The study found that under controlled conditions, qualified FDEs were able to make correct decisions about whether one individual’s signature was either the product of a disguise or forgery process. There was also evidence of distinctive expertise among the FDEs, as the mean score of the FDEs was significantly greater than the control group. The overall rate of the FDEs errors (28.2 percent of total errors) was considerably lower than the control group (71.8 percent). Evidence from the response-time (RT) data shows that the expertise effect for FDEs stemmed from their taking into account multiple sources of visual information about signature characteristics. Whereas FDEs took into account multiple pieces of information before arriving at a decision, control subjects showed evidence of making decisions on the basis of single salient features. The longer response times of the FDEs indicate they were looking for multiple sources of information before making a decision. The eight FDEs who volunteered to participate in the study were authorized in handwriting and signature examination by NATA-accredited Australian Government laboratories. The control group consisted of 12 subjects who were La Trobe University students who volunteered to participate in the study. All participants were shown the same set of test stimuli, which were signatures extracted from a blind validation trial conducted by the university in 2004. 1 table, 3 figures, and 20 references