These are fan-made modifications of World of Warcraft avatars specifically made to appear attractive
The study showed that once a woman playing the game World of Warcraft was identified as female and her avatar was also female with a "low" level of attractiveness defined by those conducting the study, she won't get as much assistance from other players.
On the other hand, female players should expect as much assistance as any of the male players if their avatar has a high level of attractiveness (also definined by the researchers). In other words, the way some players behave in video games mirrors the way they think in real life.
The study goes a little further to say that players gave less assistance if a female player used a male avatar, but players would offer the same amount of help if a male player used a female avatar with any level of attractiveness. That's the reverse of what is generally approved by today's society, where a woman taking on a cross-gender role is more widely accepted than a man adopting a female role, which the study also notes.
So, you could say that female players have it even worse in the virtual world than they do in real life.
In the real world, discrimination of all sorts, including gender and racial, is at least recognized and some action is being taken against it. But when online, discriminators can hide behind veil of anonymity, which means they have less accountability for their actions than in their offline lives.
World of Warcraft/Blizzard Entertainment The avatars used in the study. The avatars rated with "high attractiveness" look much more human than those rated with "medium" or "low" attractiveness.
Of course, offending players aren't entirely anonymous. Victims of racial or gender abuse in video games can easily report aggressors, and gaming services, like Xbox Live and the PlayStation Network, can dish out some form of punishment, like banning.
But that kind of deterrent is mainly designed for obvious offenses. What's not so obvious is discrimination like the Penn State study reveals, which the video game industry will have a hard time regulating due to the subtle nature of this kind of prejudice.