From The elements of crime by Boris Brasol, 1927

”The main difficulty about the present method of procedure is that it is not in fact what it pretends to be. The method of trial of a criminal case before a jury is in the nature of a combat in which two opposing forces are lined up against each other and the battle goes to the strongest. The judge acts as a sort of referee whose business it is to prevent fouls and the taking of unfair advantages. Now into the arena where this battle is taking place the expert witness is introduced. He is hired and paid by one of the parties to the issue, his direct testimony is given in response to the attorney representing that party. The attorney representing the opposite side then undertakes to tear to pieces the contributions to the evidence which he has made in favor of the side for which he was employed. This is essentially and fundamentally a partisan conflict, and the expert witness is asked to do something that society does not ask of a man in any other capacity. It asks him to reserve the same judicial attitude of mind which is expected of the judge on the bench and to answer all questions fairly and impartially and free from prejudice.”²³

Herein, perhaps, lies the psychological explanation of the negative attitude frequently evinced by the jurors with respect to testimony in general and alienists’ opinions in particular. If, as Dr. White remarks : “ the whole trial is nothing but a partisan conflict,” the two opposing camps staging sensation tournaments with hired psychiatrists wasting their skill on befogging the issue, it is not surprising that the jurors should often be tempted to ignore altogether this particular element of the criminal trials.

    ²³ Dr. William A. White, “Insanity and the Criminal Law,” p. 56, New York, 1923.

The elements of crime(psycho-social interpretation) by Boris Brasol
... with introductions by John H. Wigmore ... and William A. White ...
New York, London [etc.] Oxford University Press, 1927, pages 321-2.