The effects of intranasal treatment with DDAVP on healthy, male volunteers was assessed. Subjects were asked to learn prose passages and then were given either 60 micrograms of DDAVP or saline in a double-blind procedure. Subjects were then asked to recall the passages after a 24-h delay. Treatment had no effect on recall of passages. This suggests that treatment with vasopressin affects acquisition rather than consolidation of newly learned information.