title: The impact of prior knowledge from participant instructions in a mock crime P300 Concealed Information Test.
abstract: In P300-Concealed Information Tests used with mock crime scenarios, the amount of detail revealed to a participant prior to the commission of the mock crime can have a serious impact on a study's validity. We predicted that exposure to crime details through instructions would bias detection rates toward enhanced sensitivity. In a 2 × 2 factorial design, participants were either informed (through mock crime instructions) or naïve as to the identity of a to-be-stolen item, and then either committed (guilty) or did not commit (innocent) the crime. Results showed that prior knowledge of the stolen item was sufficient to cause 69% of innocent-informed participants to be incorrectly classified as guilty. Further, we found a trend toward enhanced detection rate for guilty-informed participants over guilty-naïve participants. Results suggest that revealing details to participants through instructions biases detection rates in the P300-CIT toward enhanced sensitivity.
authors.affiliation: Northwestern University, United States. Electronic address: m-winograd@u.northwestern.edu.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Winograd
authors.affiliation: Northwestern University, United States.
authors.forename: J Peter
authors.initials: JP
authors.lastname: Rosenfeld
mesh_terms: D000293:Adolescent; D003415:Crime / Q000523:psychology*; D008192:Deception; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology*; D006167:Guilt; D006801:Humans; D008014:Lie Detection / Q000523:psychology*; D008297:Male; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult
keywords: Complex Trial Protocol; Concealed Information Test; ERP; Ecological validity; Mock crime; P300