Maybe the standards are different. I wonder how many of the tank people had used hallucinogens, and were only reporting really noticeable hallucinations?

> Among the nine participants who scored high on the first survey, five reported having hallucinations of faces during the sensory deprivation, and six reported seeing other objects or shapes that weren’t there. Four also noted an unusually heightened sense of smell, and two sensed an “evil presence” in the room. Almost all reported that they had “experienced something very special or important” during the experiment.

(A heightened sense of smell, really?)