In studying 250 cases of the wrongly convicted, Brandon Garrett explains why we should sometimes be wary of detailed confessions:
Of those 40 exonerees who confessed, for instance, 14 were mentally disabled or borderline mentally disabled, and three more (at least) were mentally ill. Thirteen of the 40 were juveniles. All but four were interrogated for more than three hours at a sitting. Seven described their involvement in the crime as coming to them in a "dream" or "vision." Seven were told they had failed polygraph tests. Like [Frank] Sterling, all of them waived their Miranda rights. Despite all these hints that their confessions were lengthy and coercive, and despite the fact that they were mostly vulnerable individuals, none had any luck challenging their confessions before trial. The confessions were thought to be such powerful evidence of guilt that eight were convicted despite DNA tests at trial that in fact excluded them as the culprit.