If only Wolfriders have it- it's got to be a product of wolfblood mixing with elfblood. Maybe... the coneheads (and most of their pure-blooded descendants) are very communal. They live collectively, and seem to have no problem sharing their inner selves in telepathic communion. But... remember Timmain's first mind-touch with Strongbow? He couldn't take it. Maybe being mixed with a mortal creature that is native to the planet ... maybe that causes the Wolfriders to be born with a need for individuality and mental privacy. Maybe that's something the other elves just don't have?