measures, statistical standards for accepting a conclusion, and replications offindings over time.
The ultimate “truth” of a particular explanation of human behavior may be unknowable but, over time and multiple investigations, theoriesare revised and psychologists are able to construct increasingly useful explanationsof human behavior. Judgments made by scientists are not dichotomous (likeguilty or not guilty); they are probabilistic. That is, scientific conclusions arestated in terms of probabilities. Indeed, the tendency for scientists to talk in termsof likelihoods and to couch their conclusions in caveats and qualifiers is somethingthe courts (and the general public) find frustrating. In science, no conclusionis final and current understandings are tentative and subject to revision.Another implication of the differing goals of psychological science and thelegal system is that psychology emphasizes the characteristics of groups, whilethe law emphasizes individual cases (Goldberg, 1994).
Psychological scientistsconduct research to uncover general principles of human behavior. Because individualsare idiosyncratic, knowing how one person behaves does not necessarilytell us how everyone else behaves in the same situation. The reverse is alsotrue—knowing how people behave in general does not necessarily tell us whya specific defendant behaved in a particular way.
This often creates problems. Ifa 10-year-old boy walks into his fourth-grade classroom with a loaded gun andshoots one of his classmates, a psychologist might be called to testify. A developmentalpsychologist might testify about the cognitive abilities and moral reasoningof 10-year-olds. A social psychologist might summarize the results ofresearch about how children are affected by watching violence on television orin video games. But, in court, the essential questions must be: “Why did this boykill another child?” and “What should happen to reform or punish this boy?”A related point is that, “the law emphasizes the application of abstract principlesto specific cases” (Carroll, 1980).
Lawyers, plaintiffs, and defendants cannotbring an idea to court and ask the court for a ruling. They must bring aspecific case with particular characteristics. A ruling by a judge may set an importantnew precedent, but the immediate goal is to make a decision about aspecific case. Consequently, the law evolves one case at a time. The law’s emphasison the individual defendant or plaintiff explains why courts have beenmore receptive to clinical psychologists than to other types of psychologists. Cliniciansexamine and draw conclusions about a particular person. Like lawyers,they are oriented toward the individual case.Methods: Rulings versus DataThe law is based on authority; psychology is based on empiricism (Goldberg,1994).
Whereas law advances through the accumulation of rulings producedby courts, psychology advances through the accumulation of data produced byscientists.Because cultures differ in the amount of deference and obedience given topeople in positions of authority, this dimension (sometimes called “power distance”)is often used to differentiate cultures. The legal system is explicitly hierarchical(i.e., it would rank high on power distance). If a court of appealsoverrules the decision of a lower court, the lower court must accept the ruling.