Working on a book formatted with GNU Texinfo, I ran into a mysterious error when processing the Texinfo source through TeX (via texi2pdf):

(Variable Index) [145] (Concept Index) [146] (./c.cps
./c.cps:1: Extra }, or forgotten \endgroup.
l.1 , 145}

I saw no related error or warning out of Makeinfo, and TeX was unhelpfully not saying anything about which Texinfo source line the error was coming from. Other clues suggested that the error has to do with indexing, and that it has to do with an index entry pointing to page 145 or maybe 146.

Looking at the PDF output, I backtracked to the relevant portion of the Texinfo source, and saw something like this:

@cindex function pointers
@cindex

A normal-looking index entry followed by an empty index entry! I removed the empty index entry and reran TeX; all was fine.

Evidently empty index entries are not handled well in Texinfo or texi2pdf or TeX or wherever the actual failing is coming from. A more helpful error message would be nice, but in the meantime, remember to avoid blank index entries!

This past spring I read Seymour Papert’s Mindstorms as part of the MIT Media Lab Learning Creative Learning course. Having been delighted with that book, I just finished reading Papert’s follow-up book, The Children’s Machine (Rethinking School in the Age of the Computer).

Published in 1993, this book comes across as technologically more modern than 1980′s Mindstorms, though still obviously dated. For me, it is dated in an especially nostalgic way, as it was around the late 1980s / early 1990s that I was first learning about computer programming, and I can personally identify with some of the stories and concepts that Papert discusses here.

Broadly, this book might be viewed as a refinement of Mindstorms, whereby Papert had over a decade of additional experience and observations with which to form stronger, clearer opinions and gather more data and anecdotes. But while Mindstorms seemed to focus more on the specific idea of creating virtual educational worlds on the computer in which students could more easily learn abstract ideas, the present book steps back even further to look at understanding learning itself better.

Papert advances the term mathetics for describing the study of learning, as opposed to pedagogy, the study of teaching. Are there methods we can use ourselves, or encourage in students, to identify what needs to be done on the learner’s side in order to learn better? To rely on “being taught” without exerting enough effort on “learning” puts things out of balance.

This concept of mathetics is woven into accounts of using computers to improve how learning takes place, especially through creative learning techniques of building virtual things with computers, and through the notion of learning a concept better by teaching it to the computer via programming. For example, we read some stories about the development and usage of the Logo programming language and the Turtle programming system that was developed with it, and how this grew into a form of cybernetics controlling robotic Legos. Here’s a short example, in this instance about using Mitch Resnick’s multi-turtle Logo variant, *Logo:

Two high school students who had recently received their driver’s licenses decided to use *Logo to show cars moving on a highway. The students started by creating several dozen turtles, each representing a car. The program consisted of two simple rules. If a car sensed another car ahead of it, it slowed down. If it didn’t sense another car, it speeded up. With this simple program the students did not expect much to happen, but when they ran it, the cars bunched into a realistic-looking traffic jam. … It is worth noting that the students appreciated the self-organizing nature of the traffic jam only because they had written the programs themselves. Had they been using a packaged simulation, they would have had no way of knowing the elegant simplicity of the programs underlying the jam.

The front cover quotes School Library Journal as saying, “Educators with a vested interest in the status quo will hate this book. It is about their demise.” Indeed, there are numerous points brought up for consideration about how the educational system could be improved, including scathing criticism of attempts to nationally standardize education and judge student development based on standardized tests. Along these lines, Papert poses an interesting query for educational administrators:

[O]n my reckoning, the fraction of human knowledge that is in the [school] curriculum is well under a millionth and diminishing fast. I simply cannot escape from the question: Why that millionth in particular?

If you must limit yourself to reading only one Papert book, Mindstorms came across to me as more fresh and exciting, but the creative learning aficionado will get valuable insight from reading both. The paperback edition is available at Amazon. No electronic edition appears to be available.

I just finished reading Privacy on the Line: The Politics of Wiretapping and Encryption. With all of the information being revealed and confirmed recently about United States government surveillance on personal communications, I wanted to be more educated on the issues.

Going about our day-to-day lives, how much privacy do we really have? The authors explain:

From video cameras that record our entries into shops and buildings to supermarket checkout tapes that list every container of milk and package of cigarettes we buy, privacy is elusive in modern society. There are records of what we do, with whom we associate, where we go. Insurance companies know who our spouses are, how many children we have, how often we have our teeth cleaned. The increasing amount of transactional information — the electronic record of when you left the parking lot, the supermarket’s record of your purchase — leaves a very large public footprint, and presents a far more detailed portrait of the individual than those recorded at any time in the past. Furthermore, information about individuals is no longer under control of the person to whom the information pertains; such loss of control is a loss of privacy.

