In Brief

Contrary to popular belief, character witnesses' court testimony may actually hurt the defendants they are trying to help: Cross-examining prosecutors can make jurors question witnesses' credibility and thus see defendants more negatively than if they never heard supporting testimony at all, says a recent study in APA's Journal of Applied Psychology (Vol. 89, No. 2).

The reasons? People tend to emphasize negative information about others over positive and prefer tangible examples of a defendant's behavior over vague generalities, posit study authors Jennifer S. Hunt, PhD, of the University of Nebraska-Lincoln and Thomas Lee Budesheim, PhD, of Creighton University. Beyond that, jurors wrongly incorporate negative character attacks by cross-examining prosecutors--meant only to erode witness credibility--into their judgments of the defendant, the authors say.

The two psychologists gave 188 undergraduate psychology students transcripts of a mock burglary trial and randomly divided them into six groups. A control group read a transcript with no character witness. Two groups read transcripts with character evidence supporting the defendant. One transcript featured generalized evidence ("Martin is an honest guy"); the other featured anecdotal evidence ("We had a shipment problem at work, and Martin confessed it was his fault.").

Two other groups read one of these two transcripts along with negative, example-laden cross-examination that impeached the witness's credibility ("Did you know Martin lied on his job application?"). The final group read a transcript that included a rebuttal witness's testimony. Then, the participants rated the defendant's character traits and whether they would convict him.

By rule, jurors can't judge a defendant using the negative information prosecutors raise when cross-examining character witnesses; it's meant only to impeach a witness's credibility. Even so, Hunt and Budesheim found that a prosecutor's detailed, negative impeachment of the character witness outweighed that witness's positive character evidence--even specific, positive evidence--when participants formed conviction judgments.

The findings challenge the usefulness of character witnesses, considering that, by rule, such witnesses can only be introduced by the defense and can only give generalized testimony. When they do, the prosecution can use specific evidence to counterattack the character witness. By using general character evidence to bolster its case, the defense may actually hand the prosecution an opportunity to introduce concrete, negative evidence against the defendant, ultimately leading to a conviction, according to the study's researchers.

"Defense attorneys offer very weak evidence, and the prosecution is allowed to bring out the big guns to refute it," Hunt explains.

Hunt says attorneys should know character evidence's pitfalls and, in most cases, avoid it altogether: "It really did make us reflect on the irony of defendants trying to help themselves, but ending up hurting themselves because of how jurors process information."