20/05/2012 by admin.

A method called fMRI-adaptation has been used to show a neural population that is activated by whole individuals rather than just faces or bodies. The fMRI-A effect depends on the adaptation or attenuation of the BOLD signal because of the repetition of a specific stimulus in a neural population that is sensitive to that particular stimulus.

So far fMRI-A has been used to characterize the representations underlying neural responses to a number of visual stimulus classes including faces, headless bodies, objects, scenes, as well as more generally to the binding of objects and background scenes and to the coding of objects presented in peripersonal space.

Schmalzl, Zopf, and Williams have recently published a paper (see citation below) in which they use fMRI-A to investigate the neural populations that show selective adaptation to the visual presentation of whole individuals, as opposed to just isolated faces or bodies.

In the fusiform gyrus and extrastriate regions, they found areas of specific adaptation effects for same faces, same bodies, either same faces or same bodies, same whole individuals, whole individuals whether same or different (individual category classification).

While the existence of voxels that show significant adaptation only when both the same face and the same body are presented points into the direction of response selectivity for whole individuals, it cannot be taken as evidence for it. The adaptation effect for whole individuals could be merely additive, namely a sum of face and body specific responses. That is, it could simply reflect the fact that some voxels contain a mixture of face and body selective neurons whose individual category specific response is not strong enough to yield significant adaptation, but whose combined response is. We therefore took our analysis one step further and defined a superadditive contrast for the SFSB (same face same body) condition. Specifically, we defined a new independent contrast that allowed us to investigate whether for some voxels showing significant SFSB adaptation, this adaptation was actually larger than the sum of the adaptation shown for all other conditions.

Here is their abstract:

Our ability to recognize other people’s faces and bodies is crucial for our social interactions. Previous neuroimaging studies have repeatedly demonstrated the existence of brain areas that selectively respond to visually presented faces and bodies. In daily life, however, we see “whole” people and not just isolated faces and bodies, and the question remains of how information from these two categories of stimuli is integrated at a neural level. Are faces and bodies merely processed independently, or are there neural populations that actually code for whole individuals? In the current study we addressed this question using a functional magnetic resonance imaging adaptation paradigm involving the sequential presentation of visual stimuli depicting whole individuals. It is known that adaptation effects for a component of a stimulus only occur in neural populations that are sensitive to that particular component. The design of our experiment allowed us to measure adaptation effects occurring when either just the face, just the body, or both the face and the body of an individual were repeated. Crucially, we found novel evidence for the existence of neural populations in fusiform as well as extrastriate regions that showed selective adaptation for whole individuals, which could not be merely explained by the sum of adaptation for face and body respectively. The functional specificity of these neural populations is likely to support fast and accurate recognition and integration of information conveyed by both faces and bodies. Hence, they can be assumed to play an important role for identity as well as emotion recognition in everyday life.

Schmalzl, L., Zopf, R., & Williams, M. (2012). From Head to Toe: Evidence for Selective Brain Activation Reflecting Visual Perception of Whole Individuals Frontiers in Human Neuroscience, 6 DOI: 10.3389/fnhum.2012.00108

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17/05/2012 by admin.

Mind-pops are those little thoughts, words, images or tunes that suddenly pop into your mind at unexpected times and are totally unrelated to your current activity. A recent paper showed that mind-pops were more common in schizophrenics than others. (here) That is not what I want to talk about, it just started me thinking about mind-pops – those I or my friends have. What can prompt mind-pops normally?

I view them as part of a normal effect. I’m talking to someone and I suddenly cannot remember the name of the actor in the program I am describing. I consciously ask to myself what that name is and a few minutes later, after the conversation has gone on to something else, the actor’s name pops into my head. I have no doubt about why it ‘popped’ – a process was started to find the name, it took some time, but now it is returning the result. If it ‘popped’ two days later, I might or might not make the connection. If it ‘popped’ two weeks later, I might be puzzled by why that name suddenly appeared in my consciousness.

For many years, I have assumed that there was always a reason, a mind-pop was an answer to a problem of some sort that has been solved unconsciously. It need not be a memory recall problem but often is. We do not know consciously all of the problems that we are currently tackling unconsciously. Many may never have been registered consciously.

Schizophrenics have difficulties with many aspects of thought so it is not surprising that they may have more or even different sorts of mind-pops. This does not mean they are unnatural for the rest of us, or worrisome. They may just be the answer to a problem that we have just, finally, solved.

