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- 16/12/2011: Fusiform Face Area again
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Archive for November 2008
Metaphor
30/11/2008 by admin.
Again let us have something on the light side.
The last project I was working on before leaving my Toastmaster clubs in
So, today we
Let me give you a little
First a little definition: I am not
Our first stop is
If we think of people as having a cupboard filled with
When speaking, finding an appropriate metaphor can be the most important thing you do to make the communication
Stop number two is effective communication. What makes people change their minds? They come to
Great speeches that have great effects use great metaphors: Churchill’s iron curtain, King Jr’s promissory note,
If those that believe in legal abortions
Stop number three is an examination of how deeply natural is the metaphor. If you
In
The importance of metaphor
It turns out that metaphor is more than a figure of speech, more than a way in which word meanings
If you take the sum total of the metaphoric
Whether we like it or not, we think
Poets use metaphor. In
Two roads diverged in a wood,
I took the
Metaphors
Of course orators use metaphor.
Many whole books
When we use a metaphor we
To sum up: to be a better speaker - use metaphor, use metaphor
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Not inside us
27/11/2008 by admin.
The Edge site has a piece by Alva Noe, The Problem of Consciousness. (here) I find many of the ideas interesting but have a suspicious feeling that the whole thing is just too wooly. It is hard to tell from such a small sampling of his approach. Below are a couple of places where the ideas appealed to me.
“A useful analogy is life. What is life? We can point to all sorts of chemical processes, metabolic processes, reproductive processes that are present where there is life. But we ask, where is the life? You don’t say life is a thing inside the organism. The life is this process that the organism is participating in, a process that involves an environmental niche and dynamic selectivity. If you want to find the life, look to the dynamic of the animal’s engagement with its world. The life is there. The life is not inside the animal. The life is the way the animal is in the world.
….In many ways, the new thinking about consciousness and the brain is really just the old-fashioned style of traditional philosophical thinking about these questions but presented in a new, neuroscience package. People interested in consciousness have tended to make certain assumptions, take certain things for granted. They take for granted that thinking, feeling, wanting, consciousness in general, is something that happens inside of us. They take for granted that the world, and the rest of our body, matters for consciousness only as a source of causal impingement on what is happening inside of us. Action has no more intimate connection to thought, feeling, consciousness, and experience. They tend to assume that we are fundamentally intellectual—that the thing inside of us which thinks and feels and decides is, in its basic nature, a problem solver, a calculator, a something whose nature is to figure out what there is and what we ought to do in light of what is coming in.
We should reject the idea that the mind is something inside of us that is basically matter of just a calculating machine. There are different reasons to reject this. But one is, simply put: there is nothing inside us that thinks and feels and is conscious. Consciousness is not something that happens in us. It is something we do…”
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Occam’s razor and rules of thumb
24/11/2008 by admin.
Occam’s razor (make fewest assumptions, eliminate the unnecessary, the simplest is best, postulate the fewest entities) is a rule of thumb for science. Another rule of thumb is that general theories that cover large amounts of data are preferable to a number of smaller theories covering the same data.
So what can we make of a recent article (here) in the New Scientist where Henry Nicholls reviews attitudes towards the idea of animals having the ability to ‘time travel’ through their memories and imagined futures and are not confined to just living in the present.
“The issue is getting researchers of human and animal minds rather hot under the collar. Critics argue that what looks like memory or forward thinking is nothing more than instinct or learned behaviour, and insist that there is no convincing evidence that non-human animals can remember their past or contemplate the future. As a result, every paper claiming to demonstrate the ability in animals is fiercely debated.”
The article reports on a number of experiments that appear to show memory or foresight and then reports the criticisms. The same disagreements occur fairly often in the areas of animal communication, use of symbols and concepts, calculations, self awareness etc. Sometimes the critics seems to me to be right but more often they appear to be putting forward ideas that do not pass the Occam’s razor test and postulate one theoretical framework for animals and another for humans, with no reason to justify the difference.
Some would say that there is another principle to keep in mind – don’t anthropomorphize. When I look at a chimp and I say he is standing on his legs and waving a branch with his arms, I am not criticized for using the same word for the chimp’s legs and mine or the chimp’s arms and mine. We are allowed to say that an animal is angry or frightened. We recognize homologous features in different animals and ourselves. But if we talk about animals having concepts, we are said to have crossed a line and are anthropomorphizing. This is a circular argument: first we have to define something as a human-only attribute and then we are anthropomorphizing if we use a human-only attribute in the context of an animal. If the attribute had not been defined as uniquely human in the first place then there would be no anthropomorphizing.
There are a number of reasons to avoid failing into the trap of exaggerating the differences between us and animals (especially the intelligent and social ones) and therefore defining ahead of investigation that some explanations only apply to humans.
