has an operational definition or paradigm within psychological research – it is the extent to which subject rate as highly meaningful statements which are crafted to be vacuous, unconcerned about the truth, and lacking in any unambiguous meaning. Think just about anything Deepak Chopra says. Such statements are also called “pseudoprofound” when they are BS and try to sound profound or philosophical.

“Intuition expresses visible choices.”

“Meditation makes the entire nervous system go into a field of coherence.”

“Experiential truth belongs to the expansion of abstract beauty.”

One of those quotes is from Chopra, the other two from the Chopra simulator.

A recent study extends the research on BS a bit, but first gives a brief summary of what existing research has found:

Recently, some psychological research has focused on individual differences in the extent to which people perceive bullshit as meaningful. These studies have shown that people who rate bullshit sentences as highly meaningful have more religious and supernatural beliefs, are less reflective, intelligent, and numerate, more prone to ontological confusions and conspiratorial ideation, endorse free market policies more, and have more favorable views of Republican presidential candidates in US politics. The aim of this study is to develop the academic field of bullshit further.

Given the relatively few number of references in the paper, it’s probably best to consider these conclusions preliminary. While many of these features make sense, like being prone to believing in the paranormal and conspiracies, I would want to see some independent replication before making any firm conclusion.

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Aug 16 2018

Drug-Induced Near Death Experience

There is no question that people occasionally have strange experiences, sometimes very strange. There is a tendency to interpret such experiences as external, reflecting something happening in the world, rather than internal, reflecting something happening in our brains.

Neuroscience, however, has provided us a powerful tool for understanding some of these experiences. They are a window into how our brains construct our experience of reality, and what we experience when that process breaks down or is altered by drugs, trauma, electrical stimulation, oxygen deprivation, or other stressors.

A recent study looking at the hallucinogen DMT (N,N-Dimethyltryptamine) adds an interesting insight into our collective knowledge of these altered states of consciousness. The researchers studied 13 healthy volunteers, who were given placebo, and then in a separate session a week later DMT, and extensively questioned about their experiences. The researchers specifically wanted to test the possibility that a DMT-induced hallucination would be similar to reported near-death experiences.

In short they found that the DMT experiences were extremely similar to near-death experiences (NDE), but let’s look at the details.

They gave the subjects an established NDE scale, which assesses for 16 features reported by those who experience an NDE. A score of 7 or higher is considered to be a genuine NDE. All 13 subjects scored 7 or higher on this scale when given DMT. Ten of the 16 features were statistically more likely during DMT than placebo. And the total scores were similar to a historical control group of reported NDEs. So again – DMT produced an experience that was very similar to reported NDEs.

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Aug 14 2018

Phantom and Prosthetic Limbs

One of the goals of prosthetic technology (replacement limbs for amputees) is to make the user feel like the prosthetic is part of their body – that they own it and control it (called embodiment). It is more difficult to control a limb that does not feel like part of your body, and users need to visually look at a prosthetic to see where it is. This is true of passive prosthetics as well as robotic ones.

I have written previously about researcher attempts to provide sensory feedback to robotic limbs. A new study adds to this growing knowledge about how embodiment works and how to hack the brain to make it happen.

The key to embodiment seems to be multimodal sensory feedback. If the brain sees and feels the same action, that is all that is necessary for the “ownership module” to kick in – that part of the brain that makes you feel as if you own the various parts of your body. The most primitive manifestation of this is the rubber hand illusion. If you have a rubber hand protruding from your sleeve as if it is your real hand, and you see the rubber hand touched while your real hand is touched (and therefore you feel it), this will create the temporary illusion that the rubber hand is your real hand. Obviously this is not practical for everyday use of a prosthetic.

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Aug 02 2018

Prior Exposure Influences What We See

Published by under Neuroscience

One of the mantras on this blog is that perception is constructed by complex processes in the brain, not a passive recording of external stimuli. The implications of this are profound – what you see, hear, and taste are influenced by your internal model of the world, and what your other senses are telling you. In real time your brain is comparing your sensory inputs to each other, and to stored memories. It then finds the best match possible and (this is critical) tweaks your perception to more strongly conform to the apparent match.

