Charged Up and Anchored Down: A Test of Two Pathways to Judgmental and Decisional Anchoring Biases in Plea Negotiations

Some prosecutors strategically overcharge defendants, implementing extreme potential trial sentences (“PTS”) as a means of coercing defendants to plead guilty instead of going to trial. This study analyzes how PTS impacts the cognitive processes of defendants and defense attorneys that influence judgment and decision-making in the plea context. Specifically, the researchers examine whether the “anchor” point—the point at which any readily-available salient value can unduly bias judgments when people make decisions about unfamiliar topics—influences the plea decision. Three separate experiments revealed that defendants and defense attorneys are influenced by anchoring bias. First, high PTS increased willingness to accept pleas with longer sentences. Second, varying magnitudes of PTS did not bias judgments of related case characteristics (e.g., crime severity, strength of evidence, or probability of conviction). Third, instructions to consider mitigating (i.e., anchor-inconsistent) evidence led to a decrease in anchoring bias. The study ultimately reveals that both defendants and defense attorneys are vulnerable to cognitive errors that result in accepting plea deals in the face of strategically-overcharged PTS.

“Legal decision-makers were willing to accept jail sentences that were significantly longer when exposed to a high compared to moderate [potential trial sentence] anchor.” p. 449