Contact’s prejudice-reducing effects accumulate only after repeated interventions

Evidence

Indeed, the major findings of the Robbers’ Cave study would not have emerged without its longitudinal design (Pettigrew 1991a). The initial intergroup contact situations had little effect. Only after repeated treatments did the positive results cumulate. — Thomas F. Pettigrew, Intergroup Contact Theory, 29

Categorization

• XREF: Cuts against single-shot diversity-training or one-off contact interventions, echoing dosage-response findings in behavior change.
• SEED: Angle: ‘One Friendly Lunch Won’t Fix Prejudice’ — why dosage and repetition, not mere exposure, drive attitude change.