Letters

You do us a disservice when you buy into the stereotype that clergy are narrowly focused and out of touch'

By Fenella Saunders|Wednesday, September 01, 1999


Echoes of the Last Big Bang Man

I feel that it is high time Ralph Alpher's work was acknowledged ["The Last Big Bang Man Left Standing," July]. Alpher has not been completely ignored, however: George Gamow makes several references to his work in The Creation of the Universe, published in 1952. I also remember reading in one of Gamow's books a reference to the universe being created in a great explosion, which he called a "big bang." I believe that was the first use of this expression in this context.
Yalcin Peker
ATLANTA, GA.


People of God . . . and the Lab

In your July "Letter from Discover," you reveal an antireligious prejudice: Reverend Backus "may be the only minister in the United States who can appreciate the articles found in the Proceedings of the IEEE." I think you'd be surprised at the diversity of people entering the ministry these days. One of my classmates at seminary held a Ph.D. in biology, and I've known clergy who, prior to seminary, earned degrees such as M.D., J.D., and Ed.D. You do us a disservice when you buy into the stereotype that clergy are narrowly focused and out of touch.
Rev. Steven R.P. Weston, B.S., M.Div.
FOSSTON, MINN.


Sticking Points

Wouldn't an experiment in a vacuum help prove or disprove the suction-cup theory of pressure-sensitive tape ["The Physics of . . . Tape," July]? And it would seem that, under the theory, moisture, which helps a suction cup stick, should help tape stick. But as we know, it doesn't.
Jim Horton
NAPERVILLE, ILL.


Physicist Costantino Creton replies: Pressure-sensitive adhesives do work in a vacuum. The microscopic suction cups described by the adhesive model do not work in the same manner as household suction cups, which are made of rubber and require a pressure differential between the outside and the inside to stay airtight and therefore stick to the wall. Most of the work to get them unstuck is done against that pressure differential. Adhesives are much softer, closer to a liquid in many ways, and make molecular contact with a surface even in the absence of a pressure differential. Therefore the "bubbles" stay trapped at the interface even in a vacuum. When a tensile force is applied, the suction-cup effect contributes only a very small part to the energy of debonding, most of which is the product of elastic deformation and viscous flow of the adhesive.

If a suction cup is wet, the water helps to make it airtight and therefore stick. In an adhesive, water helps the microscopic cups merge with one another and reduces the effectiveness of the adhesive.


The Wanderers

The differences in male and female brain size found by Dean Falk may well be associated with the visuo-spatial skills required for emigration from a social group, but the association between this and philandering is tenuous [R&D;, July].

While male rhesus monkeys do leave their natal group at maturity, they do so to join another group, not roam from female to female. So-called bachelor groups of monkeys (males that have left their natal group but not yet managed to join another) have virtually no access to females. And female rhesus monkeys, which stay in their natal group, may copulate with several males.

Gibbons (both males and females emigrate at maturity) are monogamous only in their social, as opposed to mating, system. Extra-pair matings are common, especially among males.
Megan D. Matheson, Ph.D.
TIFTON, GA.

Dean Falk and John Redmond reply: It is entirely possible that larger brains in male rhesus monkeys may not be directly related to philandering but to a greater navigating ability in polygynous males. We hypothesize that the visuo-spatial skills of rhesus monkeys and humans were differentially selected in male and female representatives of a polygynous common ancestor in conjunction with male navigation, which may have been related to reproductive success. To explore this hypothesis, researchers in our laboratory are investigating brain-body sizes in male and female primates in a number of species that differ in their mating systems and residence patterns.


The Discover Awards

I realize that science, especially physics and engineering, is still dominated by men, but are there no innovations in which a woman had a hand? I hope in the future that these awards are better able to reflect women and minorities.
Vanessa Fell Haluska
DAYTON, N.J.

This past year, in an effort to increase applications from women and minorities, we sent notification of the Awards program to several professional associations that serve these groups. Although we do not consider race or sex in evaluating applicants, we will continue to spread our net wide in hopes that our finalists will one day better reflect the growing diversity of the field.


On the Face of It

As a professional actress and an amateur science buff, I was horrified by Marian Stewart Bartlett's attempt to equate human emotional response--as defined by involuntary facial gestures--with whether or not someone is telling the truth [R&D;, July].

Microexpression analysis will fail even more miserably than polygraph testing for a variety of reasons. First, a baseline photograph of the subject's face "devoid of all expression" cannot be taken. The so-called "involuntary facial gestures" that the software uses to track, map out, and define human emotion (as if that were even possible) are a direct result of the subjects' internal emotional life.

The second difficulty in Bartlett's proposed application of this software is the idea that emotional expression can be quantified. It brings to mind that famous case in Australia, in which a mother was wrongfully imprisoned for killing her child. No one believed that a dingo had eaten her baby, because her involuntary emotional reaction to losing her child wasn't the "correct" one.

Practicing a fake smile with wrinkles around my eyes,
M. Kennedy
LOS ANGELES, CALIF.

Cognitive scientist Marian Stewart Bartlett replies: The system we are developing does not directly detect lies. Rather, it detects which facial muscles have moved. The primary purpose of this system is to provide a tool for basic scientific research into facial behavior. This research addresses questions such as: Do people in different cultures move the same muscles during sadness? (The answer is yes.) There is more than 20 years of research establishing relationships between facial muscle movement and emotional state, emotional intensity, and other factors such as motivation and truthfulness. The interpretation of the facial movement data provided by our system rests on this body of research.

Detection of deceit is a possible application of this system. Facial muscle measurement can provide information about whether an expression of emotion is posed or genuine, as well as information about emotion that the individual may be attempting to hide. Facial measurement does not directly indicate whether a person's words are truthful. Deciding whether or not a posed expression or a leaked emotion is consistent with truth is a judgment that must be made very carefully. Our system does not make this judgment.

This brings us to another important issue: equating human emotional response with truthfulness. Many people are surprised to learn that "lie detectors" such as the polygraph test are based on that same premise. The polygraph test does not directly measure lying, but instead measures nonspecific emotional arousal. It is important to obtain as much information as possible before making a polygraph-based judgment as to whether someone is lying.


To Air Is Human

In her sidebar to "The Great White's Ways" [June], Wendy Marston refers to the "oxygen tank" in the mouth of the Jaws shark. Divers do not use oxygen--we use air! The only time we use straight O2 is for staged decompression at very shallow depths, usually 20 feet of seawater or less, to allow the body to rid itself of nitrogen at a much greater rate via the increased osmotic pressure gradient.

Divers use more than 21 percent oxygen only in special applications, such as mixed-gas diving or, recently, via Nitrox, an enriched form of air composed of 22 to 40 percent oxygen and is used at depths between 40 and 130 feet of seawater.
Greg McTigue
Dive Team Leader
CLINTON FIRST AID & RESQUE SQUAD
WATER RESQUE TEAM
CLINTON, N.J.


Erratum

In the August Vital Signs, we referred to the antihistamine Seldane as an antibiotic. The error was not the author's and was inserted in editing.
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