Shmoos and Free Goods

A week or so ago there was a comic in the local paper asking how you get Kentucky Blue Grass. The answer was to mow your lawn while the Smurfs were having a picnic.

That morning, the leader of our water aerobics class asked if anyone remembered the name of the characters shaped like bowling pins who were in Al Capp's Li'l Abner strip. Her husband, after reading the Kentucky Blue Grass comic, thought they were called Smurfs, but she didn't think so.

Most of us in the pool remembered the characters but I was the only one who (and failrly rapidly) came up with the name "Shmoos". Since I am losing my mind (among other things) I was quite proud of my memory feat in this case. Especially so when several people I asked about it were unable to remember the name (the best one came up with "Igoos").

I looked them up in Wikipedia and was amazed at the philosophical content of the Shmoo characters. When I was a kid I just read the comic and laughed, but Shmoos represent some deep satirical ideas indeed! As well as the economic concept of a free good.

Here are some of the more interesting ones from Wikipedia. I recommend you read them all at the above link.

They consume no resources other than air and reproduce prolifically. The closest natural thing that does anything like that would be wild fruit trees and edible berry bushes. I guess we could include edible fish and land animals, but these usually require quite a bit of work to catch.

They are edible and anxious to please. The Li'l Abner comic panels [hold CTRL and press + to make images larger] show how a shmoo simply "draps daid - outa sheer joy" if a person looks at them hungrily! Raw, they taste like oysters, but cooked they taste like chicken (if fried), steak (if broiled), pork (if roasted), or catfish (if baked).

Shmoos sustain themselves and volunteer to be cooked and eaten. That put lots of farmers and hunters and grocers out of business! (So you see the mixed blessing of a free good.)

"They also produce eggs (neatly packaged), milk (bottled grade-A), and butter — no churning required. Their pelts make perfect bootleather or house timber, depending on how thick you slice it.

"They have no bones, so there's absolutely no waste. Their eyes make the best suspender buttons, and their whiskers make perfect toothpicks. In short, they are simply the perfect ideal of a subsistence agricultural herd animal. "

Shmoo are also entertaining. They put on "shmoosical comedies" that put actors and movie-makers and TV stations out of business. And, like the mythical "snipe", some especially tasty shmoos play hard to get. It is entertaining to go out at night with a flashlight and a large bag and a stick and catch them.

No need for humans to work anymore. So, it seems, with shooos around and procreating rapidly, humans would, in effect, be back in paradise before Adam and Eve sinned. That would put our political leaders and corporate execs and labor unions out of business as well.

In the Li'l Abner comic, the shmoos are hunted to extinction, by "shmooicide squads".
ORIGIN OF THE IDEA
All Capp explained how he got the idea for shmoos in a Cosmo piece in 1949:

I was driving from New York City to my farm in New Hampshire. The top of my car was down, and on either side of me I could see the lush and lovely New England countryside… It was the good earth at its generous summertime best, offering gifts to all.
And the thought that came to me was this: Here we have this great and good and generous thing — the Earth. It's eager to give us everything we need. All we have to do is just let it alone, just be happy with it.
Cartoonists don't think like people. They think in pictures. Little pictures that will fit into a comic strip. And so, in my mind, I reduced the earth… down to the size of a small critter that would fit into the Li'l Abner strip — and it came out a Shmoo… I didn't have any message — except that it's good to be alive.
The Shmoo didn't have any social significance; it is simply a juicy li'l critter that gives milk and lays eggs… When you look at one as though you'd like to eat it, it dies of sheer ecstasy. And if one really loves you, it'll lay you a cheesecake — although this is quite a strain on its li'l innards…
I thought it was a perfectly ordinary little story, but when it appeared in newspapers, all hell broke loose! Life, in an editorial, hailed the Shmoo as the very symbol and spirit of free enterprise. Time said I'd invented a new era of enlightened management-employee relationship, (they called it Capp-italism.) The Daily Worker cussed me out as a Tool of the Bosses, and denounced the Shmoo as the Opium of the Masses...

They say "there is no such thing as a free lunch", but, if there was, would it be good for humanity?

Ira Glickstein

Fond Memories of Popular Science Magazine

Thanks to Google, the Popular Science magazine archives are available free! (Hat tip to WattsUpWithThat for the alert.)

The cover of the July 1977 issue is shown because it includes a wonderful piece. Click here to see it!

What makes this item so great? Well, I wrote it and it shows our three daughters, Rena, Lisa, and Sara, with their stuffed animals, on a bed/bench I designed and built for our van when we did some camping.

