Cross-situational learning allows word learning despite exposure-by-exposure uncertainty about a words meaning, by combining information across exposures to a word. A number of experimental studies demonstrate that humans are capable of cross-situational learning. The strongest claims here are made by Yu and Smith (2007), who provide experimental data suggesting that adult humans are capable of using crosssituational learning to rapidly learn the meanings of multiple words simultaneously and despite considerable uncertainty at each exposure. We identify a flaw in their testing regime which throws their conclusions into doubt, and conduct a new experiment which remedies this methodological flaw. Our data supports a more limited view of the ability of adults to rapidly and simultaneously apply cross-situational learning in conditions of (relatively) high referential uncertainty.