Darwinian Linguistic Evolution

There is a paper by Oudeyer and Kaplan, which discusses the evolution of languages in Darwinian terms. That is a refreshingly new (to me!) take on how languages may evolve. It applies the same Darwinian principles of heritability, variation and selection to individual phonetic words as well as associations between words and meanings.

The article makes use of computer simulations to inform their theory. Some of the take home from that article are:

• For Linguistic coherence to evolve (that is one word referring to same meaning for different agents), the replication principle most suited is whereby the most frequently encountered word is repeated and thus gets fixated in the population. This scores over the use-the-last-heard phoneme rule and use-the-phoneme-as-per-frequency-in-usage rules.
• The phonemes that can be easily confused (are liable to mutate more) with nearby phonemes get selected against and thus, selection leads to implicit evaluation whereby those phonemes that do not mutate (or mutate less) are preferred and get fixated.
• In a population with agents coming and leaving, the population flux ensures that optimal words are used and sub-optimal done away with.
• The linguistic phonemes (or words) that are used to represent concepts, break the acoustic space in such a way that their is least scope for confusion amongst the phonemes.
• A trade-off happens between linguistic distinctively and robustness. Some words are long enough that they can mutate more, but are not easily confusable. Other frequently used words are short and do not mutate easily, but if they mutate than more confusion of meaning arises.

There are more such interesting information nuggets in the paper. So why don't you have a look at the original paper itself.

Hat tip: Babel's Dawn.

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Second Life of Craig J. Phillips

No, I am not talking about the computer game Second life! This post is regarding Mr. Craig J. Phillips, who suffered traumatic brain injury and not only survived, but thrived and currently maintains a blog. He recently contacted me via commenting on this blog and I would like to quote from that and encourage readers to visit his blog and discover with him his journey that was akin to a second life.

My name is Craig J. Phillips. I am a traumatic brain injury survivor and a master’s level rehabilitation counselor. I sustained an open skull fracture with right frontal lobe damage and remained in a coma for 3 weeks at the age of 10 in August of 1967. I underwent brain and skull surgery after waking from the coma. Follow-up cognitive and psychosocial testing revealed that I would not be able to succeed beyond high school. In 1967 Neurological Rehabilitation was not available to me, so I had to teach myself how to walk, talk, read, write and speak in complete sentences. I completed high school on time and went on to obtain both my undergraduate and graduate degrees. For an in depth view of my process please read my post, http://secondchancetolive.wordpress.com/2007/02/18/my-journey-thus-far/

Through out my lifetime I developed strategies to overcome many obstacles and in so doing I have achieved far beyond all reasonable expectations. On February 6, 2007 at the encouragement of a friend I created Second Chance to Live. Second Chance to Live, which is located at http://secondchancetolive.wordpress.com presents topics in such a way to encourage, motivate and empower the reader to live life on life’s terms. I believe our circumstances are not meant to keep us down, but to build us up. As a traumatic brain injury survivor, I speak from my experience, strength and hope. As a professional, I provide information to encourage, motivate and empower both disabled and non-disabled individuals to not give up on their process.

Please encourage your readers to visit Second Chance to Live at http://secondchancetolive.wordpress.com

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Disscoiation between analgesic and addictive effects of pain-killers

Common pain-killers like Morphine have both pair-relieving as well as tolerance and addictive effects. Opiates, it had been theorized earlier, were able to relieve pain via a mechanism that involved the neurotransmitter Serotonin. For the first time , this has been decisively proved to be so, by examining the effects of pain-killer on mice that were engineered to have the serotonin producing gene, Lxmb, silenced in the 5-HT neurons. As such these mice completely lacked serotonin in their brains.

It was found that these mice exhibited more sensitivity to pain and also morphine, or other opiates, were not able to relive the pain in these mice. On the other hand the addictive effects of morphine remained intact.

I am tempted to conjecture further. Is it the case that psychological and physical pain share the same neural substrates? Remember that low levels of serotonin cause depression, in which the sensitivity to psychological pain is elevated. this is similar to the fact that the sensitivity for physical pain is heightened in mice lacking serotonin.I am further tempted to stick my neck out and recommend that the experiment be perormed with mice that have dopamine producing neurons silenced in the brain. If such mice can survive to adulthood, would they exhibit the analgesic effects of morphine, but not its addictive effects? anyway this dissociation between analgesic and addictive effects of morphine would have serious pharmacological effects.

