Over time, exposure to objectifying images can lead to self-objectification, which involves taking an observer's perspective on one's own body and chronically monitoring one's appearance. In a famous set of studies, female participants were randomly assigned to try on either a swimsuit or a sweater and complete a series of tasks. Women in the swimsuit condition felt more body shame, which in turn led them to engage in more restrained eating (i.e., leaving part of a cookie behind rather than finishing it off, suggesting that they liked the cookie but felt guilty eating all of it). They also performed worse on a math test, suggesting that their attentional resources may have been drained by the experience of trying on the swimsuit.
Presumably these women were not feeling good about their appearance during the study -- they were not expecting or choosing to wear the swimsuit, and the lighting was most likely harsh and unflattering. No one loves swimsuit shopping, even if they're doing it voluntarily. But what about those times when you are feeling good about your appearance? Objectification research is less concerned about those times, since unfortunately they are often few and far between, but they are also part of the reason why women actively choose to engage in self-objectification despite its downsides. Feeling attractive and sexy feels good, and it feels good for the same reason that feeling unattractive and unsexy feels so bad: our self-worth is wrapped up in it.
As an undergraduate at the University of Michigan, I studied self-objectification for my honors thesis research, which I conducted with Jennifer Crocker and Julie Garcia. We were interested in finding out how everyday experiences of self-objectification, in contrast to typically unpleasant lab inductions of self-objectification, might impact feelings of well-being. So we gave a group of female college students palm pilots programmed with questionnaires to carry around with them for two weeks. Surprisingly, we found that some participants seemed to benefit from their daily experiences of self-objectification. Those who were high in appearance-contingent self-worth, meaning that they based their self-worth on their appearance, and who had high self-esteem, were getting a boost because they also tended to feel more attractive in those moments when they self-objectified. But appearance-contingent participants who had low self-esteem experienced the biggest drop in well-being because they were more likely to feel unattractive in those moments.
In other words, for people who base their self-worth on appearance (aka most of us, to some extent), self-objectification may be a double-edged sword. It feels great when you're getting positive attention, but it can easily turn sour when attention is negative or lacking, and these ups and downs can wreak havoc on mental and physical health.
Even when objectification feels good, it can have negative effects, taking precious time and attention away from potentially more important tasks or goals. For example, let's say you are a female attending a professional conference. Your central goals are presumably along the lines of learning something, networking, engaging in meaningful conversations, and presenting your best work. But in the back of your mind, especially if you've seen comments like this one, by an esteemed professor of evolutionary biology, you're wondering if the men you meet are admiring your poster or something else. Even if you look like a supermodel (the missing demographic at neuroscience conferences, according to the professor mentioned above), this objectifying gaze, and your chronic awareness of it, will undoubtedly interfere with your ability to get the most out of the conference. And even in situations where your goals are more romantic, preoccupation with appearance can detract from actually getting to know someone.
There's another problem with using self-objectification as an opportunity for a self-esteem boost. Beauty, as our culture defines it, doesn't last forever. It actually starts fading pretty fast, like around age 21, if you're basing your standards on dominant cultural ideals. So unless you're able to redefine beauty in a healthier way, self-objectification can become more and more of a liability as time goes on. As Cameron Diaz gets older, she may be especially concerned with holding on to the high of positive attention that she has been used to receiving all her life, leading her, and many others, to spend huge amounts of time and money on maintaining and perfecting physical appearance. In a world where attractiveness is held in such high regard, these choices are understandable. But wouldn't it be so much easier to live in a different kind of world?
Fredrickson, B., & Roberts, T. (1997). OBJECTIFICATION THEORY. Psychology of Women Quarterly, 21 (2), 173-206 DOI: 10.1111/j.1471-6402.1997.tb00108.x