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14/05/2012 by admin.

New products have teething problems, development bugs; they need beta development, shaking down before they are reliable. We can presume that this may also be true of the evolution of new species. The great innovations come with side-effects. I have encountered people who said this about our chronic back pains being a side-effect of upright walking. It is a great thing but may have a couple of weak spots. We would actually be surprised if evolution didn’t take some time in a shake down of a new species.

A recent paper in Cell by 20 authors (this was really a big international effort) has tackled the question of whether autism is the unfortunate result of the malfunctioning of a relatively new aspect of the human brain. The essence of the paper is given in a press release from Yale:

(the team) identified the evolutionary changes that led the NOS1 gene to become active specifically in the parts of the developing human brain that form the adult centers for speech and language and decision-making. This pattern of NOS1 activity is controlled by a protein called FMRP and is missing in Fragile X syndrome, a disorder caused by a genetic defect on the X chromosome that disrupts FMRP production. Fragile X syndrome, the leading inherited form of intellectual disability, is also the most common single-gene cause of autism. The loss of NOS1 activity may contribute to some of the many cognitive deficits suffered by those with Fragile X syndrome, such as lower IQ, attention deficits, and speech and language delays … it is a more recent evolutionary adaptation possibly involved in the wiring of neural circuits important for higher cognitive abilities. The findings of the Cell paper support this hypothesis. The study also provides insights into how genetic deficits in early development, a time when brain circuits are formed, can lead to disorders such as autism, in which symptoms appear after birth.

There are a couple of aspects that should be brought up in context of this research. First, this is unlikely to be the only cause of autism. Autism is defined as a set of symptoms (and a not too clearly specified set with arbitrary measures – not a yes/no blood test or the like). A number of causes could end up with similar symptoms. Even a number of genetic causes could end up with the same end result.

Second, when the NOS1 activity is disrupted, the brain will not simply step back to a previous version of the homo brain. We should not make the mistake of assuming that our ancestors resembled people with autism. It may be that the functions that were replaced by the products of NOS1 are no longer available.

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11/05/2012 by admin.

There has recently been a review of the relationship between conscious and unconscious processing by van Gaal and others. (Citation below) They looked at an area of common misunderstanding and attempted to clarify it. Here are the highlights of their summarizing discussion:

… we have reviewed recent studies that have focused on the complexity and strength of unconscious information processing in relation to cognitive control (e.g., response inhibition, conflict resolution, and task-switching), the life-time of information maintenance (e.g., working memory, recognition memory) and the possibility to integrate multiple pieces of information across space and time. Unconscious information has been shown to affect various perceptual and high-level cognitive functions and the associated brain areas, including prefrontal cortex. In some cases, unconscious information has been observed to affect behavior and brain activity for relatively long periods of time. Overall, these recent results highlight the power of unconscious information processing, going beyond specific expectations formulated in traditional theoretical models of consciousness and the cognitive functions thought to require consciousness. … one can conclude that the potential function of consciousness might not be related to the initiation of cognitive control functions by specific stimuli that signal the need for increased control (e.g., stop-signals, task-switching cues). These cognitive control operations are probably triggered by a fast feedforward, and unconscious, early sweep of information processing that reaches even regions in the prefrontal cortex. This unconscious fast feedforward sweep can directly affect (the speed of) ongoing cognitive processes. … Although recent evidence has clearly pushed the boundaries regarding the duration of unconscious effects, the general observation is that unconscious events are much less able to elicit (long-term) future behavioral adaptations than conscious events (e.g., post-error slowing, conflict adaptation). Why might this be the case? Theoretical models of consciousness suggest that conscious awareness is related to long-lasting recurrent interactions between (distant) brain regions. This might enable the exchange of information between several spatially separated cognitive modules, which seems to break the automaticity of information processing. Awareness might be beneficial for enabling flexible and durable information processing strategies that are not directly triggered by a specific stimulus, for example when information has to be integrated across longer periods of time to bias information acquisition or signal the need for performance adjustments . Recently, Kunde et al. suggested that awareness might be dispensable when cognitive control is signaled explicitly (by specific control-eliciting stimuli) but not when it has to be inferred implicitly (by the context, or history of events).

van Gaal, S., de Lange, F., & Cohen, M. (2012). The role of consciousness in cognitive control and decision making Frontiers in Human Neuroscience, 6 DOI: 10.3389/fnhum.2012.00121

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02/05/2012 by admin.

