I just found this article discussing whether or not experiences of “mystical fireworks” are something that any human being can experience at any time, or if they are dependent on the support and faciliation of a guru.  While the author’s experiments into the matter are less than rigorously scientific, he was able to consistently demonstrate that the majority of his high-school students, when given brief meditation instruction combined with the suggestion of possibly seeing lights or hearing sounds did, in fact, see lights or hear sounds.  The author’s conclusion is that gurus take undue credit for experiences that he believes are already hard-wired into human neurology.

The Kirpal Statistics