Hypothesis testing in attorney-conducted voir dire.

Attorneys may hold expectations about jurors based on stereotypes about the relationships between demographic characteristics and attitudes. Attorneys test their hypotheses about prospective jurors during voir dire, but it is unclear whether their questioning strategies are likely to produce accurate information from jurors. In 2 studies, attorneys and law students formulated voir dire questions to test a particular hypothesis about the attitudes held by a prospective juror (venireperson) and provided their subsequent inferences about that individual given certain hypothetical responses to the questions. Bayes's theorem was used to compare attorneys' actual conclusions about the venireperson with the conclusions they would reach if correctly using the available information. Attorneys' conclusions were biased by the questions they asked, and in some cases, by the hypothesis that they were asked to test. Compared with normative models derived using Bayes' theorem, attorneys overrelied on venirepersons' responses when drawing conclusions about their attitudes. These findings suggest that even if traditional attorney-conducted voir dire elicited accurate information about prospective jurors' attitudes, attorneys may not use that information to draw normatively accurate conclusions about the attitudes that they hold.

The potentially biasing effects of voir dire in juvenile waiver cases.

An analysis of transcripts from cases in which a juvenile is adjudicated in adult criminal court showed that potential jurors may be questioned about their attitudes toward juvenile waiver during voir dire. If jurors express concerns about trying juveniles in adult criminal court, they are excused from the jury for cause (Danielsen et al., Paper presented at the meetings of the American Psychology-Law Society, 2004). We conducted a series of three studies to examine whether questions about juvenile adjudication practices and juvenile offenders during voir dire influenced jurors' pretrial and post-trial judgments of defendant guilt. Jurors who viewed a juvenile qualification voir dire provided higher pretrial probabilities of defendant guilt than did jurors who watched a standard voir dire that did not contain juvenile qualification questions. However, this pretrial guilt bias as a function of voir dire type did not persist after the presentation of trial evidence. Jurors who viewed a juvenile qualification voir dire and jurors who viewed a standard voir dire did not differ in their post-trial judgments of defendant guilt. Implications for the abilities of juvenile defendants to receive a fair trial in adult court are discussed.

Instruction bias and lineup presentation moderate the effects of administrator knowledge on eyewitness identification.

Pairs (N=234) of witnesses and lineup administrators completed an identification task in which administrator knowledge, lineup presentation, instruction bias, and target presence were manipulated. Administrator knowledge had the greatest effect on identifications of the suspect for simultaneous photospreads paired with biased instructions, with single-blind administrations increasing identifications of the suspect. When biased instructions were given, single-blind administrations produced fewer foil identifications than double-blind administrations. Administrators exhibited a greater proportion of biasing behaviors during single-blind administrations than during double-blind administrations. The diagnosticity of identifications of the suspect in double-blind administrations was double their diagnosticity in single-blind administrations. These results suggest that when biasing factors are present to increase a witness's propensity to guess, single-blind administrator behavior influences witnesses to identify the suspect.