Letters from the October 29, 2005, issue of Science News

Food for thought

I note that pleasure activates the neurobiological response that fuels addictive behavior (“Food Fix: Neurobiology highlights similarities between obesity and drug addiction,” SN: 9/3/05, p. 155). It has long been a tenet of the 12-step programs that there is no pleasure greater than to use one’s talents to help others similarly afflicted. Perhaps we shouldn’t discount the neurological effect of that activity.

Betsy (last name withheld)

It’s a fact that drug addicts have a deficiency in certain dopamine receptors. However, without determining that such deficiency predates the addiction process, we can’t be sure that this represents a cause rather than an effect. It is equally credible that, once addicted, the drug abuser’s brain attempts to compensate for the flood of induced dopamine by reducing the number of sensitive receptors. This fits with induced drug tolerance, in which an addict becomes less sensitive to the euphoric effects of a drug over time, requiring increasing doses to achieve equal effect. Perhaps, over time, people for whom food is the euphoriant also require larger doses to achieve satisfaction.

David P. Vernon
Tucson, Ariz.

Of course, drug-based approaches (however ironic) may help addicts. But it seems like a really interesting question to ask what happens in the brains of the people who choose to change their lifestyles, whether by a 12-step program or some other method.

David Wine
Seattle, Wash.

Fishy ideas

In “Perfect Match: Tied contest gives fish no hormone rush” (SN: 9/10/05, p. 166) the mirror image isn’t really a perfect match, is it? It doesn’t itself secrete anything. Also, could the mirror be made to slowly withdraw, thus pulling the fish image away from the real fish in a simulated retreat? Let’s see then if there are any victory-induced hormones released.

W. Gregory Stewart
Los Angeles, Calif.

I may be suggesting the obvious, but it would seem useful for the researchers to try spherical mirrors with their fish to produce the illusion of either larger or smaller opponents when they see their own images.

Dan Lipp
Fort Collins, Colo.