Various psychological theories exist around BDSM. Some suggest that it is a form of escapism, especially when people indulge in sex-play that is submissive or infantile. The same can be said of dominant sexual activity, of course, but it is more likely that the assertive psychology involved is linked to a need to feel in control rather than to relinquish it. Some people, commonly known as switchers, can get turned on by sex-play that involves both roles although it appears to be more usual for people to prefer one or the other. Some psychological studies suggest that males tend to become interested in BDSM at a younger age than females.