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Good Mood + Intuition = Magical Thinking = Psychosis?

There is a nice little study that shows that good mood induces one to be more superstitious or prone to believe in things like UFO's or the Voodoo dolls.

In the experiment they induced good mood by making people imagine a scenario wherein the participant helped a lost child find his/her parents. The mood was thus experimentally manipulated. subsequently they were showed a documentary about UFOs. Those who were in good mood as compared to neutral mood, were more likely to believe in the UFO's. This was true for only those whose decision making style was intuitive. Those, who were more rationally inclined, were not made to believe in UFO's by the good mood manipulation.

In a follow up study, those who were more happily inclined and intuitive were less successfully at a dart throwing game in which the target was a photo of a baby. This is due to their attributing some similarity to the target with themselves and thus this impedes their performance.


Now, it is well known, that those bipolar patients who are having a high can also have psychosis. Also while depressive phase of bipolar is marked by sad mood (amongst other), the manic phase is characterized by a happy and exuberant mood (although irritability of mood is also present). It thus seems evident that in a manic phase , people who are intuitive may resort to Magical Thinking and this may lead to full blown psychosis as they lose contact with reality. This is an interesting hypothesis and I would like to see some studies on bipolar patients - both those who are rationally inclined and those whose thinking style is intuitive- and investigate is those who have psychotic episodes are more intuitively inclined- as a happy mood is a commonality to all bipolars in the manic phase.

Also, I haven't read the original study - couldn't find on the web- so if someone can point me to a link to the same, or to some other related studies, I would be very thankful.

Hat tip: Mind Hacks

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True Lies: More thoughts on Autism and Schizophrenia

There is a fantastical article by Simon Baron-Cohen about how autistic children are more honest than the rest of us and how the neurotypical human brain is characterized by an ability to deceive.

As we all know, Autistic children have troubles with meta-representation, or believing that there could be two versions of reality- one that is factually correct, and which they themselves may hold; and another that is incorrect, but exists in the mind of another human being. Thus, they may not have any problem with knowing some fact about the world, but are greatly disadvantaged when it comes to knowing facts about other people's mind- as they cannot conceive that somebody can have beliefs that are different from the Reality- in other words that someone has 'false beliefs'.

As per Simon, the capacity to deceive involves the ability to know that one can have false beliefs; and also that one can manipulate the beliefs of another person, so that the person ends up with a false belief. I doubt whether the first ability is necessarily compromised in people with Autism. After all, they themselves may have had false beliefs about the world (say thinking that sun revolves around the earth) and thus may similarly conjecture that others can also have false beliefs. The trouble may lie elsewhere- they may lack the ability to discern that whatever beliefs they have (whether true or false), the other person might not necessarily have the same beliefs. That is they may confuse their own beliefs with that of another and would not have a higher level meta-representation, that someone can have a different belief set. Thus, the trouble is not with having beliefs- but with the ability to say and understand that "I believe that john believes this". They may not comprehend such a sentence or thought- as it is superfluous in their world, where their beliefs are consistent with Reality (or are false) and the other person's beliefs also being consistent with Reality are one and the same. Thus they never require , or are able to use, this recursive ability. I believe this deficit in recursive ability may to some extent explain their language difficulties too. coming back to point, as they themselves cannot comprehend that "I believe john believes X.", so also they are unable to comprehend that 'john believes I believe X". thus, in their innocent and simplistic world, their is no room for either manipulating others via deception; nor of not trusting and always being on their guard against what someone says or does. Thus, they would take sentences at their face value.

I came across this article via The Thinking Blog and there Mary makes some interesting points about whether all deception is bad and all honesty is good; and I concur fully with her that sometimes deception is needed and can be put to good purpose and sometimes truth is not desirable or even moral as per the situation. What is more instrumental is the motive with which the truth or lie is chosen. Thus, I personally am of the opinion that we do need an ability to deceive, but the character to keep the trait in check and to put in good use only.

Simon also makes a point that we treat Autistic traits like honesty as traits on a continuum and not as deficits and I agree with him there too. He treats the normal , social brain as the extreme end of the this trait on which the autistic are the other end; and here I differ. I have already made some strong cases for Schizophrenia to be at the other end; and I would like to support that position by drawing on Simon's analysis.

