Encyclopedia of Psychology and Law

demonstration of the power of situations—especially

extreme institutional settings such as prisons—to shape

and control the behavior of the persons placed inside

them. Its results give lie to the notion that extreme social

behavior can only—or even mostly—be explained by the

extreme characteristics of persons who engage in it. The

SPE counsels us to look instead to the characteristics of

the settings or situations in which the behavior occurs. It

also stands as a challenge to what might be termed the

“presumption of institutional rationality”—that is, the

tendency to assume that institutions operate on the basis

of an inherent rationality that should be accepted rather

than questioned. Instead, the SPE (itself the most “irra-

tional” of prisons, in the sense that the guards had no legal

authority over the prisoners, who in turn, had committed

no crimes that warranted their punishment) suggests that

a kind of “psycho-logic” may operate in these settings,

which controls role-bound behavior, whether or not that

behavior actually furthers legitimate goals.

A recent detailed chronology of the events that tran-

spired in the SPE from initial city police arrests through

final termination is provided in Zimbardo’s book,The

Lucifer Effect: Understanding How Good People Turn

Bad.The story unfolds in the present tense, first-person

narrative for 8 chapters, with subsequent chapters dis-

cussing the ethics of such research, presenting its vari-

ous data sources, and then setting that study in a broader

context of other social science research that also demon-

strates the power of social situations to influence or

dominate individual behavior (additional information is

available at http://www.luciferEffect.com). All original data

and forms have been stored at the archives of the History

of American Psychology in Akron, Ohio.

Craig Haney and

Philip G. Zimbardo

See alsoJuvenile Boot Camps; Prison Overcrowding;

Supermax Prisons

Further Readings

Haney, C. (1999). Reflections on the Stanford Prison

Experiment: Genesis, Transformations, Consequences

(“The SPE and the Analysis of Institutions”). In T. Blass

(Ed.),Obedience to authority: Current perspectives on the

Milgram paradigm(pp. 221–237). Hillsdale,

NJ: Lawrence Erlbaum.

Haney, C. (2006). Reforming punishment: Psychological

limits to the pains of imprisonment.Washington, DC:

American Psychological Association Books.

Haney, C., Banks, C., & Zimbardo, P. (1973). Interpersonal

dynamics in a simulated prison. International Journal of

Criminology and Penology,1, 69–97.

Haney, C., & Zimbardo, P. (1977). The socialization into

criminality: On becoming a prisoner and a guard. In

J. Tapp & F. Levine (Eds.),Law, justice, and the

individual in society: Psychological and legal issues

(pp. 198–223). New York: Holt, Rinehart, and Winston.

Haney, C., & Zimbardo, P. (1998). The past and future

of U.S. prison policy: Twenty-five years after

the Stanford prison experiment. American Psychologist,

53,709–727.

Zimbardo, P. (2007). The Lucifer effect: Understanding how

good people turn bad.New York: Random House.

STATEMENTVALIDITY

ASSESSMENT(SVA)

Statement Validity Assessment (SVA) is a tool

designed to determine the credibility of child wit-

nesses’ testimonies in trials for sexual offenses. SVA

assessments are accepted as evidence in some North

American courts and in criminal courts in several

West European countries. The tool originated in

Sweden and Germany and consists of four stages.

Much of the SVA research is concerned with the abil-

ity of Criteria-Based Content Analysis (CBCA), one

of the four SVA stages, to discriminate between truth

tellers and liars. The Validity Checklist, another stage

of the SVA procedure, has also attracted attention

from researchers.

That a technique has been developed to verify

whether a child has been sexually abused is not sur-

prising. It is often difficult to determine the facts in an

allegation of sexual abuse, since often there is no med-

ical or physical evidence. Frequently, the alleged vic-

tim and the defendant give contradictory testimony,

and often, there are no independent witnesses to give

an objective version of events. This makes the per-

ceived credibility of the defendant and alleged victim

important. The alleged victim is in a disadvantageous

position if he or she is a child, as adults have a ten-

dency to mistrust statements made by children.

SVA consists of four stages: (1) a case-file analy-

sis; (2) a semistructured interview; (3) a CBCA that

systematically assesses the quality of a statement; and

(4) an evaluation of the CBCA outcome via a set of

questions (Validity Checklist).

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