Random Thoughts

Memory, Software, Hardware & Evolution

As a neurologist trying to diagnose Alzheimer’s, amongst the shortcuts one uses are tests for short term memory. One gives a patient unrelated few phrases to remember, like three red roses, one white envelope, 1700 Sansom Street. One repeats this once again, asking the patient to repeat and remember it and then distracts the patient with irrelevant small talk for a few minutes. Then the demand is made for the patient to repeat the series in correct order without prompting or hints. Alzheimer’s patients in the early phase fail to repeat correctly. It is not that memory is the sine qua non of Alzheimer’s disease. Wernicke Korsakoff syndrome, a disease of alcohol abuse or another one like iatrogenic bilateral temporal lobectomy (including the medial part and both hippocampi for controlling seizures) causes loss of ability to retain recently acquired memory and leads to every repeated recent event to be a fresh new occurrence. Interestingly, the destruction of the prefrontal cortex leads to a change of character, personality and judgment as the classic case of Phineas Gage proves. Where is God when you need her?

The point of the above expostulation is to emphasize the need and importance of working memory as any computer buff will understand. Most normal persons can remember up to seven digits forwards and five digits backwards, with concentration. If you ask subjects to remember ten digits forwards or seven digits backwards, you will find that a large majority of the general population fails. There are rare exceptions with photographic memories and those who can calculate the Greek Pi to the thousandth digit without pen or paper or compose complicated music or perform it without great training, but many of those fall into a class called idiot savants. That is their enhanced ability in music, calculation or one specific talent is inevitably associated with lack of achievements in other common faculties like logic, analysis, speech or even more important functions for survival in the world. It is reminiscent of the choice of Achilles, who was offered a short heroic life of brilliant achievement or a long mundane one.

Memory and even more working memory is an important limiting factor in computation as is stoichiometry in certain chemical reactions. Evolution is constantly confronted with this kind of tradeoff. In fruit flies, the workhorse of some important evolutionary studies, genetically modifying the fruit flies for better memory can only be done like Achilles by shortening their life span. Thus a non-challenging environment is more conducive to a longer boring life. Huxley, Darwin’s bulldog, was asked in a debate about God’s partiality to his creation. He quipped that god had an inordinate fondness for beetles, as they constitute the largest number of species of all animals, over 400,000. They are the ultimate scavengers and clean up everything from dung to dead carcasses and only fungi compete with them in public garbage disposal, a civic necessity.

As I have always felt, social animals need to remember who did them a favor and who bore them a grudge. This happens in vampire bats who cannot survive long without a blood meal, and thus beg for it from neighbors after a not uncommon unsuccessful expedition. To remember such favors and reciprocate the bat’s need to remember who obliged and who refused,
 requires a recognition module in the brain, which in bats seems to be on the basis of smell. The combinations of chemicals, which an individual emits is distinctive. This combinatorial mathematics is what lies behind our infinite ability of speech and literature and our wide spectrum immune system, for which the most recent Nobel Prize in Medicine was awarded. In primates, monkeys, apes and us, the recognition goes from smell only, to a combination of smell and vision. In us humans it is mainly vision, but smell is not unimportant as preferences for the smell of underwear of the opposite sex with the right histo-compatibility antigens shows. On a more perverse note that is why incontinent infants and us adults are not offended by the bad smell of our own feces and turned off instantly by the fecal smell of others.

To come back to my title about computing and evolution, I will give you two interesting facts about the behaviors of a rare solitary (non-hive) bee larva and the behavior of an adult female wasp which will confirm that life is a trade off and evolution is a parsimonious arbitrator in this strange game. The information is mainly from Marlene Zuk’s latest book on insects, “Sex On Six Legs” and Richard Dawkins older one, “River Out Of Eden”. While we are all familiar with honey bees, hives and their social lives, there are other bees which are solitary. These lay their eggs in a solitary receptacle and cover the egg with a membrane, after provisioning the egg cavity cell. The mature larva then cuts through the soft covered cell roof to extricate itself and enter the world. Scientists studying this, who were not perverse sadists, installed and additional artificial membrane over the roof of the egg cell. The mature bee larva with its small brain, limited memory and unattended by caring sisters, cut through the natural barrier but failed to use its previously used and adequate cutting mouth parts to cut through an even more flimsy and fragile second artificially erected second barrier to gain freedom and life, because its instinctual mental program lacked the additional line of code and memory telling it to repeat the program, if faced with an identical obstacle.