It also includes a photo of me when I was about half my current age and a nice do-it-yourself construction diagram. (The piece includes some other photos, not shown here.)

[For larger images, either hold CTRL and press + or click on image.]









You can page through any issue and see not only the stories but also the adverts, which are often more interesting.

Ira Glickstein

Peirce, Semiotics and Sports

[From Joel] I tried to follow what Howard was saying [First comment on Million Monkeys ...] by looking up Peirce [on Wikipedia]. I became lost in the jargon. However, I did get something out of it, because the president of Harvard apparently blocked any role for Peirce at Harvard. I checked out Eliot to see if I could find out why. Along the way I found this interesting statement from Eliot's bio in wikipedia. Did Eliot have a point? Do some sports degrade character?

Eliot's opposition to football and other sports
During his tenure, Eliot opposed football and tried unsuccessfully to abolish the game at Harvard. In 1905, The New York Times reported that he called it "a fight whose strategy and ethics are those of war", that violation of rules cannot be prevented, that "the weaker man is considered the legitimate prey of the stronger" and that "no sport is wholesome in which ungenerous or mean acts which easily escape detection contribute to victory."[citation needed]

He also made public objections to baseball, basketball, and hockey. He was quoted as saying that Rowing and Tennis were the only clean sports.

Eliot once said, "Well, this year I'm told the team did well because one pitcher had a fine curve ball. I understand that a curve ball is thrown with a deliberate attempt to deceive. Surely this is not an ability we should want to foster at Harvard."

Time, the flexible dimension

[From Joel] I was lying in bed this morning noting that the clock somehow had not sprung forward. I lay there thinking about time and in particular about waiting. At the moment, I'm waiting for some oral surgery to heal and anticipating the moment when I can eat some serious solid food. There's nothing like waiting for a wound to heal to turn your attention to how much of our lives are spent in anticipation of a future event.

Generally speaking, I try to avoid waiting. If there's a long line to go to a movie or participate in a buffet, I'll forgo the film or go hungry before I'll wait on line. But, waiting to heal is not something voluntary and sometimes the discomfort doesn't let you do other things that would normally let you ignore the wait. There seem to be at least two approaches to such a situation. Some people "bitch and moan" to pass the time while others just curl into a ball and make the world go away.

We have various interesting expressions concerning waiting. We sometimes call a hobby or a sport like golf a "pastime" from the French "passe temps," literally "pass the time way." Obviously, pastimes are diversions (another French word) which distract the mind from focusing on what seems like the interminable wait until we achieve our end state. The trouble is that sometimes the "diversion" is just that. It relieves the pain of waiting but also postpones or even prevents the achievement of the goal. Beer parties keep one's mind off waiting to complete one's education, but graduation never arrives for many who overindulge. We use the expressions "time marches on" and "time and tide wait for no man." Humans, like most animals and plants, have biological rhythms, known as circadian rhythms, which are controlled by a biological clock and work on a daily time scale. These affect body temperature, alertness, appetite, hormone secretion etc. as well as sleep timing. Our illusion of time slowing down or speeding up in emergencies is at conflict with our biological clock. Or is it?

Toyota Runaway = "Creative Destruction"

[Update 13 Mar 2010. In my original posting I wrote: "...I believe some of the reports are 'copy cats' looking for publicity." Well, the incident pictured above may be one such Copy Cat.] As those who follow this Blog may know, my wife and I have been driving a 2004 Toyota Prius hybrid -our only car- and have been very happy with it. So, quite naturally, we have been following the controversy about runaway Toyotas very closely.

The photo above shows a runaway Prius. On 8 March, this car raced up to 90 mph on a California freeway when the accelerator pedal apparently stuck. The terrified driver tried to slow the car using the brakes but they were ineffective.

He called 911 and a CHP trooper came alongside. Using his bullhorn, he told the driver to stand on the brake pedal and also apply the emergency brakes. Finally, with both brakes on and a steep uphill section of roadway, the car slowed sufficiently for the driver to turn off the ignition and coast to a safe stop.

TOYOTA'S INEFECTIVE RESPONSE

When runaway incidents began being reported by the press and TV, Toyota claimed that the runaway incidents were due to improperly installed floor mats that jammed the pedal in the full-on position. They fixed that by asking users to secure floor mats properly and not to use double mats.

Then, they admitted that the innards of some accelerator pedals could corrode and stick in the full-on position. They fixed that by installing a metal shim.