What about U.S. government surveillance? The authors provide chapters of fascinating details, including:

Beginning in 1940 and continuing until 1973, FBI and CIA agents read the private mail of thousands of citizens. … Without warrants and without congressional or clear presidential authority, intelligence agents opened and perused the mail of private citizens, senators, congressmen, journalists, businessmen, and even a presidential candidate.

Numerous other examples include the FBI’s excessive surveillance of Martin Luther King, Jr., authorized wiretaps being left activated beyond their official period of use, the FBI seeking information on who has borrowed unclassified scientific and technological books from public libraries for the purpose of identifying possible Russian spies, and more. In some cases, the FBI admitted that their surveillance tactics exceeded legal limits; in other cases, evidence against the FBI magically disappeared. Either way, it appears that if government agents wish to violate the law when it comes to surveillance, there is little (if any) actual oversight of their actions.

While government surveillance has been expanding by leaps and bounds, the authors make the case that not only is the huge amount of surveillance not commensurate with the relatively small amount of criminal or violent activity that it helps prevent, but even in situations where surveillance has been credited with helping to prevent undesirable outcomes, the surveillance tactics may not have been necessary.

It is important to apply common sense to the issue of terrorist investigations and to think clearly about which acts can be prevented and which cannot (Heynmann 1998, pp. xxi-xxiii). Timothy McVeigh’s attack on the federal office building in Oklahoma City was the work of a group of three people. … Unless the United States moves to a surveillance society on the scale of the former East Germany, the country will never be able to protect itself fully against attacks by “lone warriors” such as McVeigh.

To be clear, the authors do not claim that surveillance is useless against criminal or terrorist behavior; rather, it is of limited usefulness, and we need to appropriately balance legitimate surveillance needs with the privacy of the citizens.

On a more practical level, should we use encryption to protect the privacy of our emails and other communications? The authors seem generally in favor of it, but also warn us that:

One strategy followed by many pieces of intercept equipment should be a caution to anyone using cryptography: if an intercepted message is found to be encrypted, it is automatically recorded.

Since most emails are presently not encrypted, the very act of encrypting yours may draw attention to yourself. But at the same time,

as the use of cryptography increases, the privacy of everyone’s traffic benefits.

In light of the recent disclosures about the NSA’s methods of circumventing encryption, the book’s concluding chapter offers some especially interesting thoughts:

By building the machinery for surveillance into the US communication system, we overcome the largest barrier to becoming a surveillance society on a possibly unprecedented scale.

Once past that barrier (a place we may already have arrived at), it is much easier for laws and policies to fall into place in accordance with what is technologically possible.

This book is tightly packed with well-sourced information; I’ve only hit a few highlights here. It is available both in printed form and for Amazon Kindle, but if you don’t want the NSA to know that you bought this book, and if you don’t want Amazon to know how you read it, you might want to pay cash at the MIT Press Bookstore in Cambridge…

I just finished reading Paul Bloom’s How Children Learn the Meanings of Words. A reader of this book might expect to come away being able to answer the question, “how do children learn the meanings of words?” but in the final chapter, Dr. Bloom states that nobody knows how children learn the meanings of words! What, then, can we hope to gain by reading this book?

In claiming that nobody knows how children learn the meanings of words, the author is affirming what the previous ten chapters implied: this is complicated stuff, and state of the art research is just scratching the surface. The book covers a variety of subtopics related to word learning, including how children learn nouns, and pronouns, and numbers, and how they differentiate between naming things and naming representations of things, and how their words and their thoughts interrelate. But since what is known of these topics is still in its infancy, with much room for debate, rather than pontificating unsubstantiated opinions as facts, the author spends most of the book summarizing results from years of experimental linguistic research.

The first chapter kicks things off with some fun, considering how children learn what exactly the word “rabbit” refers to. If a child sees a grey rabbit running through the yard, and an adult points to it and says, “Rabbit!”, does the child understand that the word “rabbit” refers to a kind of animal? Or does the child believe that the word refers to that one particular animal (perhaps it is named “Rabbit”)? Or does the word refer only to grey rabbits, but not brown ones? Or to all mammals in general? Or to only the ears of the rabbit? Or to the tail? Or to “all and sundry undetached parts of rabbits”? Such questioning can carry us down the path of the ridiculous, but they are fair questions if we want to understand how words are learned.

My favorite excerpt from the book has nothing at all to do with linguistics, but was mentioned in passing as it pertains to cognition in general:

Adults are often oblivious to dramatic changes across a visual scene, even for objects that are the direct focus of attention, a phenomenon known as change blindness. In one striking demonstration of this, an experimenter started a conversation with a pedestrian and then, during a distraction, was surreptitiously replaced by a different experimenter. Only about half of the pedestrians noticed the change (Simons & Levin, 1998).

