This article originally appeared on VICE US.

Let's get two things out of the way: First of all, there are a lot of reasons to get a boob job, none of which are anyone else's business. Second, the perfect boob does not exist.

But if you were a plastic surgeon hoping to be the Michelangelo of one person's idealized breasts, it would help to have a shared language of what's aesthetically important. Most plastic surgeons accomplish this over the course of several consultations, talking to the patient about what will make them happy.

In an attempt to improve this process, a team of researchers in Poland used eye-tracking technology to see what parts of the boob people looked at when assessing the symmetry and relative attractiveness of breasts. What they found was that what people notice most are the nipples and the underboob.

The study analyzed the gazes of 50 men and 50 women, using eye-tracking technology as they looked at images of breasts. The study makes no mention of sexual preferences or gender identities of the participants beyond "Caucasian" and "male or female," but does note that they're all from a similar cultural background. The study is published in the December issue of Plastic and Reconstructive Surgery.

"Terms such as 'beauty' or 'aesthetics' are subjective and thus poorly defined and understood," the study's lead author, Piotr Pietruski, told Motherboard. "Due to this fact, both aesthetic and reconstructive breast surgery suffer from the lack of a standardized method of postoperative results analysis... Eye-tracking technology enables quantitative analysis of observer's visual perception of specific stimuli, such as comprehension of breast aesthetics and symmetry."

The researchers presented participants with images of all sorts of computer-generated boobs—Saggy ones, perky ones, at various cup sizes—and asked them to evaluate them from 1, or "poor," to 10, or "excellent." The images in the study are all of white skin tones, with a similar, slim build.

Pietruski et al. Areas of interest for each breast projection.

If the subject's gaze lingered on any part for longer than 100 milliseconds, the researchers counted it as intentional. They placed the points where people most often looked onto a map of the breasts, and revealed that people most often looked at the nipple-areola area—which shouldn't be surprising, as our eyes are drawn toward areas of contrast.

In the paper, the researchers acknowledge that following people's eyes doesn't actually tell them much about what people find attractive—just what people focus on. It's often difficult for surgeons and patients to agree on what makes a good boob job, the paper says, because patients come from a variety of cultural backgrounds that influence their preference. More studies on larger scales, with more diverse participants are needed, the researchers say. But they foresee uses for a "universal scale" for evaluating breast aesthetics, to help patients and surgeons better communicate. Pietruski said that in the future, an AI could use something like the findings of their work, and the map they were able to draw of the breast, to automatically evaluate boobs.

"Personally, I believe that the most important potential application of eye-tracking technology could be the development of an artificial intelligence-based algorithm for the analysis of various body regions' attractiveness," Pietruski told Motherboard.

Again, there are many reasons why someone wants or needs to get a boob job, and any tool that could make that person more satisfied with the result of a plastic or reconstructive surgery is obviously good. A universally recognized "attractive" boob can't be determined if we just track enough eyeballs. Even if we surveyed every human on the planet and created the average boob based on that data, that boob won't necessarily satisfy every patient.