Nevertheless, the incidents keep occurring. I believe some of the reports are "copy cats" looking for publicity. Some are from people who mistakenly pressed the accelerator instead of the brakes and are falsely trying to shift the blame to a hardware defect. However, many, if not most, are genuine failures and not in any way the fault of the drivers.

WHY DIDN'T TOYOTA APPLY A SOFTWARE FIX?

When the news first came out a month or so ago, my first reaction was that -whatever the actual cause- Toyota should immediately install a software over-ride that would disconnect or limit the accelerator signal, or shift the car into neutral, if the brakes were applied while the accelerator was on.

Here is the technical detail for the CTS pedal used by Toyota. The accelerator pedal sends an analog voltage to the onboard computer. The brakes also send a signal to the computer. Toyota has the ability to update the computer software. Therefore, a software fix could limit the accelerator signal to some minimal value whenever the brake is on, perhaps by shifting to neutral. (The engine should not be shut down because that would disable the power brakes and power steering.)

Even if, as Toyota still claims, the problem is strictly mechanical, a software over-ride, to prevent acceleration when the brakes are applied, would prevent most of the accidents we have read about.

AUTOMOTIVE SOFTWARE HAS A LONG WAY TO GO

Before we retired, my wife and I worked on aircraft electronics systems and software. We currently teach online graduate courses on those subjects for the University of Maryland University College. Aircraft systems and software are developed, tested, verified and validated in a very controlled environment. Our methodology is based on "lessons learned" over the past few decades. Automotive engineers have only been in the software game for about a decade. They could learn alot from us.

It is clear to me that either the Toyota engineers and software developers are incompetent, or -more likely in my opinion- their management has restricted their efforts either due to cost concerns or legal liability, or both.

While I have no inside knowledge, I cannot believe that no engineer at Toyota ever suggested a software over-ride when brakes are applied. I can imagine some Toyota engineers, when the runaway acceleration incidents were first reported to Toyota several years ago, suggesting a software patch to over-ride whatever mechanical failures were the actual cause. "No," I can hear some anal manager say, "If we fix the software that will be costly and will imply that we are legally liable for not having the brake over-ride in the original design." I can imagine a room full of managers and lawyers nodding their heads like so many bobble-dolls!

HASN'T ANYONE HEARD OF BASIC ERROR CHECKING?

I think the press has been pretty responsible, although they have been taken in both by Toyota appologists and some publicity-seeking "experts". Brian Ross (ABC News) has done a good job but I believe he was a bit off when he rode along with a college prof who shorted the accelerator pedal wires. That made the car accelerate out of control, as Brian Ross stood on the brakes. The prof then showed that the computer in the car did not display any error codes.

A week later, Toyota engineers did the same wire-shorting experiment on several cars from different manufacturers, and they too did not display any error codes. Toyota did the demo to show they were blameless. But, all it indicates to me is that the other automobile manufacturers are also incompetent!

I know exactly what the prof did. There are three wires to the pedal: 1) Ground, 2) Vin, (voltage input, probably 12 volts DC) and 3) Vout (voltage output that varies from zero volts to 92% (+/- 3%) of Vin as the accellerator pedal is pushed all the way down). If, due to loose insulation (or the actions of the prof), Vin (wire 2) happens to short to Vout wire (wire 3), the computer will get a Vout equal to 100% of Vin and will interpret it as a signal that the accelerator is pushed all the way down.

If the pedal and software had been designed the way aircraft electronics is designed, the computer software would recognize that Vout was 100% of Vin, exceeding the limit of 95%, and would have set an error code. Beyond setting an error code, had the system been designed to aircraft electronics standards, exceeding 95% of Vin would have been recognized as shorted wiring and should have initiated speed limiting.

Apparently, the automotive system and software engineers have not implemented even the most basic error checking! This applies not only to Toyota but also the other manufacturers whose cars were part of the Toyota wire-shorting demo!

WHERE WERE THE REGULATORS? THE COURTS?

Toyota, the world's leading auto company, has turned out defective products that killed some customers and endangered others. Until a week ago, they did not even let the National Highway Transportation Administration (NHTSA) have access to their internal "black box" codes. NHTSA seems to have gone along with Toyota's arrogance. The regulators were either "asleep at the switch", or incompetent, or in the pocket of the industry they were regulating, or all three!

Based on the Toyota wire shorting demo, the other auto companies are nearly as incompetent. (To their credit, however, the other companies do make their "blackbox" error code translator units available to regulators and dealerships.)

