Current research on law and psychology, particularly in the area of behavioral decision theory, assumes that all people have a similar psychological make-up. It assumes that all defendants, jurors, judges and lawmakers are subject to the same predictive errors of thought, known as cognitive biases, and apply the same heuristics, or rules of thumb. To date, the effect of individual and group differences upon these cognitive processes has neither been discussed nor evaluated. This paper analyzes how psychological processes and biases vary across cultures, and reveals the way these differences result in uneven treatment and incentives in American tort law’s actual causation and foreseeability inquiries.