1. There are experiments that can be done with animals but not humans and vice versa. We can understand both better if we consider what we know about the other.
2. The same reasons that behaviourism is no longer convincing for humans can be applied to animals.
3. The brains of many animals are similar to human brains. There is the same chemistry and physics and biology, the same evolutionary history until very recently, and very similar basic behaviour. There is no enough difference evident to justify two types of explanation. It is not good science to burn bridges or lock doors ahead of experimental evidence.
4. A difference in degree can be large enough to look like a difference of kind.
5. No explanation of human neurobiology is complete without an evolutionary narrative of how it evolved from common ancestors with other primates. This would need to show the steps that connect human thought to animal thought – difficult if there are different mechanisms put forward for what appears to be the same abilities.
6. Humans are unique but so are all species (it is sort of the definition of a species). Humans may even be ‘uniquely unique’ but I doubt that they are the only species that could be called that. But uniqueness is not an important criterion for understanding how brains/minds work – whether an explanation fits depends on the explanation and not on its uniqueness.
7. Science should be protected with other agendas. Part of the motivation for separate explanations for humans and animals is prompted by agriculture, religion, and various philosophical or pragmatic ‘vested interests’.
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Default network
21/11/2008 by admin.
The New Scientist site had an article by Douglas Fox, The Secret life of the Brain,
“The brain areas in the network were known and previously studied by researchers. What they hadn’t known before was that they chattered non-stop to one another when the person was unoccupied but quietened down as soon as a task requiring focused attention came along. Measurements of metabolic activity showed that some parts of this network devoured 30 per cent more calories, gram for gram, than nearly any other area of the brain.
All of this poses the question - what exactly is the brain up to when we are not doing anything? When Raichle and Shulman outlined the default network, they saw clues to its purpose based on what was already known about the brain areas concerned.
One of the core components is the medial prefrontal cortex, which is known to evaluate things from a highly self-centred perspective of whether they’re likely to be good, bad, or indifferent. Parts of this region also light up when people are asked to study lists of adjectives and choose ones that apply to themselves but not to, say, Britney Spears. People who suffer damage to their medial prefrontal cortex become listless and uncommunicative. One woman who recovered from a stroke in that area recalled inhabiting an empty mind, devoid of the wandering, stream-of-consciousness thoughts that most of us take for granted.
Parts of the default network also have strong connections to the hippocampus, which records and recalls autobiographical memories such as yesterday’s breakfast or your first day of kindergarten.
To Raichle and his colleague Debra Gusnard, this all pointed to one thing: daydreaming. Through the hippocampus, the default network could tap into memories - the raw material of daydreams. The medial prefrontal cortex could then evaluate those memories from an introspective viewpoint. Raichle and Gusnard speculated that the default network might provide the brain with an “inner rehearsal” for considering future actions and choices.
…. Daydreaming may sound like a mental luxury, but its purpose is deadly serious: Buckner and his Harvard colleague Daniel Gilbert see it as the ultimate tool for incorporating lessons learned in the past into our plans for the future. So important is this exercise, it seems, that the brain engages in it whenever possible, breaking off only when it has to divert its limited supply of blood, oxygen and glucose to a more urgent task.
…. In support of this idea, Raichle points out that the default network constantly chatters with the hippocampus. It also devours huge amounts of glucose, way out of proportion to the amount of oxygen it uses. Raichle believes that rather than burning this extra glucose for energy it uses it as a raw material for making the amino acids and neurotransmitters it needs to build and maintain synapses, the very stuff of memory. “It’s in those connections where most of the cost of running the brain is,” says Raichle.”
This medial pre-frontal cortex involvement is interesting. I can remember a time when I was very ill with radiation sickness; I sat all day and stared at a blank wall with practically no thoughts. I can understand the lady with the ‘blank mind’. What an apt expression. My default network must have shut down temporarily.
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Decisions without frontal lobe activity
18/11/2008 by admin.
A paper by Tosoni, Galati , Romani, and Corbetta is reported in Science Daily (here). The research shows that once a task is learnt, the frontal lobes are not involved in decision making.
“In Nature Neuroscience, scientists report that a simple decision-making task does not involve the frontal lobes, where many of the higher aspects of human cognition, including self-awareness, are thought to originate. Instead, the regions that decide are the same brain regions that receive stimuli relevant to the decision and control the body’s response to it.
Other researchers had already demonstrated the same principle in primates. But many still assumed that the more complex human brain would have a more general decision-making module that involved the frontal lobe independently of the neural systems for perception and action.
…Maurizio Corbetta, M.D., the Norman J. Stupp Professor of Neurology. “We like to think of our decisions as willful acts, but that may be an illusion. Many decisions may be much more directly and automatically driven by what our brain is sensing.”