According to press reports, a former Toyota liability defense lawyer, who said he alerted the company to systemic problems several years ago, and who has the emails to prove it, has recently come forward. According to him, Toyota had a "book of knowledge" that detailed known design defects. Company lawyers used that information as part of the decision process of whether to fight a lawsuit or settle. Where were the courts?

Of course, now that the facts are coming out, NHTSA and the courts will take action. Liability lawyers on both sides will get rich and some victims will be compensated.

"CREATIVE DESTRUCTION"

The term "Creative Destruction" applies here. In its normal meaning, it signifies the way, under capitalism, new technology, products, and services push out the old. As an inevitable part of the process, some backward industries and companies go bankrupt, stockholders lose their investments, employees lose their jobs, and entire communities may fall into poverty. That is the "destructive" part. At the same time, some pioneering industries and forward-looking companies rise and create newer and often better jobs, investors make money, and entire communities enjoy prosperity. That is the "creative" part.

I'd like to apply the term to the "Creative Destruction" of the now tarnished Toyota brand. It is a once valued brand that has been devalued by their coverup of known defective designs and failure to fix them promptly. They would rather stonewall and fight in court than do the right thing. I believe this will sour most consumers on the Toyota brand.

My wife and I had planned to replace our 2004 Prius with a newer plug-in Prius in a couple years. No more! I doubt we will ever buy a Prius again.

That is a pity because we have been very happy with our Prius and love their dealership in Ocala, FL. That dealership may be forced out of business and some Toyota employees will lose their jobs and stockholders will lose their investments. That is the "destructive" part.

I only wish the regulators at NHTSA and the lawyers and the court system that failed in this case would also go out of business. But no, perversely they will be rewarded with more power and more court cases.

The "creative" part is the business that will flow to Ford and other auto manufacturers who have behaved better. I am following the Ford Fusion and we may purchase their plug-in electric-only version that is expected to come out in a couple of years. (Besides, we have owned Ford stock for many years.)

MEANWHILE WE ARE DRIVING OUR TOYOTA PRIUS GINGERLY

Today, for the first time, I got up the courage to practice stopping the car by shifting to neutral. With my foot on the accelerator, I pushed the gear shift to the left. I had to hold it for about a second, but then I could feel the accelerator disconnect and the car coasted to a lower speed.

From reading news stories, I now know that the ON/OFF button must be held for three seconds to take effect. In case shift to neutral does not work, that is how I will stop my Prius if it happens to run away.

[Update 13 Mar 2010. The person involved in the runaway incident reported above seems to have some baggage. He apparently owes lots of money. Parts of his story do not ring true. The Prius he was driving supposedly has the brake over-ride software I described above. This raises two quesions: 1) If brake over-ride has been available on Prius cars for so long, why isn't it on all Toyotas? 2) If the car involved in this incident had brake over-ride, did it fail or did the driver purposely work around it? Assuming the car actially had brake over-ride and it was working, the driver would have had to alternately press the accelerator to speed up, then release it and press the brakes to get them to heat up and smoke as reported, and so on. According to the 911 tape, the 911 agent told him to put the car into neutral but he refused, saying he feared it would cause the car to flip.

According to Toyota from FAQ issued 3 Feb 2010: "the Prius, and all hybrids for that matter, already have a version of the override system. The override system will be standard by the end of 2010." Thus, the runaway problem does not exist for our Prius nor any other hybrid. The brake override will be standard on all newly-manufactured Toyota automobiles after 2010. According to this, the brake override will be added to previous model years of some non-hybrid Toyotas back to 2005 .]

Ira Glickstein

Million Monkeys on a Million Typewriters and Other Failed Experiments

Many, many years ago I came across a most compelling thought experiment (you must have heard it as well.) It goes like this:

If a million monkeys typed on a million typewriters for a million years, one of them would be sure to type out one of Shakespeare's plays.

Of course, you would need a million English Teachers to read all the typed material, as well as thousands of zookeepers to tend to the monkeys - but that would create jobs. Perhaps this grand experiment could be funded by the Jobs Bill. It would surely stimulate the economy and, we could sell the poems, short stories, novels, and other works created by the monkeys. SO, it would be revenue-neutral.

MY EXPERIMENT

I decided to do the experiment using the latest in computer tools, my laptop plus an Excel spreadsheet. You can download the Excel spreadsheet here. Every time you press the F9 key on your PC keyboard, a "monkey" produces a paragraph.