Evolution in its parsimonious style to get the biggest bang for a buck and not waste its limited repertoire on a highly unlikely natural event, resulted in the perishing of that larva. This kind of problem recurs frequently in nature. The booby, a bird aptly named, lays its eggs on the ground and draws a circle of secretions around the nest. It is not uncommon for a first hatched egg to push its unhatched sibling out of the circle. Take that you Islamic mode of kingdom heritage or primogeniture of the British Crown, just remedied. The parent birds, like programmed Hindus believing in a Lakshman Rekha, then completely ignore their own egg lying outside, and let the potential offspring perish. Equally amazingly, the cuckoo like many contemporary parents in many countries, wants to waste no time in parenting and lays its egg in the nest of another species. It makes sure its egg is laid in the nest of a species whose eggs look like those of the mother cuckoo. There are many variants of mother cuckoos with different colors and speckling of their eggs and like the Jewish custom, the mother’s clan decides the external appearance of a cuckoo’s eggs. What is worrisome and baffling is that the cuckoo egg hatches first and then throws the rest of the eggs out of the nest to monopolize the attention and feeding proclivities of its foster parents. The little nestling because of its species tendencies, extra growth hormone, or whatever, soon is almost the same size as its foster parents and yet when it begs for food, the foster parents enthusiastically feed the crook, which has murdered their real children, with doting parental love.

The final interesting but tragically funny example is that of what is called sphexish behavior. It is an obsessive compulsive behavior which in human beings falls into Obsessive Compulsive Disorder (OCD treated with medications) and requires a circuit involving a part of the basal ganglia of the brain called the caudate nucleus). Wasps are to me the most important animals. They made Darwin loose faith in a benign God and even destroyed Hindu theodicy. Many of them lay their egg in a caterpillar which they have stung and paralyzed. The larva matures, eating the body of the caterpillar from back to front and after consuming the front end of the caterpillar including its primitive brain, emerges as a mature adult. Where is the just or merciful god that most idiots and fools pray to? But this argument is not about justice, mercy or ethics but the constraints of computation.

The experiments were done by Jean-Henri Fabre and repeated by others and confirmed. The female digger wasps stings her prey, paralyzes it and returns to her previously dug burrow. She leaves the stung and paralyzed prey outside the burrow, while she enters, checks and inspects the burrow. The experimenter then moves the paralyzed prey a few inches away from its location. The female wasp comes out of the burrow, searches and relocates the prey and drags it back to the burrow entrance. Only a few seconds earlier, the female wasp had inspected the burrow. But her instinctual program allows no latitude, because of limited working memory and her constrained software. She mechanically leaves the paralyzed prey outside and once again inspects the burrow, before dragging the prey inside and laying her egg. The scientist repeated this forty times before he or she got tired, but the wasp was programmed by its software to repeat the activity ad infinitum and continued to do so because of its limited memory and software as well as hardware.

The point of this essay like in much of finance and ethics is that there is no free ride or lunch and ultimately we have to pay in some form or fashion for everything in time, as even the quantum fluctuations of vacuum insist. So we can run deficits only so long before others stop lending us money and we can only boss over the world so long as the idiots don’t realize that we are bluffing and bankrupt, and even more importantly there is a limit to the gullibility of foolish Americans, which is less than the snake oil selling Republicans and Democrats hope for. And even more importantly, life is a compromise between ought and is.


More by :  Gaurang Bhatt, MD

Top | Random Thoughts

Views: 3359      Comments: 4

Comment Dear Gaurang:

No I haven't read the Korean poet you mention. But I liked the poem you quoted. To be able to abide by its advice (I am not sure if advice is the right word, for art should not advise in my opinion), one needs to be highly intelligent, truly brave and totally uncompromising. Few fall in that category, despite the message that emerges from the poem.

I know I am disappointing you with my lack of acquaintance with the vast literature you quote. Sorry about this. I am still stuck up with the classics I used to read during my college days. :)