… trained volunteers to perform a task that involved discriminating between an image of a face and an image of a building. Varying degrees of noise obscured the image during the brief time it was visible. Volunteers were asked to indicate which type of image they believed they had seen by either moving their eyes in a particular direction if they had seen a face or pointing their hand in the same direction if they had seen a building.
“This decision is not automatic,” Corbetta says. “It requires both attention to the stimuli and control of the response.”
Researchers took functional magnetic resonance imaging scans of subjects’ brains as they performed the task… To help distinguish between the influx of sensory information and the decision to move the eye or hand, subjects had to wait for 10 seconds after seeing the image before indicating which type it was.
“This suggests that these regions in the parietal lobe processed all the sensory, decision and motor signals necessary to make and act on the decision,” Tosoni says. “In contrast, no area in the frontal lobe, thought to be involved in decision-making, significantly increased its activity at the time of decision.”
The training period that preceded the scans could have involved the frontal lobes, Corbetta notes. Those areas may have delegated responsibility for the decision to premotor brain regions as the volunteers learned the task. But once the task was learned, the frontal lobes were silent.
“Even for arbitrary and somehow complex visual decisions, it seems to be purely a matter of the amount of sensory information pushing the brain toward one choice or another ” he says.”
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Metaphors for consciousness
15/11/2008 by admin.
There was another thing that really caught my eye in Baars and McGovern, Cognitive views of consciousness: What are the facts? How can we explain them? (here) They give a list of metaphors that have been used over the years for consciousness.
1. The Threshold Metaphor – a stimulus above a certain value automatically enters consciousness.
2. The Tip-of-the-Iceberg Metaphor – consciousness emerges from the bulk of unconscious processes.
3. The Novelty Metaphor – consciousness is concerned with what is new or unexpected.
4. The integration Metaphor – sensory data is passes from low-level processes to higher-level ones and consciousness is the highest and most integration perceptions.
5. The Executive Metaphor – consciousness produces the ‘self’ that is controlling.
6. The Searchlight Metaphor – the focus of attention is basic to consciousness.
7. The Theater in the Society of Mind Metaphor – access by all parts of the brain to shared information is the function of consciousness.
All of these metaphors have more than a large grain the truth to them, or they would not have lasted so long. But they also each have gaps and problems.
What I noticed, of course, was that my favorite metaphor was missing.
8. The Working Model Metaphor – consciousness is the best-fit scenario of the information available to the brain to model reality.
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Fringe consciousness
12/11/2008 by admin.
In this post I have the definition of fringe consciousness from Baars and McGovern in Cognitive views of consciousness: What are the facts? How can we explain them? (here)
“There is an interesting class of phenomena that are not quite conscious nor unconscious, but which are nevertheless very important for our normal mental functioning. William James thought the ‘fringe conscious’ events were at least as important as focally conscious experiences. Indeed, he thought that perhaps one-third of our conscious lives may be spent in subjectively active but vague states of mind. Fringe events include feeling of rightness, beauty, coherence, anomaly, familiarity, attraction, repulsion and the like. Most people are sure of their judgment when they experience something as beautiful. But is the experience by beauty specifiable in detail, like the sight of a red toothbrush? Surely not for most people, even when they are very sure about the experience. The combination of high certainly, high accuracy, and low experienced detail defines a ‘fringe conscious’ state.
Mangan has developed James’ ideas about fringe consciousness in modern terms, suggestion that fringe phenomena may not be subject to the classical capacity limitations of conscious experiences. The claim is that feelings of familiarity or coherence can be simultaneously present in consciousness along with perceptual contents, for example….The fringe may be, in Mangan’s terms, a ‘radical condensation’ of unconscious information in consciousness. Fringe states seem very useful. There is evidence that they are involved in accurate decision-making, predict resolution of tip-of-the-tongue states, and give a sense of availability of a memory even before it comes to mind….
Research on fringe consciousness is still in its early stages. We can however suggest a useful operational definition for fringe conscious events, as those experiences that: (a) can be reported by all normal subjects in similar tasks, (b) with verifiable accuracy and high confidence; and (c) which can be voluntarily acted upon, (d) but which are not claimed to have differentiated perceptual, imaginal or semantic content; even (e) under optimal reporting conditions.”
It seems a good definition. In the discussion leading to the definition, I have trouble with the continual use of ‘states’. I have never been comfortable with the implied static nature of a ‘state of mind’ and have always thought of mental processes as dynamic. But that is nit-picking as ‘event’ is used rather than ‘state’ in the definition.
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Prediction
09/11/2008 by admin.
