I am trying to comprehend the existence of mirror neurons in “A Revealing Reflection,” by David Dobbs. More specifically, how can one differentiate between a normal neuron and a mirror neuron? What would the ratio be between the two? Would the ability to recall and replay memories be greater in those who have more mirror neurons versus those who have fewer?

John Spaine
via e-mail

DOBBS REPLIES: Mirror neurons are all premotor neurons—that is, specialized neurons in the cortex that fire to activate motor neurons, which in turn send signals to muscles to contract, relax or whatnot. Although the term “mirror neurons” seems to have taken, I think it more helpful to speak of “neuron mirroring,” because what has been discovered is not a new type of neuron but a new activity and function in premotor neurons, which have already been heavily studied.

As premotor neurons, mirror neurons account for only a tiny percentage of all neurons in the brain. No one knows yet whether all premotor neurons serve a mirroring function. And no one knows whether some people have a lot more mirror neurons (or neuron mirroring) than others. Some studies, however, suggest that a lack of neuron mirroring produces problems in learning, empathy and perhaps memory. The article, for instance, mentioned that preliminary research suggests that autistic children show less neuron-mirroring activity in brain scans than nonautistic children do. Such a deficit might be either cause or effect of autism, but the link seems significant, and it stands to reason that if mirror neurons play as big a role in learning, social understanding and empathy as the leading researchers think they do, a lack of them would put you at a disadvantage.

You can find musings by leading researchers on these issues at an online forum on mirror neurons at the European Science Foundation Web site. Go to www.interdisciplines.org/mirror


As Yvonne Raley notes in her article “Electric Thoughts?” computers and human brains both process information. Yet the mechanics, speed and reason for doing so are wildly divergent. Ask the average human to add 50 pairs of six-digit numbers; it will take at least 30 minutes, and there is bound to be at least one error. My computer can do that in microseconds, flawlessly.

But a computer cannot compose a letter, enjoy listening to Beethoven, scratch an itch on my back, watch three grandchildren at play, or listen in case the soup boils over on the stove. No computer in the world has enough capacity to store my memories, going back well over 65 years. Still, I don’t have to repeat a name several times to my computer at 10-minute intervals to store it.

The computer is a tool; so is a hammer. They may not appear to have much in common, but they share identical IQs. Making a robot in humanoid shape that can learn, communicate and function in humanoid forms is a worthwhile project. Yet thinking is far more complex. It involves not just logic but also emotions, feelings, desires and, most of all, the remembered experiences of a lifetime. Perhaps someday someone will build a machine that can think, but it will not be a computer. And why bother? It is so much more fun making thinkers the old-fashioned way.

Peter Charters
Kinmount, Ontario


Andreas Heinz's article on the mental effects of alcoholism, “Staying Sober,” helps us understand the physical basis for why alcoholics have a difficult time overcoming their addiction and why they may find it easier than others to imbibe in the first place. Statements by the author, however, such as “drugs that can reverse the brain's alcohol-altered chemistry may be necessary” and “victims can no longer free themselves from the bottle” help to perpetuate the false stigma that an alcoholic is completely powerless over his or her addiction—a viewpoint that is thoroughly rebutted by the research on the subject, and a belief that when internalized contributes to relapse.

Research has confirmed time and again the ability of people who have such altered brain chemistry to resist addictive behavior, nonetheless. With enough positive incentives, even the most severe alcoholics can resist a first drink despite severe withdrawal symptoms and will resist a second drink after having had a first. We know that many have overcome their cycle of addictions on their own and without drugs.

We should be compassionate in realizing that the alcoholic struggles with his or her addiction and may be unable to see how to overcome it successfully. But it is going too far to suggest that just because we can now explain to some extent the withdrawal, obsessiveness and pleasure alcoholics experience in terms of brain chemistry, self-efficacy and other life-affirming values are insufficient for avoiding and overcoming addiction.

Given our current state of knowledge, it would be more prudent to consider drugs as a potentially helpful tool, as opposed to being “necessary,” as well as to research the mental impact of the aforementioned values that have already proved successful. It may in fact be that such values themselves have a powerful effect on the brain's chemistry, serving both to protect one from slipping into addiction and to reverse the reinforcing chemistry that results from long-term overconsumption.

Ted Melaniul
St. Charles, Mo.


In “Bird Brains? Hardly,” Christine Scholtyssek speculates on Alex the parrot's thought process in coining the term “banerry” for apple. Her hypothesis on the association of cherry with apple based on shape and color seems probable. Her hypothesis, however, on banana with cherry based on taste may be oversimplifying Alex's thought process. He may have been thinking more abstractly. A banana has a white pithy core with a different colored skin. So does an apple.

Jim Buonocore
via e-mail


I took the Head Games test. I qualified for Mensa many years ago, and I always like to see if I still have enough smarts to chew gum and walk at the same time (I am 70). I missed three questions, two of which I could not answer and one where I got a different answer.

In question number five, “tapes” does not mean “adheres,” at least in any dictionary I have. I came up with a different answer for question seven: all the words contain two vowels except “hurt.” Perhaps mine is an easier answer?

I enjoy the test, but perhaps the puzzler, Abbie Salny, has a better dictionary than I do.

Kurt Bramer
via e-mail