Monday, March 08, 2004

Science and Psychology

Today's New York Times is running an article by Erica Goode on academic psychologists who are challenging the empirical basis for a number of common therapeutic tools and diagnoses, ranging from Rorschach tests to Munchausen's syndrome by proxy. The basic underlying debate is nothing new, of course. Psychology may be one of those fields that is defined more by its common objects of study than by any consensus on methods, and there has long been tension between proponents of rigorous quantitative and empirical methods versus psychologists favoring "softer" approaches.

The truth may be that one needs the right tools for the particular job at hand. It is legitimate, on the one hand, to try to test the efficacy of therapeutic measures through empirical methods, if only because ineffective therapies are useless at best and dangerous at worst. On the other hand, not every important aspect of human thought or behavior is easily amenable to scientific or quantitative analysis, and both medical and psychological interventions sometimes require practitioners to take steps that have often proved successful in the past, even though we may not fully understand why they work, when they do.

By what standards, then, should psychological claims be judged? That question is complex, and certainly it cannot be resolved by any simplistic nostrums we might inscribe in a web log. One proposition seems fair, however. Psychological theories and techniques should be tested against scientific standards whenever their proponents claim scientific status for them. That claim is often tacitly made, it seems to us, when a litigant is placed in some diagnostic category. If, for example, a mother in a custody battle faces testimony that she is afflicted by Munchausen's by proxy, the force of the testimony goes beyond mere allegations that she has subjected her children to medical abuse in the past and could therefore repeat that conduct. It suggests in addition that her future behavior is likely to be governed by a recognized mental health condition, and may be predicted by reference to features objectively associated with that condition. If we are to engage in the business of screening expert testimony at all, then before such testimony is permitted, it seems reasonable to demand some degree of rigorous empirical support for the condition's actual objective existence -- i.e., some showing that the "condition" amounts to more than fancy nomenclature for a recurrent pattern of human conduct, invented by some psychiatrist on a quiet day at the office. The same might be said, no doubt, of various modern "syndromes" offered in exculpation of misconduct.
Fed. R. Evid. 702: If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.