"He just isn't very smart"

As he did during the pre-trial suppression hearing, psychologist Robert Berland testified that John Couey is both mentally ill and mildly mentally retarded.

The defendant has a "psychotic disturbance" characterized by delusions, hallucinations and a mood disturbance, Berland said. On a recent IQ test he scored a 64; 70 is generally the cutoff for retardation.

This led Berland to address the incriminating statements Couey made to jail guards.

"His judgment of course is impaired because he's not very smart," Berland explained.

Couey's retardation, mental illness and isolation from other prisoners combined to make him more susceptible to subtle methods of interrogation. Though they may not have realized it, guards did employ such methods -- reinforcement, rewards, isolation -- and Berland said he found similar tactics in a Department of Defense manual.

-- Elena Lesley