Expertise and estimating what other people know: the influence of professional experience and type of knowledge.

There is ample evidence that estimations of what other people know are often biased in the direction of one's own knowledge. Yet, it is still unclear if this bias is influenced by expertise. In Study 1, computer experts estimated the distribution of Internet concepts and general knowledge concepts among students. These estimations were compared with norm values and with estimations obtained from a sample of laypersons. Laypersons showed a stronger bias than experts. Study 2 revealed that knowledge estimations can be influenced by labeling knowledge items as specialist knowledge. The results are suggestive of ways in which communication between experts and laypersons could be enhanced. Especially in asynchronous communication situations, as for example in the use of e-mail based hot lines, if experts are to communicate effectively, they must make accurate assumptions about laypersons' knowledge of the topic.