Malcolm MacIver has a posting in the Discovery Blog, Science not Fiction. (here) He connects consciousness with the evolution from marine animals to land animals. His argument goes: (1) marine animals cannot see far compared to their speed (2) therefore marine animals can only react quickly to what they sense (3) moving to land increased their ‘perceptual horizon’ 10,000 fold (4) therefore land animals had time to plan their actions rather than simply react (5) planning needs consciousness.

This puts the first such members of the “buena vista sensing club” into a very interesting position, from an evolutionary perspective. Think of the first animal that gains whatever mutation it might take to disconnect sensory input from motor output (before this point, their rapid linkage was necessary because of the need for reactivity to avoid becoming lunch). At this point, they can potentially survey multiple possible futures and pick the one most likely to lead to success. For example, rather than go straight for the gazelle and risk disclosing your position too soon, you may choose to stalk slowly along a line of bushes (wary that your future dinner is also seeing 10,000 times better than its watery ancestors) until you are much closer.

I am not sure I buy this picture, although it could be behind a big step up in consciousness. One problem is that the theory depends heavily on vision being the main sense. Cetacea (dophins, whales) were land animals that returned to the sea. They did not lose their consciousness but used their hearing as their main sense rather than sight. Their perceptual horizons may be as long or longer than ours. Marine animals use tactile sensing of water movements and electrical sensing as well. One would have to look at the perceptual horizon available from all senses to make a tight argument for the buena vista theory.

There is also the Cephalopods (octopus, squid, cuttlefish) which have never been on land but appear to have no problem with planning and the like. They would not have a same sort of consciousness as vertebrates but it is not a given that they lack a very similar function.

On the other hand, consciousness is costly and slower than reflex so it is not likely to be elaborated in environments where it does not give a yield greater than its cost. Read the post for some interesting crystal ball looks as well as the fuller explanation of the theory.

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29/04/2012 by admin.

“What exactly is beauty?”, is an old and unanswered question. It is one of those fringe qualia of consciousness – not a perception but a feeling, like familiarity or certainty, which is attached to a perception. But the criteria for this feeling has never been settled. A recent paper by Ishizu and Zeti (citation below) looks for the traces of beauty in the brain. Here is the abstract:

We wanted to learn whether activity in the same area(s) of the brain correlate with the experience of beauty derived from different sources. 21 subjects took part in a brain-scanning experiment using functional magnetic resonance imaging. Prior to the experiment, they viewed pictures of paintings and listened to musical excerpts, both of which they rated on a scale of 1–9, with 9 being the most beautiful. This allowed us to select three sets of stimuli–beautiful, indifferent and ugly–which subjects viewed and heard in the scanner, and rated at the end of each presentation. The results of a conjunction analysis of brain activity showed that, of the several areas that were active with each type of stimulus, only one cortical area, located in the medial orbito-frontal cortex (mOFC), was active during the experience of musical and visual beauty, with the activity produced by the experience of beauty derived from either source overlapping almost completely within it. The strength of activation in this part of the mOFC was proportional to the strength of the declared intensity of the experience of beauty. We conclude that, as far as activity in the brain is concerned, there is a faculty of beauty that is not dependent on the modality through which it is conveyed but which can be activated by at least two sources–musical and visual–and probably by other sources as well. This has led us to formulate a brain-based theory of beauty.

Of course, there are many other areas of the brain involved in beauty but none with the overlap of vision and hearing found in the A1 part of the orbito-frontal cortex. They give a specific location to their area A1 as a reference for other researchers. This seems to be the seat of an abstract sense of beauty. Facial attractiveness activates A1 or very nearby. This is also in the general area associated with pleasure, reward, desire, value evaluation and judgments. The visual and auditory activity in A1 have a different onset after stimulus and so probably do not follow the same path from some other shared area but arrive independently, musical before visual beauty.

The caudate nucleus also is activated with an intensity matching experience of beauty but only for visual not auditory stimuli. This area has been associated with romantic love.

We might expect that if beauty has an abstract area of activation than ugliness would too. Not so, there seems no overlap of visual and auditory ugliness. Ugliness appears tied to particular sorts of ugliness, not a symmetrical opposite of abstract beauty. It is perhaps an emotional reaction involving fear, disgust or similar.

