- Jan 7, 2002
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Nalini Ambady has become famous for her research on "thin slicing," the idea that ordinary people can make accurate judgments about others amazingly quickly. We've discussed work from her lab showing that people can accurately predict teaching ability by watching just six seconds of video of a teacher at work. Other judgments, like gender, race, and age, can be made even faster. But what about less obvious traits? Nicholas Rule and Ambady designed a study to see if college students could accurately identify gay men based on photos alone. They selected 90 photos of men from dating websites, carefully choosing only headshots that didn't feature facial hair, jewelry, glasses, or other accessories. Half the photos were of men seeking male partners, and half were seeking female partners. Then the photos were shown in random order to 90 student volunteers. Photos were displayed for either 33 ms, 50 ms, 100 ms, or 6.5 or 10 seconds. In addition, some of the photos were shown with no time limit at all. Immediately after each photo was shown, a mask of scrambled face parts was shown to clear any afterimages. The students were asked to indicate whether the face they had just seen was likely to be gay or straight. Were they accurate? And if so, how quickly could they do it? Here are the results:
The students responded significantly better than chance for every time period except the 33 millisecond exposure. A chance accuracy rate would be 50 percent, and even after just a 50 millisecond exposure, the students were accurate 57 percent of the time. When the results were corrected using signal detection analysis (to compensate for the fact that fewer than 50 percent of men are gay in real life), accuracy was 62 percent at 50 milliseconds, and as high as 70 percent when self-paced.
One potential problem with this experiment is the source of the photos. Perhaps men on dating sites deliberately present themselves as heterosexual or homosexual to make themselves more attractive to potential mates. To compensate, the researchers found photos of men from Facebook. They carefully chose only photos that were taken and posted by friends or family members, not the men themselves. They used the men's profiles to learn if they were gay or straight, identifying 69 gay men and and 64 straight men. The photos were cropped to show only the faces -- even hairstyles were removed. Then the researchers repeated the original experiment using just a 50 millisecond flash, since that had been the critical interval. Fifteen student volunteers viewed the photos.
Once again, the students were significantly better than chance at identifying gay men, with an accuracy rate of 52 percent, corrected to 54 percent using signal detection analysis. While this means the students were wrong 48 percent of the time, it's nonetheless impressive, especially given the extremely short display time and the fact that hairstyles had been removed from the photos (which was not the case in the first experiment).
In both experiments, there was no different in the results for male and female respondents. Increasing the amount of time beyond 50 milliseconds offered no significant improvement in accuracy.
Why would people be so quick to judge sexual orientation? Rule and Ambady say it might have to do with efficient mate selection. Women need to be able to rule out unsuitable mates, while men need to determine who their potential competition is.
http://scienceblogs.com/cognitivedaily/2009/12/people_identify_the_sexual_ori.php
The students responded significantly better than chance for every time period except the 33 millisecond exposure. A chance accuracy rate would be 50 percent, and even after just a 50 millisecond exposure, the students were accurate 57 percent of the time. When the results were corrected using signal detection analysis (to compensate for the fact that fewer than 50 percent of men are gay in real life), accuracy was 62 percent at 50 milliseconds, and as high as 70 percent when self-paced.
One potential problem with this experiment is the source of the photos. Perhaps men on dating sites deliberately present themselves as heterosexual or homosexual to make themselves more attractive to potential mates. To compensate, the researchers found photos of men from Facebook. They carefully chose only photos that were taken and posted by friends or family members, not the men themselves. They used the men's profiles to learn if they were gay or straight, identifying 69 gay men and and 64 straight men. The photos were cropped to show only the faces -- even hairstyles were removed. Then the researchers repeated the original experiment using just a 50 millisecond flash, since that had been the critical interval. Fifteen student volunteers viewed the photos.
Once again, the students were significantly better than chance at identifying gay men, with an accuracy rate of 52 percent, corrected to 54 percent using signal detection analysis. While this means the students were wrong 48 percent of the time, it's nonetheless impressive, especially given the extremely short display time and the fact that hairstyles had been removed from the photos (which was not the case in the first experiment).
In both experiments, there was no different in the results for male and female respondents. Increasing the amount of time beyond 50 milliseconds offered no significant improvement in accuracy.
Why would people be so quick to judge sexual orientation? Rule and Ambady say it might have to do with efficient mate selection. Women need to be able to rule out unsuitable mates, while men need to determine who their potential competition is.
http://scienceblogs.com/cognitivedaily/2009/12/people_identify_the_sexual_ori.php
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