Criminal Psychology: A Manual for Judges, Practitioners, and Students

by Hans Gross

Let us first consider the whole trial.

The effect is here the evidence of A’s guilt. The complex conditions for its establishment are the collective instruments in getting evidence; the individual conditions are to be established by means of the individual sources of evidence—testimony of witnesses, examination of the premises, obduction, protocol, etc.

The constantification of conditions now consists in standardizing the present instance, thus: Whenever similar circumstances are given, i.e.: the same instruments of evidence are present, the evidence of guilt is established. Now the accompanying changes with regard to the effect, i.e.: proof of guilt through evidence, have to be tested—therefore the individual conditions—i.e.: the individual sources of evidence have to be established and their values to be determined and varied. Finally, the accompanying change in effect (conviction by evidence) is to be tested. The last procedure requires discussion; the rest is self evident. In our business isolation is comparatively easy, inasmuch as any individual statement, any visual impression, any effect, etc., may be abstracted without difficulty. Much harder is the determination of its value. If, however, we clearly recognize that it is necessary to express the exact value of each particular source of evidence, and that the task is only to determine comparative valuation, the possibility of such a thing, in at least a sufficiently close degree of certainty, must be granted. The valuation must be made in respect of two things—(1) its reliability (subjective and relative); (2) its significance (objective and absolute). On the one hand, the value of the evidence itself must be tested according to the appraisement of the person who presents it and of the conditions under which he is important; on the other, what influence evidence accepted as reliable can exercise upon the effect, considered in and for itself. So then, when a testimony is being considered, it must first be determined whether the witness was able and willing to speak the truth, and further, what the importance of the testimony may be in terms of the changes it may cause in the organization of the case.

Of greatest importance and most difficult is the variation of conditions and the establishment of the changes thereby generated, with regard to the effect,—i.e.: the critical interpretation of the material in hand. Applied to a case, the problem presents itself in this wise: I consider each detail of evidence by itself and cleared of all others, and I vary it as often as it is objectively possible to do so. Thus I suppose that each statement of the witness might be a lie, entirely or in part; it might be incorrect observation, false inference, etc.—and then I ask myself: Does the evidence of guilt, the establishment of an especial trial, now remain just? If not, is it just under other and related possible circumstances? Am I in possession of these circumstances? If now the degree of apparent truth is so far tested that these variations may enter and the accusation still remain just, the defendant is convicted: but only under these circumstances.

The same procedure here required for the conduct of a complete trial, is to be followed also, in miniature, in the production of particulars of evidence. Let us again construe an instance. The effect now is the establishment of the objective correctness of some particular point (made by statements of witnesses, looks, etc.). The complex of conditions consists in the collection of these influences which might render doubtful the correctness—i.e., dishonesty of witnesses, defective examination of locality, unreliability of the object, ignorance of experts, etc. It is necessary to know clearly which of these influences might be potent in the case in hand, and to what degree. The standardization consists, also this time, in the comparison of the conditions of the present case with those of other cases. The variation, again, consists in the abstraction from the evidence of those details which might possibly be incorrect, thus correcting it, from various points of view, and finally, in observing the effect as it defines itself under this variety of formulation.

This procedure, adopted in the preparation and judgment of each new piece of evidence, excludes error as far as our means conceivably permit. Only one thing more is needful—a narrow and minute research into that order of succession which is of indispensable importance in every natural science. “Of all truths concerning natural phenomena, those which deal with the order of succession are for us the most important. Upon a knowledge of them is grounded every intelligent anticipation of the future” (J. S. Mill).[48] The oversight of this doctrine is the largest cause of our failures. We must, in the determination of evidence, cleave to it. Whenever the question of influence upon the “effect” is raised, the problem of order is found invariably the most important. Mistakes and impossibilities are in the main discovered only when the examination of the order of succession has been undertaken.

In short: We have confined ourselves long enough to the mere study of our legal canons. We now set out upon an exact consideration of their material. To do this, obviously demands a retreat to the starting-point and a beginning we ought to have made long ago; but natural sciences, on which we model ourselves, have had to do the identical thing and are now at it openly and honestly. Ancient medicine looked first of all for the universal panacea and boiled theriac; contemporary medicine dissects, uses the microscope, and experiments, recognizes no panacea, accepts barely a few specifics. Modern medicine has seen the mistake. But we lawyers boil our theriac even nowadays and regard the most important study, the study of reality, with arrogance.

Topic II. PSYCHOLOGIC LESSONS.

Section 3. (a) General Considerations.

Of the criminalist’s tasks, the most important are those involving his dealings with the other men who determine his work, with witnesses, accused, jurymen, colleagues, etc. These are the most pregnant of consequences. In every case his success depends on his skill, his tact, his knowledge of human nature, his patience, and his propriety of manner. Anybody who takes the trouble, may note speedily the great differences in efficiency between those who do and those who do not possess such qualities. That they are important to witnesses and accused is undoubted. But this importance is manifest to still others. The intercourse between various examining judges and experts is a matter of daily observation. One judge puts the question according to law and expects to be respected. He does not make explicit how perfectly indifferent the whole affair is to him, but experts have sufficient opportunity to take note of that fact. The other narrates the case, explains to the experts its various particular possibilities, finds out whether and what further elucidation they demand, perhaps inquires into the intended manner and method of the expert solution of the problem, informs himself of the case by their means, and manifests especial interest in the difficult and far too much neglected work of the experts. It may be said that the latter will do their work in the one case as in the other, with the same result. This would be true if, unfortunately, experts were not also endowed with the same imperfections as other mortals, and are thus far also infected by interest or indifference. Just imagine that besides the examining magistrate of a great superior court, every justice and, in addition, all the chiefs and officials manifested equal indifference! Then even the most devoted experts would grow cool and do only what they absolutely had to. But if all the members of the same court are actuated by the same keen interest and comport themselves as described, how different the affair becomes! It would be impossible that even the indifferent, and perhaps least industrious experts, should not be carried out of themselves by the general interest, should not finally realize the importance of their position, and do their utmost.