We did not find activity in A1 of mOFC that correlates positively with the experience of ugly stimuli, although ugliness, too, involves a judgment. Instead, the parametrically modulated activity with the experience of ugliness was confined to the amygdala and left somato-motor cortex. This implies that there may be a functional specialization within the brain for at least two different kinds of judgment, those related to positive, rewarding, experiences and those related to negative ones.

Beauty has a specific neural correlate. Its activation probably depends on the individual, the object and the situation. It is a value judgement in the broadest sense, a positive judgement based on pleasure, desire and reward.

Ishizu, T., & Zeki, S. (2011). Toward A Brain-Based Theory of Beauty PLoS ONE, 6 (7) DOI: 10.1371/journal.pone.0021852

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20/04/2012 by admin.

When I was 17, I was introduced to the idea of ‘personality’ as a serious psychological concept, starting with extroversion/introversion. I did not believe a word of it – I memorized it – gave it back on the exams – but never believed it. Ever since personality has been in the ‘maybe, but probably not’ category or even the ‘who cares?’ category. I do think that people have patterns of thought and behaviour. People are somewhat predictable. But I cannot see these individual patterns as a very few clear patterns (16 or 4 or 5). Nor can I see them as unchanging in any individual. And most importantly, I do not see them as deep, fundamental, differences in how the brain is built or how it operates. I will try to be more open-minded (but with reservations).

Now there is a paper (see citation) that attempts to show differences between the personality types in the ‘big5′ list using the connectivity between brain areas in resting state fMRI. Here is the abstract:

Personality describes persistent human behavioral responses to broad classes of environmental stimuli. Investigating how personality traits are reflected in the brain’s functional architecture is challenging, in part due to the difficulty of designing appropriate task probes. Resting-state functional connectivity (RSFC) can detect intrinsic activation patterns without relying on any specific task. Here we use RSFC to investigate the neural correlates of the five-factor personality domains. Based on seed regions placed within two cognitive and affective ‘hubs’ in the brain—the anterior cingulate and precuneus—each domain of personality predicted RSFC with a unique pattern of brain regions. These patterns corresponded with functional subdivisions responsible for cognitive and affective processing such as motivation, empathy and future-oriented thinking. Neuroticism and Extraversion, the two most widely studied of the five constructs, predicted connectivity between seed regions and the dorsomedial prefrontal cortex and lateral paralimbic regions, respectively. These areas are associated with emotional regulation, self-evaluation and reward, consistent with the trait qualities. Personality traits were mostly associated with functional connections that were inconsistently present across participants. This suggests that although a fundamental, core functional architecture is preserved across individuals, variable connections outside of that core encompass the inter-individual differences in personality that motivate diverse responses.

So the general plan seems to be (1) assign personality categories to the subjects using questionaire (2) predict the brain areas that will have connectivity increased for each personality category (3) pick ‘hubs’ that should be connected to the areas of interest and show the extent of connection of each area to the hubs (4) compare connectivity with prediction.

This is a similar plan to the one used by one of the authors, DeYoung, in 2010 to try and show areas that were larger/smaller could be predicted by personality categories. Again the abstract:

We used a new theory of the biological basis of the Big Five personality traits to generate hypotheses about the association of each trait with the volume of different brain regions. Controlling for age, sex, and whole-brain volume, results from structural magnetic resonance imaging of 116 healthy adults supported our hypotheses for four of the five traits: Extraversion, Neuroticism, Agreeableness, and Conscientiousness. Extraversion covaried with volume of medial orbitofrontal cortex, a brain region involved in processing reward information. Neuroticism covaried with volume of brain regions associated with threat, punishment, and negative affect. Agreeableness covaried with volume in regions that process information about the intentions and mental states of other individuals. Conscientiousness covaried with volume in lateral prefrontal cortex, a region involved in planning and the voluntary control of behavior. These findings support our biologically based, explanatory model of the Big Five and demonstrate the potential of personality neuroscience (i.e., the systematic study of individual differences in personality using neuroscience methods) as a discipline.

I still find the idea of 5 distinct personality traits, frankly, simplistic. It is way too neat and tidy for a complex biological system. However, the group is going about their research in a logical way, so that if personality types (or something similar) are a part of a deep and fundamental aspect of peoples’ thought and behavior, they may show it convincingly. They call their quest ‘personality neuroscience’ – at least they are going for real evidence.