Now, to give the "monkey" all possible advantages, I created a special keyboard that has more "E" keys and "A" keys and so on, according to their frequency in English text. The keyboards have no numbers or special characters. Half the monkeys are working on keyboards with no punctuation, since any good English teacher can visually pick words out of a stream of characters and phrases and sentences out of a stream of words. The other half have keyboards that include some comma and period keys.

Below is the BEST example I could find in quite a few tries. Words are outlined in red. [Click CTRL + repeatedly for larger view. CTRL - for smaller view.]

I really expected to see more words and some phrases and perhaps a sentence or two. NADA!

Download the Excel spreadsheet here.and try it yourself! Perhaps your "monkeys" will have better luck.

WHY DID IT FAIL?

This is a good example of how the most compelling thought experiments can mislead even the most intelligent among us. Indeed, it would probably take an overly intelligent person to buy into this concept.

It turns out that Wikipedia has the explanation for the failure of our expectations:

"... If there are as many monkeys as there are particles in the observable universe (10^80), and each types 1,000 keystrokes per second for 100 times the life of the universe (10^20 seconds), the probability of the monkeys replicating even a short book is nearly zero."

THE "PARTS" PROBLEM

One of the many valuable things I learned about from Prof. Howard Pattee, when he was my teacher and Chairman of my PhD Committee, was the "parts problem".

For a partially random process of assembly to result in any thing of value, the parts must be in the right proportion to the thing you will produce. In the case of the Million Monkeys, the parts are random letters and we are looking for a book-length result (a Shakespeare play).

All we got were a few English words sprinkled among lots of gibberish.

Had we started with words as the parts, and had they been in proportion to their frquency in the English language, we would have obtained better results.

For example, there are about 10,000 English words that constitute over 99% of all English writing. Say we had a "keyboard" with 100,000 keys, with each word having as many keys as justified by its frequency in the English language. A "monkey" typing thousands of keystrokes on such a "keyboard" would be quite likely to produce a number of grammatical phrases and even sentences, and perhaps several meaningful sentences. The "monkey" might even produce a unique, original thought.

We'd be still further ahead if we used the computer to impose grammatical structure. The "monkey" would have three "keyboards". the first would have keys for SUBJECT, the second for VERB, and the third for OBJECT. Thus, each sentence would be of the form: "The BOY LOVES the GIRL" or "JACK HITS the BALL", etc. Of course, most sentences while gramatical, would not be meaningful, "The GIRL HITS the BEDROOM" or "The GRAPEFRUIT LOVES the SHOES", etc.

Of course, this system would create only the simplest of simple sentences.

For more natural sentence structure, we could use larger parts, such as phrases. Or perhaps ready-made sentences with fill-in-the-blanks like those we used to use as party games.

Like many things in the natural and artificial world, written language is a hierarchical set of structures. English consists of letter characters that, when taken in groups, form words of up to several letters. (But, you can't just take random letters and get a word. You need a proper ordering of vowels and consonants, etc.) At the next level up are simple and compound sentences made up of groups of words. (But, that cannot be random either, you need subject, verb, object substructures). At the next level paragraphs, then sections, then chapters, etc.

HOW THE GENETIC SYSTEM SOLVES THE "PARTS" PROBLEM

When we decode the genome of some animal we express it in a series of four nucleotides A, T, G, C. Each of these letters stand for a molecular assemblage containing a dozen or two atoms. Sequences of these letters (in the "genotype") code for the generation of various amino acids and groups of amino acids code for proteins. Combinations of proteins constitute what we call "genes" that code for physical characteristics (in the "phenotype").

The genetic system long ago settled on a really neat hierarchcal system where the lowest levels are very stable and most are common between different species. When DNA is copied, there are multiple instances of codes for the really important proteins. There are correction mechanisms for many types of mutations (copying errors) . The same is true at the next level, which we call "genes", and the level above that of multiple genes that work in concert, etc.

Notice how, in the genetic system that has been evolving over the past three or four billion years, the "parts" at each level are appropriately sized for their jobs. (My Optimal Span Hypothesis  http://iraknol.wordpress.com/article/optimal-span-3ncxde0rz8dtk-2/ ) provides a basis, founded in well-established information theory, for how hierarchical systems are most effectively organized.)

