“…From observation posts, visitors watch the behaviour of the canaries,
mice and houseflies for signs of intoxication and form their own
conclusions. “The experiment is completed in the minds of the visitors,”
says Höller. “It’s very unscientific.” In other words, it’s an open
question whether the reindeer are even fed the mushrooms at all: the
power of suggestion makes you likely to observe something that may not
take place.” – from the guardian