There was an interesting item in Discover site by Nina Bai on Oct 28. Apparently tennis refs are biased in the direction of their calls. They make many more mistaken ‘out’ calls than ‘in’ calls. This is the result of an illusion. The refs like everyone else anticipate the motion of an object. Dr. David Whitney had the idea of testing the calls while watching Wimbledon .
“The visual system is sluggish…It takes a hundred or more milliseconds for us to become aware of an image that strikes our retina. If the object is moving fast, the brain produces an illusion that the object has moved slightly further than it actually has in order to overcome this lag.”
This is another example of our consciousness predicting into the very near future.
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More Llinas
06/11/2008 by admin.
More Llinas
Another part of the interview with Llinas is about the primacy of movement. (Encephalon 57 on Mind Hacks has a link to a video interview of Rodolfo Llinas (video)).
“If you look at biology in general, you find that suddenly in evolution, something very interesting happens which is macroscopic animals appeared. And what I mean by that is that a whole bunch of cells that had lived for almost 3 billion years as individuals suddenly came together to form an entity that is larger than any one of them….OK so then you have a set of cells and this set of cells can solve the problem of existing in two very basic ways. One … solves this problem by the universe coming to you; you cannot go to the universe. Those particular entities require no nervous system and have no nervous system – plants don’t have a nervous system. The other solution is to move actively, to be able to displace yourself. Now in order to survive the dynamics of moving, you have to have some idea of where you are moving to. Now the advantages to moving are huge because you can run away from danger. This is non-trivial. … The problem with motricity, with the ability to move, is that you have to have three important properties. First you have to have the ability to move, to be able to displace yourself. Secondly, you’re going to have to have some prediction of where you’re moving, so you need a sensory system that tells you…And the third one, and the most profound, is called intentionality. To decide. If you have the ability to move and you have the ability to predict but you don’t have the desire to move, you don’t.”
“If you are going to move actively, you need a brain. Now the opposite is also the case. Any animal that moves, however primitive, has a nervous system, and as you know it happened almost as an explosion, in an explosive way, a lot of different types of animals appeared with a lot of different types of nervous systems. And by the way when you look at neurons, they’re almost exactly the same regardless what animal you are. Part of the tissue becomes the nervous system that generates motricity by activating muscles, has motricity pattern so you can go forwards or backwards or whatever and has a desire to move intentionality. That is present in all of them….Now because it is so closely related to prediction and so closely related to intentionality then we make an impossible statement and say, you know what, thinking may be nothing else by internalized movement…What it (the brain) does is generate pre-motor acts, inside it generates pre-motor events, all that we can do as human beings with our brain is activation of motor neurons, that is the only output.”
So I would assume that Llinas would not be surprised that our thinking, words and concepts are so often based on a movement metaphor. He is going further than just metaphor.
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Llinas’ experiment
03/11/2008 by admin.
Encephalon 57 on Mind Hacks has a link to a video interview of Rodolfo Llinas (video). There are many interesting ideas in this hour long discussion. The part I am quoting from the transcript is Llinas’ self-experimentation on the subject of free-will.
“…I understand that free will does not exist; I understand that it is the only rational way to relate to each other, this is to assume that it does, although we deeply know that it doesn’t. Now the question you may ask me is how do you know? And the answer is, well, I did an actually lovely experiment on myself. I was extraordinary really. There is an instrument used in neurology called a magnetic stimulator…its an instrument that has a coil that you put next to the top of the head and you pass a current such that a big magnetic field is generated that activates the brain directly, without necessary to open the thing. So if you get one of these coils and you put it on top of the head, you can generate a movement. You put it in the back, you see a light, so you can stimulate different parts of the brain and have a feeling of what happens when you activate the brain directly without, in quotes, you doing it. This of course is a strange way of talking but that’s how we talk. So I decide to put it on the top of the head where I consider to be the motor cortex and stimulate it and find a good spot where my foot on the right side would move inwards. It was *pop* no problem. And we did it several time and I tell my colleague, I know anatomy, I know physiology, I can tell you I’m cheating. Put the stimulus and then I move, I feel it, I’m moving it. And he said well, you know, there’s no way to really know. I said, I’ll tell you how I know. I feel it, but stimulate and I’ll move the foot outwards. I am now going to do that, so I stimulate and the foot moves inwards again. So I said but I changed my mind. Do it again. So I do it half a dozen times… (it always moved inward)…So I said, oh my god, I can’t tell the difference between the activity from the outside and what I consider to be a voluntary movement. If I know that it is going to happen, then I think I did it, because I now understand this free will stuff and this volition stuff. Volition is what’s happening somewhere else in the brain, I know about and therefore I decide that I did it…In other words, free will is knowing what you are going to do. That’s all.”
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