Adelstein, J., Shehzad, Z., Mennes, M., DeYoung, C., Zuo, X., Kelly, C., Margulies, D., Bloomfield, A., Gray, J., Castellanos, F., & Milham, M. (2011). Personality Is Reflected in the Brain’s Intrinsic Functional Architecture PLoS ONE, 6 (11) DOI: 10.1371/journal.pone.0027633

DeYoung, C., Hirsh, J., Shane, M., Papademetris, X., Rajeevan, N., & Gray, J. (2010). Testing Predictions From Personality Neuroscience: Brain Structure and the Big Five Psychological Science, 21 (6), 820-828 DOI: 10.1177/0956797610370159

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11/04/2012 by admin.

There is a recent study by Scheinin of Turku Finland, his team, and collaborators from U of California. (see citation below). They looked for the neural correlates of consciousness. This is a very interesting study.

They start with some differences in what is meant by ‘consciousness’. They are looking for the correlates of the ’state’ of consciousness as shown by responsiveness to a verbal command.

Consciousness research can roughly be divided into two categories: (1) studies on the contents of consciousness and (2) studies on consciousness as a state. Whereas theories on the particular contents of consciousness, such as visual consciousness, argue for the importance of cortical structures, theories focusing on consciousness as a state stress the importance of subcortical or thalamocortical structures. There is limited human data on which brain structures engage to serve this foundation of consciousness. This study was designed to reveal the minimal neural correlates associated with a conscious state. … General anesthesia is often defined as comprising pharmacologically induced unconsciousness (loss of the ability to feel or experience anything), amnesia (forgetfulness), analgesia (lack of pain), and immobility (not moving in response to surgical stimulation) . In this study, without surgical stimulation, the term “anesthesia” is used to describe pharmacologically induced loss of consciousness. Its objective behavioral criterion was unresponsiveness to a verbal command.

They are aware of some of the short-comings of using aesthesia to study consciousness and try to eliminate them by: using neuroimaging and pattern analysis to dissociate changes in consciousness from other effects of anesthesia; they use an anesthetic that allows awakening during a constant dosing of the drug; they compare arousal with two different drugs; the use of PET as well as MRI. What were the results?

(The authors) investigated what turns back on when consciousness re-emerges following anesthetic-induced unconsciousness. The structures that activated when consciousness resumed were the brainstem, the thalamus, the hypothalamus, and the ACC (anterior cingulate cotex). Although only limited frontal and parietal activity was observed during the return to consciousness, an active parietal region demonstrated greater functional connectivity with the ACC (and other frontal regions) during the conscious state. These findings reveal a functional network that activates with restored consciousness to enable arousal, the subjective awareness of stimuli, and the behavioral expression of the contents of consciousness. … Arousal-induced activations were mostly localized in deep, phylogenetically old brain structures rather than in the neocortex. …suggesting that these deep brain structures form a common foundation for a conscious state. These structures activate also upon awakening from natural Stage 2 sleep, and their direct stimulation can reverse the unconsciousness of anesthesia or improve behavioral arousal following chronic brain injury. … impaired consciousness or coma is known to result from paramedian thalamic and midbrain infarcts.

The activation of the ACC would fit with the test of consciousness in this case being a motor response.

One distinct cortical region activating during the recovery of consciousness was the ACC. This medial prefrontal region has been proposed to play a critical role in consciousness by integrating cognitive-emotional processing with the state of arousal and the intent-to-act. Others suggest that the ACC is a key site of self-regulation of behavior, or might even be involved with the feeling of “free will”. The neuroanatomy of the ACC and its connections with motor control regions suggest that this brain structure acts as the neural interface for translating intentions into actions. This idea is in agreement with studies showing that restored activity in the ACC correlates with the level of responsiveness in brain-injured patients. Our inferior parietal finding may have importance because of its functional connection with the ACC during the conscious state and because of its suggested role in movement intention and motor awareness. In work presented by Desmurget, direct electrical stimulation of the inferior parietal cortex produced in awake brain surgery patients the sensation of a “will to move”. They concluded that conscious intention and motor awareness arise from increased parietal activity before movement execution. This idea fits well with our findings.

