Because extraterrestrial encounters often involve the sudden appearance of one or more extraterrestrials without warning in an expected location, such as one's bedroom at night, their appearance can feel, at first, like an invasion. the extraterrestrials' use of mental telepathy, and their facility for reading one's thoughts and the contents of one's mind, can feel, to the previously traumatized person, like an old, familiar, and unwelcome intrusion into what is in our culture one's private space. Here we have the clash of two cultures, polar opposite in their assumptions. In human culture, (Western modern industrial culture, anyway) the assumption is that one's thoughts and living space are private, because individualism is prized. In extraterrestrial cultures researched thus far, it appears that living space and thoughts are inevitably shared, because of the automatic, two-way nature of the mutual telepathic ability of all members of their society. they live in a shared mind-field "commons"