Dreaming during scientific papers: effects of added extrinsic material.

During a series of presentations of scientific papers 40.6% of 276 subjects reported dreaming, but only 18.1% actually fell asleep. The frequency of dreaming was significantly increased by the addition of either "very boring" or "very interesting" slides to the usual ones, but not by "neutral" slides. The recall of lecture content and the proportion of audience asleep were (surprisingly) not greatly affected by the addition of extraneous slides of any sort. On the other hand, adding "very interesting" slides greatly increases audience enjoyment.