A TEXT GENERATOR THAT REALLY WORKS

Here are excerpts from a "Post-Modernist" academic paper I just generated:

Reinventing Modernism: Neosemioticist objectivism, capitalism and Derridaist reading
Andreas Porter
Department of Ontology, Massachusetts Institute of Technology

1. Derridaist reading and patriarchial conceptualismIn the works of Burroughs, a predominant concept is the distinction between figure and ground. Therefore, subtextual dialectic theory states that truth is unattainable.

The main theme of the works of Burroughs is the failure, and hence the futility, of precapitalist sexuality. In a sense, several discourses concerning patriarchial conceptualism may be discovered.

If Batailleist `powerful communication’ holds, we have to choose between subtextual dialectic theory and cultural narrative. But the creation/destruction distinction prevalent in Burroughs’s The Last Words of Dutch Schultz emerges again in Naked Lunch.

2. Expressions of dialecticThe characteristic theme of Hamburger’s[1] analysis ...

1. Hamburger, O. ed. (1972) Subtextual dialectic theory and Derridaist reading. University of California Press ...

The above "scholarly paper" and as many as you'd want to see like it, are available at Communications from Elsewhere.

The computer program behind this feat starts with parts that are very large. Indeed, each paper has a Title, Authors, Sections (with paragraphs and sentences), and Citations. Each of these has a set form. The only randomness is the insertion of words from certain lists into specified blanks. The results are quite compelling.

Indeed, if you gave one of these papers to a group of intelligent people who were not experts in post-modernism, many would accept them as peer-reviewed material. AND a Post-Modernist Journal might peer-review and accept the paper for publication! (See Sokal Affair)

Ira Glickstein

Wasted Funds??

Another way we can stretch our health care resources is to do away with the funding of useless research. This morning I heard a news report about a study linking "purpose in life" and Alzheimer's. Out of curiosity I looked up what I could about the study. I googled one of the authors (Patricia Boyle) and found a significant number of statistical studies have been funded by NIH which investigate various psychosomatic risk factors. Could we find better medical uses for the the allocated funds? Is this information of any value? -Joel

[The following is from: http://archpsyc.ama-assn.org/cgi/content/short/67/3/304]

Effect of a Purpose in Life on Risk of Incident Alzheimer Disease and Mild Cognitive Impairment in Community-Dwelling Older Persons

Patricia A. Boyle, PhD; Aron S. Buchman, MD; Lisa L. Barnes, PhD; David A. Bennett, MD

Arch Gen Psychiatry. 2010;67(3):304-310.

Context Emerging data suggest that psychological and experiential factors are associated with risk of Alzheimer disease (AD), but the association of purpose in life with incident AD is unknown.

Objective To test the hypothesis that greater purpose in life is associated with a reduced risk of AD.

Design Prospective, longitudinal epidemiologic study of aging.

Setting Senior housing facilities and residences across the greater Chicago metropolitan area.

Participants More than 900 community-dwelling older persons without dementia from the Rush Memory and Aging Project.

Main Outcome Measures Participants underwent baseline evaluations of purpose in life and up to 7 years of detailed annual follow-up clinical evaluations to document incident AD. In subsequent analyses, we examined the association of purpose in life with the precursor to AD, mild cognitive impairment (MCI), and the rate of change in cognitive function.

Results During up to 7 years of follow-up (mean, 4.0 years), 155 of 951 persons (16.3%) developed AD. In a proportional hazards model adjusted for age, sex, and education, greater purpose in life was associated with a substantially reduced risk of AD (hazard ratio, 0.48; 95% confidence interval, 0.33-0.69; P < .001). Thus, a person with a high score on the purpose in life measure (score = 4.2, 90th percentile) was approximately 2.4 times more likely to remain free of AD than was a person with a low score (score = 3.0, 10th percentile). This association did not vary along demographic lines and persisted after the addition of terms for depressive symptoms, neuroticism, social network size, and number of chronic medical conditions. In subsequent models, purpose in life also was associated with a reduced risk of MCI (hazard ratio, 0.71; 95% confidence interval, 0.53-0.95; P = .02) and a slower rate of cognitive decline (mean [SE] global cognition estimate, 0.03 [0.01], P < .01).

Conclusion Greater purpose in life is associated with a reduced risk of AD and MCI in community-dwelling older persons.

Author Affiliations: Rush Alzheimer's Disease Center (Drs Boyle, Buchman, Barnes, and Bennett) and Departments of Behavioral Sciences (Drs Boyle and Barnes) and Neurological Sciences (Drs Buchman, Barnes, and Bennett), Rush University Medical Center, Chicago, Illinois.