In a very real sense, believing is seeing.

A new study extends our understanding of this constructive perceptual phenomenon a bit with respect to vision. The question was mainly – where in the brain are these processes happening with respect to vision? The researchers used a standard paradigm called Mooney images, which are black and white images degraded so that they are difficult to interpret. However, when primed with an undegraded grayscale version of the image (called disambiguation), it becomes trivially easy to interpret the Mooney image. The effects of this priming may last from days to indefinitely.

The researchers confirmed this priming effect, and that it is very robust. What this means is that what the subjects saw was determined as much, if not more, by their memories (of the disambiguation image) as by their current visual stimuli. What you remember is as or more important than what you are seeing, at least when what you are seeing is ambiguous.

The new information from this study, however, was what brain activity reflects this process. Here they also confirmed prior research that visual processing is very hierarchical – basic processing occurs at primary visual cortical levels, and then goes up to higher levels where more complexity is added and memory becomes a stronger influence. Specifically the researchers wanted to know if the default-mode network (DMN) was playing any role.

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Jul 30 2018

Eye Movements and Personality

Published by under Neuroscience

Have you ever seen someone with “shifty” eyes? How much can we really tell about someone from just their eye movements? This is an interesting question that researchers are exploring. A recent study uses artificial intelligence software to attempt to correlate eye movements of subjects during a specific task with standard measures of personality.

Let’s take a look at this study and then discuss what it all means. Researchers rigged 50 subjects with head gear to record their eye movements:

“Binocular gaze data were tracked using a state-of-the-art head-mounted video-based eye tracker from SensorMotoric Instruments (SMI) at 60Hz. The tracker has a reported gaze estimation accuracy of 0.5° and precision of 0.1°. The tracker recorded gaze data, along with a high-resolution scene video on a mobile phone that was carried in a cross-body bag.”

The data from eight of the subjects was not usable, so they were left with 42 subjects. They recorded an average of about 13 minutes from each subject with about 20% loss of data. They also gave each subject a standardized personality test, and then used an AI learning algorithm to correlate features of eye movement with outcomes on the personality test. They analyzed the data to see how much the eye movements “predicted” the personality traits, and found:

“…our classifier performs well above chance (that is, confidence intervals do not overlap with any of the baseline performances) for neuroticism (40.3%), extraversion (48.6%), agreeableness (45.9%), conscientiousness (43.1%), and perceptual curiosity (PCS, 37.1%). For openness (30.8%) and the Curiosity and Exploration Inventory (CEI, 27.2%) our classifier performs below chance level.”

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Jul 19 2018

Developing Cognitive Biases in Young Children

Published by under Neuroscience

I have discussed a number of cognitive biases over the years, based mostly on research in adults. For example, Kahneman and Tversky first proposed the representativeness heuristic in 1973. But at what age do children start using this heuristic?

A heuristic is essentially a mental short cut. Such short cuts are efficient, and decrease our cognitive load, but they are imperfect and prone to error.  In the representativeness heuristic we rely on social information and ignore numerical information when making probability judgments about people.

In the classic experiment subjects were given a description of the personality of a student, designed to be a stereotype of an engineer. They were then asked how likely it was that the student was an engineering student. Many subjects answered that the student was likely an engineering student, without considering the base rate – the percentage of students who are in engineering. Even when given that information showing it was unlikely the student was an engineer, many subjects ignored the numerical information and based their judgments entirely on the social information.

This can also be seen in the context of general cognitive styles – intuitive vs analytical (or thinking fast vs thinking slow – as in the title of Kahneman’s book). Intuitive thinking is our gut reaction, it is quick and relies heavily on social cues and pattern recognition. It is therefore fast, but is also error prone and subject to a host of cognitive biases.

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