Errors in situation awareness (SA) can degrade the decision process. One pa
rticularly troublesome SA error is the representational error, which reflec
ts problems with the misinterpretation of information based on a person's c
urrent mental model of a situation. This study investigates whether the sch
ema-relatedness of information affects the likelihood that a person will fa
ll prey to a representational error. Using a high-fidelity simulation of an
air traffic control task, two hypotheses were examined: (a) Schema-bizarre
information will affect SA more than schema-irrelevant information, and (b
) schema-unexpected information will impact SA more than the absence of sch
ema-expected information. The results supported the first hypothesis but no
t the second. These results provide an indication of the types of informati
on that affect SA. Enhancing SA by emphasizing the type of information to w
hich an operator is naturally less inclined to respond is one approach to i
mproving system design and thereby performance.