Subliminal

exercise, the students were told, was to prepare for a test with the assistance of a computerized tutoring session. The topics taught ranged from “mass media” to “love and relationships.” After completing the tutoring and the test, the students received an evaluation of their performance, delivered either by the same computer that taught them or by another computer. Finally, the students themselves completed the equivalent of a course evaluation form, in which they rated both the course and their computer tutor.

Nass was not really interested in conducting a computer course on mass media or love and relationships. These earnest students were Nass’s cowbirds, and in a series of experiments he and some colleagues studied them carefully, gathering data on the way they responded to the lifeless electronic computer, gauging whether they would react to a machine’s voice as if the machine had human feelings, motivations, or even a human gender. It would be absurd, of course, to expect the students to say “Excuse me” if they bumped into the monitor. That would be a conscious reaction, and in their conscious ruminations, these students certainly realized that the machine was not a person. But Nass was interested in another level of their behavior, behavior the students did not purposely engage in, social behavior he describes as “automatic and unconscious.”

In one of the experiments, the researchers arranged for half their subjects to be tutored and evaluated by computers with male voices, and half by computers with female voices. Other than that, there was no difference in the sessions—the male computers presented the same information in the same sequence as the females, and the male and female computers delivered identical assessments of the students’ performance. As we’ll see in Chapter 7, if the tutors had been real people, the students’ evaluations of their teachers would probably reflect certain gender stereotypes. For example, consider the stereotype that women know more about relationship issues than men. Ask a woman what bonds couples together, and you might expect her to respond, “Open communication and shared intimacy.” Ask a guy, and you might expect him to say, “Huh?” Studies show that as a result of this stereotype, even when a woman and a man have equal ability in that area, the woman is often perceived as more competent. Nash sought to discover whether the students would apply those same gender stereotypes to the computers.

They did. Those who had female-voiced tutors for the love-and-relationships material rated their teachers as having more sophisticated knowledge of the subject than did those who had male-voiced tutors, even though the two computers had given identical lessons. But the “male” and “female” computers got equal ratings when the topic was a gender-neutral one, like mass media. Another unfortunate gender stereotype suggests that forcefulness is desirable in men, but unseemly in women. And sure enough, students who heard a forceful male-voiced computer tutor rated it as being significantly more likable than those who heard a forceful female-voiced tutor, even though, again, both the male and the female voices had uttered the same words. Apparently, even when coming from a computer, an assertive personality in a female is more likely to come off as overbearing or bossy than the same personality in a male.

The researchers also investigated whether people will apply the social norms of politeness to computers. For example, when put in a position where they have to criticize someone face-to-face, people often hesitate or sugarcoat their true opinion. Suppose I ask my students, “Did you like my discussion of the stochastic nature of the foraging habits of wildebeests?” Judging from my experience, I’ll get a bunch of nods and a few audible murmurs. But no one will be honest enough to say, “Wildebeests? I didn’t hear a word of your boring lecture. But the monotonic drone of your voice did provide a soothing background as I surfed the web on my laptop.” Not even those who sat in the front row and clearly were surfing the web on their laptops would be that blunt. Instead, students save that kind of critique for their anonymous course-evaluation forms. But what if the one asking for the input was a talking computer? Would the students have the same inhibition against delivering a harsh judgment “face-to-face” to a machine? Nass and his colleagues asked half the students to enter their course evaluation on the same computer that had tutored them, and the other half to enter it on a different machine, a machine that had a different voice. Certainly the students would not consciously sugarcoat their words to avoid hurting the machine’s feelings—but as you probably guessed, they did indeed hesitate to criticize the computer to its “face.” That is, they rated the computer teacher as far more likable and competent when offering their judgment directly to that computer than when a different computer was gathering the input.⁴

Having social relations with a prerecorded voice is not a trait you’d want to mention in a job application. But, like the cowbirds, these students did treat it as if it were a member of their species, even though there was no actual person attached. Hard to believe? It was for the actual subjects. When, after some of the studies had been concluded, the researchers informed the students of the experiment’s true purpose, they all insisted with great confidence that they would never apply social norms to a computer.⁵ The research shows they were wrong. While our conscious minds are busy thinking about the meaning of the words people utter, our unconscious is busy judging the speaker by other criteria, and the human voice connects with a receiver deep within the human brain, whether that voice emanates from a human being or not.

PEOPLE SPEND A lot of time talking and thinking about how members of the opposite sex look but very little time paying attention to how they sound. To our unconscious minds, however, voice is very important. Our genus, Homo, has been evolving for a couple million years. Brain evolution happens over many thousands or millions of years, but we’ve lived in civilized society for less than 1 percent of that time. That means that though we may pack our heads full of twenty-first-century knowledge, the organ inside our skull is still a Stone Age brain. We think of ourselves as a civilized species, but our brains are designed to meet the challenges of an earlier era. Among birds and many other animals, voice seems to play a great role in meeting one of those demands—reproduction—and it seems to be similarly important in humans. As we’ll see, we pick up a great many sophisticated signals from the tone and quality of a person’s voice and from the cadence, but perhaps the most important way we relate to voice is directly analogous to the reaction of the cowbirds, for in humans, too, females are attracted to males by certain aspects of their “call.”

Women may disagree on whether they prefer dark-skinned men with beards, clean-shaven blonds, or men of any appearance sitting in the driver’s seat of a Ferrari—but when asked to rate men they can hear but not see, women miraculously tend to agree: men with deeper voices are rated as more attractive.⁶ Asked to guess the physical characteristics of the men whose voices they hear in such experiments, women tend to associate low voices with men who are tall, muscular, and hairy-chested—traits commonly considered sexy.

As for men, a group of scientists recently discovered that men unconsciously adjust the pitch of their voices higher or lower in accordance with their assessment of where they stand on the dominance hierarchy with respect to possible competitors. In that experiment, which involved a couple hundred men in their twenties, each man was told he’d be competing with another man for a lunch date with an attractive woman in a nearby room.⁷ The competitor, it was explained, was a man in a third room.

Each contestant communicated with the woman via a digital video feed, but when he communicated with the other man, he could only hear him, and not see him. In reality, both the competitor and the woman were confederates of the researchers, and they followed a fixed script. Each man was asked to discuss—with both the woman and his competitor—the reasons he might be respected or admired by other men. Then, after pouring his heart out about his prowess on the basketball court, his potential for winning the Nobel Prize, or his recipe for asparagus quiche, the session was ended, and he was asked to answer some questions assessing himself, his competitor, and the woman. The subjects were then dismissed. There would, alas, be no winners anointed.

The researchers analyzed a tape recording of the male contestants’ voices and scrutinized each man’s answers to the questionnaire. One issue the questionnaires probed was the contestant’s appraisal of his level of physical dominance as compared to that of his competitor. And the researchers found that when the participants believed they were physically dominant—that is, more powerful and aggressive—they lowered the pitch of their voices, and when they believed they were less dominant, they raised the pitch, all apparently without realizing what they were doing.

From the point of view of evolution, what’s interesting about all this is that a woman’s attraction to men with low voices is most pronounced when she is in the fertile phase of her ovulatory cycle.⁸ What’s more, not only do women’s voice preferences vary with the phases of their reproductive cycle, so do their own voices—in their pitch and smoothness—and research indicates that the greater a woman’s risk of conception, the sexier men find her voice.⁹ As a result, both women and men are especially attracted to each other’s voices during a woman’s fertile period. The obvious conclusion is that our voices act as subliminal advertisements for our sexuality. During a woman’s fertile phase, those ads flash brightly on both