J. Cooper et Im. Neuhaus, The "hired gun" effect: Assessing the effect of pay, frequency of testifying, and credentials on the perception of expert testimony, LAW HUMAN B, 24(2), 2000, pp. 149-171
Three experiments addressed the proposition that jurors use short cuts in p
rocessing information when confronted with expert scientific testimony. The
results of the first two studies demonstrated that experts who are highly
paid for their testimony and who testify frequently are perceived as "hired
guns." They ave neither liked nor believed. The results of the third exper
iment replicated the hired gun effect and showed that it is most likely to
occur when the testimony is complex and cannot be easily processed. The res
ults were discussed in terms of the theoretical differences between central
and peripheral processing of persuasive messages in a legal context.