Recovery of consciousness is seen as a process:

The recovery from anesthesia does not occur all at once, but rather it appears to occur in a bottom-up manner. When emerging from deep anesthesia there will first be signs of autonomic arousal, followed by a slow return of brainstem reflexes, eventually leading to reflexive or uncoordinated somatic movements that occur somewhat before subjects can willfully respond to simple commands. As shown in our results, only minimal cortical activity is necessary at this point. Thus, emergence of a conscious state, the essential foundation of consciousness, precedes the full recovery of neocortical processing required for rich conscious experiences… All of these data are in agreement with the experiences obtained from hydroanencephalic children, who are devoid of nearly the entire cerebral cortex and yet still display conscious-like behavior. Athough these children have clear deficits in experiencing the rich contents of consciousness, they undoubtedly are in a conscious state, supporting the idea that the subcortical areas identified in our study indicate that consciousness as a process involving both the conscious state and the contents of consciousness likely arises from the interaction between cortical and subcortical mechanism working through specific network connectivity within the brain.

Conscious information processing is pictured as a role of frontoparietal connectivity in the neocortex and is linked to the maintenance of the conscious state by the lower brain through the connections between the neocortex and the thalamus.

I have had the opinion that consciousness is far too complex a process and far too wide-spread through the brain to be of recent origin. In this model, the ’state’ of consciousness could be very old while the particulars of the creation of content for say mammals could be more recent.

Langsjo, J., Alkire, M., Kaskinoro, K., Hayama, H., Maksimow, A., Kaisti, K., Aalto, S., Aantaa, R., Jaaskelainen, S., Revonsuo, A., & Scheinin, H. (2012). Returning from Oblivion: Imaging the Neural Core of Consciousness Journal of Neuroscience, 32 (14), 4935-4943 DOI: 10.1523/JNEUROSCI.4962-11.2012

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08/04/2012 by admin.

On Neuroethics and Law Blog (here) there was reference to a paper giving evidence that scan images do not have the effect on juries that has been reported. Let us hope this is true – scans are far too new and difficult to understand in context, to be used in court if they wield undue influence. I have encountered the opposite view, that scan picture have great influence, but it was with out any evidence, at least where I saw it.

Here is the abstract:

Recent developments in the neuropsychology of criminal behavior have given rise to concerns that neuroimaging evidence (such as MRI and functional MRI [fMRI] images) could unduly influence jurors. Across four experiments, a nationally representative sample of 1,476 jury-eligible participants evaluated written summaries of criminal cases in which expert testimony was presented in support of a mental disorder as exculpatory. The evidence varied in the extent to which it presented neuroscientific explanations and neuroimages in support of the expert’s conclusion. Despite suggestive findings from previous research, we found no evidence that neuroimagery affected jurors’ judgments (verdicts, sentence recommendations, judgments of the defendant’s culpability) over and above verbal neuroscience - based testimony. A meta-analysis of our four experiments confirmed these findings. In addition, we found that neuroscientific evidence was more effective than clinical psychological evidence in persuading jurors that the defendant’s disorder reduced his capacity to control his actions, although this effect did not translate into differences in verdicts.

Schweitzer,N.J., Saks, Michael J., Murphy, Emily R., Adina L., Sinnott-Armstrong, Walter, Gaudet, Lyn M. (2011). Neuroimages as Evidence in a Mens Rea Defence: No Impact Psychology, Public Policy, and Law, 17 (3), 357-393

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05/04/2012 by admin.

Here is a press release from Queens university:

Queen’s University professor Selim Akl has provided additional proof to the theory that nature computes. Dr. Akl (School of Computing) placed rolled oats on a map of Canada, covering the major urban areas. One urban area held the slime mold. The slime mold reached out for the food, creating thin tubes that eventually formed a network mirroring the Canadian highway system.
“By showing species as low as slime mold can compute a network as complex as the Canadian highway system, we were able to provide some evidence that nature computes,” says Dr. Akl.

Humans and human made machines compute (perhaps so do parrots and chimps) but highways and slime molds do not compute. Computing is done with symbols, usually numbers, and with operations on those symbols, usually mathematical or logical operations. There are other ways to arrive at the same solution as a computation, but they are computations just because the end point is the same. Road systems are the way they are because builders were interested in saving time, effort, money. Slime molds are going to save energy while gaining resources. These processes can be modeled mathematically but they are not done in symbolic way.

This attitude has bothered me for years. The mathematics is not more real than the physical thing. Reality is real and mathematics is just a system used to model it. We invented mathematics and it does not exist outside our brains. Nature does not compute except through human thoughts and actions.

It is very interesting that slime molds can reproduce the Canadian highway system with rewards based on the Canadian population distribution – but they did not calculate it – no computation. It was done with biological processes not arithmetic.

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