If we believe that one trait that Autistic lack is deception and meta-representation or ability to read minds, then the Schizophrenics are bound to be too good at it (as per my thinking they are two ends of a creativity spectrum).

• The Schizophrenics may use so much meta-representation (thinking that goes 'I think he thinks that I think that Mary thinks ....') that they may not only get confused, but sound disoriented and disorganized as they may assume too much about what the other person believes. Much of the incoherence in a psychotic speech may be due to too much of shared context - or too much of' he-knows-what-she-knows-that-I-know' sort of thinking. Also keeping multiple perspectives or belief sets may tax their normal working memory capacities, making them sound incoherent.
• Also as opposed to Autistics , who think people do not have an ability to mind-read- as they themselves lack it- the Schizophrenics may be marked by an increased propensity to consider that people can mind read and that too to a very great extent. This may underlie the frequently found delusion in schizophrenia that their thoughts are being broadcasted- that other can read their mind--or at least they want to read their minds using Gizmo's like satellites, headphones etc. The schizophrenic, after all, knows the advantages that can be obtained if one can mind read.
• In its extreme, as the Schizophrenics have too much obsession with mind reading abilities- and the corollary ability to deceive- , they may think that people , in general, are deceptive and manipulators. This may explain why other people would like to insert thoughts or tamper with their thoughts/ memories etc. This may easily give rise to delusions of control.
  
• the ability and propensity to deceive, would also explain the paranoia they feel- after all in their warped world view , all, like them, have immense capacity to deceive/ manipulate- and thus is a potential threat- an untrustable person. This gives rise to the paranoid delusions of schizophrenia.
• Lastly, the obsession of schizophrenics with modeling other minds may lead to multiple personality syndrome (although I know this is not recognized by Psychiatry).

I , like Mary, am not taking sides on whether naive honesty is better or tendency to deceive/camouflage is better; I believe both have their utilities and one should be flexible enough to use both capacities at will. But as we know that much of Human evolution is driven by our capacity to deceive , I would classify schizophrenia as the cost we pay for human Evolution; and Autism as a developmental disorder- We humans are meant to be social and are meant to hide all our raw feelings/ beliefs / thoughts from other persons. Let us deceive, but let us keep that in check- or else be prepared for insanity.

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Answer to the last week's question

Well, the answer is (c) i.e emergence of strong reciprocity is consistent with the observed behavior in the ultimatum game. The evolution of strong reciprocity requires that some people be willing to inflict punishment on the cheaters/free-loafers , even at considerable cost to themselves. This is exactly what people are doing by refusing low offers which they see as an injustices/ unfairness and their behavior of refusing the small offer harms the perpetrator of injustice, even though at cost to themselves.
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Questions make learning easier

It is a well proven fact that answering questions related to the study material you have just learned makes learning easier and more durable. Although I know that readers of this blog are already very learned, without offense to anyone I would like to introduce new feature of this blog: the weekly question. This question will be visible on the left sidebar (at the top) and is actually implemented using the poll feature of the google blogger. This question would be related to the area that I cover in my blog posts for that week.

I encourage all of you to take the poll/answer the question. The correct answer with explanation would be posted , every Friday. This week's question is related to Altruism as I have already covered two studies on that topic.I also encourage readers to contribute questions, that I can put on my blog. My mail id is sandygautamATyahooDOTcom.

Tags: learning

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The Altruistic Mice: how they help a conspecific in a trap.

According to latest research by Claudia Rutte and Michael Taborsky , of the Univ of Berne, Switzerland, rats are capable of generalized reciprocity. The excellent paper is published in the freely available journal PLOS biology, so go have a look.

As per what is know about the evolution of Altruism, it is surmised that co-operation in groups emerges based on four types of reciprocity- direct, indirect, strong and generalized.

In direct reciprocity, one helps another person/animal because the other animal has helped oneself in the past. This requires cognitive capacities to recognize different individuals and require social memory as to which member of the group had helped and which had defected or free loafed. While some animals like the Elephant have good social memories and the ability to remember and recognize different individuals, most animals fall short on these traits.