03-Nov-2011 01:44 AM

Comment Dear Dipankar, Thanks for your kind appreciation. To me as a neurologist, the brain and speech are very important, but tying them to other things like economics and social behavior is even more fascinating. Evolution has no foresight and no plan, but in its relentless persistence and luxury of time, like the wonderful statement of Krishna in the Gita, "kalo asmi", I am time, the destroyer of everything, but also unmentioned in the Gita, the creator of everything.It destroys and creates what is temporarily and conveniently successful in the present. It realizes like Arrow's theorem, that there is no fair way of determining its outcome or justifying it.
Sadi Carnot was named after the Persian poet Saadi, even though he was French. He like others categorically stated that the third law of thermodynamics can never be violated which in economics, translates as there is no free lunch, there are always externalities. In fact in physics, a science for which economics suffers the same envy that Freud ascribes to women for unmentionable male anatomical parts, there is a thing called Maxwell's Daemon, but I won't bore you or readers with the details, which one can look up on wikipedia, for which I thank evolution, not god. As to nature being brainy or brainless, the parallel economic statement is don't confuse genius with successful money making in a bull market. Nature is amoral, unforgiving and neither kind or merciful and thus the antithesis of those who believe in a god as a fair arbiter, just judge or mercifully tolerant. That is why my favorite poem is---
Out of the night that covers me,
Black as the Pit from pole to pole,
I thank whatever gods may be
For my unconquerable soul.

In the fell clutch of circumstance
I have not winced nor cried aloud,
Under the bludgeonings of chance
My head is bloody, but unbowed.

Beyond this place of wrath and tears
Looms but the horror of the shade,
And yet the menace of the years
Finds, and shall find me, unafraid.

It matters not how strait the gate,
How charged with punishments the scroll,
I am the master of my fate:
I am the captain of my soul.

William Ernest Henley
By the way have you read Ha-Joon Chang the Korean economist at Cambridge?
Gaurang Bhatt

Gaurang Bhatt
01-Nov-2011 12:44 PM

Comment Dear Gaurang:

Thank you for this eye opening article. I have to admit that I am not as well-read as you are, but the points you made are clear enough. The ultimate lesson is what economists call "impossibility of the land of cockaigne". No free lunch in other words.

What's fascinating about your article is that the postulate applies even to as impersonal a process as evolution. I was wondering, as I read through your examples, will a time arrive when the caterpillar will understand the female wasp's will and learn to protect itself? My line of thought follows your statement "So we can run deficits only so long before others stop lending us money and we can only boss over the world so long as the idiots don’t realize that we are bluffing and bankrupt, and even more importantly there is a limit to the gullibility of foolish Americans, which is less than the snake oil selling Republicans and Democrats hope for."

I was quite amazed by the parallel you drew between natural phenomena and social practices. Nature it would seem is not quite a brainless process. And Brain means what we understand it to represent in economics. Or, so I think.

Very illuminating article.

01-Nov-2011 05:02 AM

Comment Darwin's argument against God on the grounds of nature being ‘red in tooth and claw’, exemplified here by the stinging wasp that appears to lack compassion for its victim - yet, in that same act, care for the welfare of its offspring - shows that failing in his reasoning that one can only put down to ignorance, but which in his desire to spite the Almighty, a compulsion exacerbated by the loss of his own young daughter to a terminal illness, he transforms psychologically as an end statement. This is a common flaw in atheists, that because they affirm God doesn't exist with a venomous intent, based on some observed cruelty in nature or human life circumstances, therefore God does not exist; which works to sublime effect in the case of God who is invisible.

GBhatt chimes, ' Where is the just or merciful god that most idiots and fools pray to? ' This is a contradiction in terms, since most implies some don't. But the experience of suffering is the issue. The atheist has no qualms about the very battle in his blood that keeps him alive, and which involves the hunting down and killing of bacteria by white blood cells. Nor is he too upset by the killing and eating of earthworms by songbirds; and progressively up the scale, to the killing of wildebeest by lions. Perhaps, the aspect that begins to disturb him is something being eaten alive - as a pack of wild dogs does lacking the jaw size to administer a stranglehold on its prey: however, the end for the victim is felt to be reasonable. But the idea of a stinging wasp's method described is distinctly abhorrent, because the caterpillar is something being eaten alive over a protracted period of time. Arbitrarily, this is adjudged a heinous method devised, of course, by God. Here the atheist comes into his own: therefore God is cruel, therefore God does not exist.

The issue is the experience of suffering. When you experience suffering as a human being, you always refer to it in personal terms: 'my leg hurts' or 'I am feeling cold'. Suffering is always a 'my' realisation, whence it is experienced. If there is no my realisation, as when a baby, when my realisation is not developed, although pain is felt, from whatever source, there is no personal realisation as would enable us to recall it. The lack of my realisation in the whole gamut of living forms, from amoeba to caterpillars to gorillas, means that suffering is not realised as a my realisation; consequently, it is true to say that any life form lacking 'my realisation' cannot suffer personally, except that it is projected to by a human observer who endows it with a my realisation it quite plainly lacks.

01-Nov-2011 00:11 AM

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