We also see a good rebuttal to the ever-popular Sapir-Whorf hypothesis, including a parody (originally published by Gregory Murphy) showcasing circular reasoning in the hypothesis:

Whorfian: Eskimos are greatly influenced by their language in their perception of snow. For example, they have N words for snow [N varies widely; see Pullum, 1991], whereas English only has one, snow. Having all these different words makes them think of snow very differently than, say, Americans do.

Skeptic: How do you know they think of snow differently?

Whorfian: Look at all the words they have for it! N of them!

Never content to assume a research experiment—even his own—has led to the one true answer, Dr. Bloom compares and contrasts the various experiments, pointing out both inadequacies and strengths, gently prodding the reader toward what he believes are the most plausible conclusions. As such, loaded with references to original research papers, the book serves beautifully as an introductory survey of word learning literature, and would be good for novice researchers in the field to jump-start their reading.

The book is relatively light on linguistic jargon, and should be accessible to readers without a background in linguistics, though some sections are more dense with terminology than others.

There are a number of pictures and graphs, but the book should be perfectly readable in electronic format. It is, however, presently only available in paperback.

I just finished reading Nothing to Envy, a compelling saga that weaves North Korean history together with accounts of the lives of a handful of individuals growing up in, first admiring but eventually leaving, what they came to regard as a repressive society.

North Korean culture is described as a sort of communistic monarchy: everything the citizens needed in life was to be regulated or supplied by the government, and further, everything was to be grown, built, or developed entirely within North Korea. To conduct business yourself? Illegal. To import goods from other countries? Illegal. But just so long as the government made available everything that you needed, why should you bother buying or selling independently?

The people greatly esteemed their nation’s leader Kim Il-sung and his claims to provide for all of their needs, though they had little choice. Government staff and citizen volunteers kept a close watch on the people, to ensure that they never said or did anything that opposed the official government-mandated way of life. There were even monitor guards to ensure that every home properly maintained a government-supplied portrait of Kim Il-sung, and that every citizen was wearing their Kim Il-sung lapel pin.

Televisions were rare, and physically modified by the government to pick up only North Korean broadcasts. School books rewrote history to paint the nation in a light more favorable than reality, and other nations in a light less favorable than reality. With all goods being produced strictly in-house, a wide variety of items that were commonplace elsewhere, including writing paper, pencils, books, and shoes, were scarce. Bibles were forbidden, as was Christianity: Kim Il-sung himself became a god-like figure to the people.

The government’s attempt to provide for the people worked reasonably well for several decades, until in the 1990s a growing famine reduced the government’s ability to provide food. Along with the food went most of the money, although people were still required to show up at their (now unpaid) jobs. Electricity became unreliable and inconsistently available. Sewage treatment broke down. Water became scarce. As the famine progressed, with people of all ages suffering from (and eventually dying from) severe malnutrition, North Koreans eventually came to ignore the government rules against producing their own food and conducting their own business, and slowly began to fend for themselves. The abject failure of communism led to people finding their way into their own free-market economy.

Life in North Korea improved, largely due to the homegrown free market economy and leaders grudgingly allowing foreign aid to replenish the almost non-existent food supply, but after several years of increase the government decided that things had to be brought back into order. They squelched the new free market in favor of returning to the strong socialistic lifestyle of years past, clamping down on individual business and reasserting the authority of the government to be the provider for its citizens.

The book explains this history through exemplary life stories of several people, including a teenage girl who grows up to become a schoolteacher, extolling the greatness of North Korea to her students until she doesn’t believe it herself anymore; a university student who gets his hands on American books and South Korean television broadcasts, persuading him against North Korean society; a medical doctor who grows weary of trying to save lives in a land where government regulations result in intense malnutrition affecting nearly the entire population; a mother who loses her husband and her son to the famine, and turns to illegal black market entrepreneurship selling cookies to make ends meet for herself and her daughters.

As these people lived through both the relative success of classical North Korean communism, and its absolute failure, they realized that their homeland wasn’t everything the government propaganda made it out to be. Bit by bit they came to believe that life in the surrounding nations of China and especially South Korea would be much more to their liking, and fought against social norms and government guards to relocate, often at great personal and/or financial expense.

A reader might assume that, upon fleeing North Korea, such defectors would be universally happy to be free, never to return. Many defectors, though, maintained confidence in the fundamental ideals of North Korean government, and hoped that the government would open up enough to allow them to return with impunity, to help rebuild their broken home.

Based on the popular news media, it’s easy for outsiders to depersonalize North Korea as a mysterious place totally unlike anything we may be familiar with. Reading this book provides an in-depth look at how people there actually live, showing very recognizable hopes, dreams, and desires.

Clinging to my library of pulverized trees, I read the paperback edition, but this book has very few photographs and would be plenty readable in electronic edition as well.