Just how often do people objectify women? According to recent research, we're so used to treating women as sex objects that we can do it even when standing on our heads.In a study published in this month's issue of Psychological Science, Belgian and American psychologists took advantage of a perceptual tendency known as the inversion effect to explore the differences in what we see when we look at men and women.The idea is straightforward: we rely on somewhat different perceptual processes for recognizing people versus objects. When looking at people, we usually take in the face or body as a whole, focusing not just on the shapes of particular features but also examining the spatial relationships between them. With objects, our perceptual strategies are typically less sophisticated; we simply look for the presence or absence of individual features in deciding what we see.An interesting consequence of these perceptual processes is that flipping upside-down the target of your visual attention has different effects for human versus non-human targets. Take an object like an apple and turn it upside-down, and people still have little trouble identifying it. Invert the image of a face, however, and our visual perception becomes less reliable than usual.When these celebrity faces are inverted, it's often hard to tell that various features (eyes, mouth) have also been flipped upside-down. But when the faces themselves are right-side up, the inverted features jump off the screen; you can't help but notice them. In other words, turning a face upside-down often interrupts our normal processes of visual perception.What, you might ask, does any of this have to do with sexual objectification? Well, given that inverting images tends to interfere with visual processing of people but not objects, creative researchers decided to use the inversion effect to explore just how object-like our perceptions of women (and men) can be.Specifically, the researchers compiled a stimulus set of 48 photos of men and women wearing either swimsuits or underwear (and then, presumably, quickly cleared the search history on all of the web browsers in their lab). Half of these sexualized images were of women and half of men.These images were then presented to research participants, with half of the photos shown right-side up and half upside-down.The critical outcome measure was how well respondents were later able to recognize the people from the photographs they had seen earlier. It wasn’t the most demanding of recognition tasks—indeed, for both male and female images that had been presented right-side up, participants had an accuracy rate of 85% or higher when identifying which ones they had seen before.Respondents did a poorer job, however, recognizing male images that had previously been presented upside-down. Accuracy dropped to the low 70% range in this condition, which is what the inversion effect would predict: seeing people upside-down interferes with our normal processing of people-related images.But for the upside-down images of women, no inversion effect was found. Respondents were just as good at later identifying women they had earlier seen as upside-down as they were the women they had seen right-side up. In short, participants viewed the sexualized women much the same way they view objects. And interestingly, male and female participants demonstrated this pattern, suggesting that the objectification of women is not only a male tendency.Of course, as many a good study does, this one raises additional questions. For example, would the same pattern hold for nonsexualized images of men and women? What about for a non-college-student sample? And to what degree do a person’s own gender-related attitudes predict how he or she performs on this task?These questions aside, this research clearly illustrates the different ways we look at men and women. Sure, this is not the first study to suggest that women are often objectified. But this new experiment demonstrates that our tendency to objectify women can be observed at even the most basic of cognitive and perceptual levels: While sexualized men are often looked at as people, sexualized women are viewed (and treated) more like objects.