Frye v. United States: The Case That Banned Lie Detectors From Courts

In 1923, James Alphonzo Frye was convicted of murder in Washington D.C. His defense had tried to introduce evidence from a "systolic blood pressure deception test" — an early precursor to the polygraph — to support his claim of innocence. The court refused to admit it.

The resulting appeals court ruling, Frye v. United States, created a legal standard that would govern the admission of scientific evidence in American courts for seven decades.

THE FRYE STANDARD: The court held that for scientific evidence to be admitted at trial, the underlying scientific method must be "sufficiently established to have gained general acceptance in the particular field in which it belongs."

In other words: if the relevant scientific community doesn't accept it, courts won't admit it.

WHY IT MATTERED: The Frye Standard was the first time American courts attempted to establish a principled basis for separating reliable from unreliable scientific testimony. Before Frye, courts had little framework for evaluating expert claims.

THE POLYGRAPH: Ironically, the lie detector that prompted the Frye ruling has never achieved general scientific acceptance. Despite being used by law enforcement agencies worldwide for pre-employment screening and criminal investigations, polygraph results remain inadmissible in most U.S. courtrooms under Frye and its successor standard. The scientific consensus holds that polygraphs are insufficiently reliable to be used as evidence.

FRYE'S REPLACEMENT: In 1993, the Supreme Court replaced Frye with the Daubert standard (in most federal courts), shifting responsibility for evaluating scientific validity to trial judges. Many states retained Frye. The difference between the two standards continues to affect which expert testimony can be heard in American courts.

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