In indirect reciprocity, one helps another because one has observed the other guy to have helped someone else. This again requires cognitive capacities to recognize and also to remember This is more so based ona reputation system, wherein you start trusting someone more if you observe him doing good deeds. In return you are likely to help the do-gooder , when he is in time of need.

In strong reciprocity, people punish the defectors or free-loafers or non-cooperators. This requires sophisticated cognitive abilities to recognize the defectors and a willingness to undergo cost to oneself while punishing the defector. this too, along with the above two, has rarely been observed in animals apart from humans.

Finally, generalized reciprocity happens when one indulges in good deeds towards a stranger juts based on the fact that one has in the near future received such help from other strangers. con specifics. There are variations on this theme, whereby if people have been put in a good mood (which is a substitute for having received a good deed) they are more likely to indulge in altruistic acts like picking up books dropped by a confederate. This type pf reciprocity does not make very strong cognitive demands as one just has to remember the summary of whether the environment is cooperative or not, to produce the right kind of behavior.

The authors, using some clever experiments demonstrate that rats are capable of generalized reciprocity.

In a nutshell (I'm simplifying a lot here, for details go read the paper), they put two rats in a cage, separated by a transparent partition, such that if one of the rats pulls a string, food would be delivered to the other rat. They ensure that rats learn how to pull the strings and are able to see that their action leads to food for the other rat.



In the experiment, they pair rats such that one rat, who can receive the food but cannot pull the string, is paired with a number of rats who have learned to pull the string. As a aresulkt the rat gets to get a lot of food over consecutive days because of the fact that her partner rat had pulled the string. Thse partner rats ar eall different. In the experimental test condition, the roles are reversed and the focal mice, who had received food due to some stranger rats pulling the strings, is now given an opportunity to pull the string and help a never-before-encountered rat. The result: the mice does pull the string a lot of the times to help the new partner.

In the other experimental condition, the same rat is put in the cage, wherein he can get the food if the second rat pulls the sting. this time too all the rats are new: but sadly for the focal rat, these stranger rats were never trained to pull a string. The result: they never pull the string, so the rat does not receive any food. This is also repeated for a number of days and then the roles are reversed. Now, a new stranger rat is placed in the cage with the focal rat, such that if the focal rat pulls the string, the new stranger rat would get the food. Alas, the lack of pulling of strings by the previous stranger rats makes the focal rat apathetic and she pulls the string less frequently and less enthusiastically. The difference is as huge as 20 % greater pulling when one had received help, compared to when one had not received help.

This seals the argument as per authors, that the rats are indeed capable of generalized reciprocity. They interaction between rats as as between strangers and hence the only reason that explains the difference in string pulling, in received-help versus not-received help is the fact that in former they were in a o-operative environment, while in the latter they were not. thus, their actions were based on generalized help they received from conspecifics and not based on any memories of who helped whom. this to me appears to be breakthrough paper and would lead to a reassessment of how altruism evolved.

The authors also discuss a lot of other possible explanations , and I come satisfied that the generalized reciprocity is the best one.

The author summary is provided below:

The evolution of cooperation is based on four general mechanisms: mutualism, where an action benefits all partners directly; kin selection, where related individuals are supported; “green beard” altruism that is based on a genetic correlation between altruism genes and respective markers; and reciprocal altruism, where helpful acts are contingent upon the likelihood of getting help in return. The latter mechanism is intriguing because it is prone to exploitation. In theory, reciprocal altruism may evolve by direct, indirect, “strong,” and generalized reciprocity. Apart from direct reciprocity, where individuals base their behavior towards a partner on that partner's previous behavior towards themselves, and which works under only highly restrictive conditions, no other mechanism for reciprocity has been demonstrated among conspecifics in nonhuman animals. Here, we tested the propensity of wild-type Norway rats to help unknown conspecifics in response to help received from other unknown partners in an instrumental cooperative task. Anonymous receipt of help increased their propensity to help by more than 20%, revealing that nonhuman animals may indeed show generalized reciprocity. This mechanism causes altruistic behavior by previous social experience irrespective of partner identity. Generalized reciprocity is hence much simpler and therefore more likely to be important in nature than other reciprocity mechanisms.

The NYT also has an article on this and you may like to check that too.

Tags: evolution, moral sense

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