COMMITMENTS : THE STRANGEST SPECIES : Mind and Body Don’t Always See Eye to Eye

Do the brain and the body agree on what’s sexy?

It seems true for men. But in some cases, women experience mixed signals: Though their minds may be turned off by a crude, boring sex film, their bodies may become mildly aroused anyway.

Sex researcher Ellen Laan showed 11-minute excerpts of two films--one produced by a man, the other by a woman--to 47 women, ages 18-38. She and three co-researchers monitored two indicators of sexual arousal: pulse rate and blood flow to the genitals.

Laan, of the University of Amsterdam, hypothesized that the more romantic “erotica” filmed from a woman’s point of view would cause greater mind / body arousal than the man’s more graphic film.

Sure enough, the women’s psychological response to the male-produced film was mostly indifference. They described it as “coarse,” “awful” and “obscene,” while the woman’s film rated adjectives such as “beautiful,” “sensual” and “cute.”

Yet both films produced roughly the same measure of automatic physical arousal.

“This finding suggests that sexual response is involuntary, like blushing,” said Laan, who has researched female sexuality for five years. Most of the subjects were not even aware their bodies were registering arousal.

The woman’s film elicited higher levels of psychological enjoyment than the man’s, Laan said. But even women who rated the man-made film “distasteful” were stimulated involuntarily, showing low to moderate physical arousal.

Laan infers that human genitals sometimes operate independently and are designed to become aroused by certain stimuli, regardless of what the brain thinks. Ultimately, though, the brain has veto power.

“Erotic stimuli are built into us and designed to override many other stimuli like [the physiological drives] of hunger and exhaustion,” said Julia Heiman, a professor of psychiatry at the University of Washington at Seattle. She has conducted numerous studies on sexually dysfunctional women since the 1970s, finding that explicit films are more arousing than erotic literature and audiotapes, romantic literature or sexual fantasies.

Heiman says a woman’s interpretation of erotic material determines whether it makes her want to have sex. She suggested that 11-minute excerpts may not allow enough time for the mind and body to reach agreement on sexual arousal.

“The issue is what women attach to erotic material, positive or negative feelings,” she said. “If a woman continues to have negative feelings about a film, one could expect it’ll dampen levels of arousal.”

Another explanation is offered by psychologist Donald Symons, author of “The Evolution of Human Sexuality” (Oxford University Press, 1978). He writes that women’s mind / body independence is a protective adaptation to an environment where men wield physical power.

If a woman was forced to have sex when she had no desire to do so--a scenario even more common in ancestral societies than it is today--the body automatically prepared so that injuries were prevented.

“Pleasure is one side of the sexual coin,” said Laan. “But for women, danger is the other side.”