Supplement to Chapter 6

(The General Acceptance Standard)

Copyright © 2001 DH Kaye

FELDMAN, Justice.

Applying the rule of Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), the trial judge entered an order precluding "expert testimony of Plaintiff's alleged repressed memory." We granted review to clarify Rule 702, Arizona Rules of Evidence, which governs the admission of opinion testimony. * * *

FACTS AND PROCEDURAL HISTORY

Kim Logerquist (Plaintiff) alleges that her pediatrician (Defendant) sexually abused her on several occasions between 1971 and 1973, when she was eight to ten years old. Plaintiff further alleges that she had amnesia about those events until 1991, when her memory was triggered by watching a television commercial featuring a pediatrician. She sought "to introduce evidence, through expert testimony, that severe childhood trauma, including sexual abuse, can cause a repression of memory, and that in later years this memory can be recalled with accuracy."

Over objection, the trial judge granted Defendant's motion that a Frye hearing be held to assess the admissibility of expert testimony regarding repressed memory. Two experts testified at this hearing. Plaintiff called Dr. Bessell van der Kolk, a clinical psychiatrist who specializes in dissociative amnesia. He testified regarding the large number of patients who alleged such phenomenon and about his diagnoses of dissociative amnesia or post-traumatic stress disorder in such patients. He would testify, among other things, that his experience and observations over many years, together with the extensive literature on the subject, have led him to conclude the phenomenon exists in some patients. Defendant's expert, Dr. Richard Kihlstrom, a research psychologist, testified there were serious flaws in the many studies supporting repressed memory and cited other studies finding trauma usually enhances memory rather than causes amnesia. Doctor Kihlstrom did not, however, have any personal experience treating or dealing with people claiming to suffer from repressed memory; nor had he participated in any studies on trauma's effect on memory.

After a lengthy hearing, the trial judge determined the "theories advanced by Plaintiff's experts are not generally accepted in the relevant scientific community of trauma memory researchers." The judge therefore "ORDERED excluding expert testimony of Plaintiff's alleged repressed memory, and Plaintiff's theory that such evidence can be recalled with accuracy."

Because this interlocutory order was not appealable, Plaintiff sought review by special action in the court of appeals. The court of appeals declined jurisdiction, and Plaintiff sought review by this court. We granted review * * * , allowed supplemental briefing, and heard oral argument. The first question accepted for review was whether Frye * * * applied. We conclude Frye was inapplicable * * * . We now vacate the order excluding expert testimony.

DISCUSSION

A. Contentions of the parties

Plaintiff contends the [trial court's] Order, based on the Frye principle, is incorrect because Frye is inapplicable. If the Frye test were applicable to the evidence Plaintiff seeks to adduce, Plaintiff argues that it should be discarded in favor of Daubert's test of reliability [see infra chapter 7]. Defendant, on the other hand, believes that Frye applies to the testimony and the trial judge correctly concluded the principles explained by Doctor van der Kolk had not gained general acceptance, so that expert testimony regarding these principles was therefore inadmissible. * * *

B. Proceedings in the trial court

We think it necessary to focus on the precise controversy as defined by the record before the trial court. Plaintiff's complaint, filed more than twenty years after the incidents and ten years after Plaintiff became an adult, initially raised questions regarding timeliness. The trial judge first granted Defendant's motion to dismiss on the basis that the action was barred by the statute of limitations. Our court of appeals reversed that order, without resolving the Frye issue, and remanded for proceedings not inconsistent with its opinion. We denied review, with Justice Martone voting to grant.

On remand, and after extensive discovery, Defendant filed a Motion for Evidentiary Hearing Pursuant to Frye v. United States (hereafter Frye Motion). Defendant argued that Plaintiff's case is based on scientific theories that are not readily accepted by the medical and scientific communities. Further, he contended the memories alleged were not real or accurate but had been distorted, implanted, or suggested by improper techniques used by the physician and psychologist treating Plaintiff for emotional problems. Because the "medical community is unwilling to make a statement that there is scientific foundation for the accuracy of Ms. Logerquist's claims, it would be inappropriate to allow her to proceed forward to trial."

In response, Plaintiff objected to a Frye hearing. As permitted by Ariz. R. Evid. 702, Plaintiff's treating doctors would testify to experience and observation with this and many other cases dealing with repressed memory, dissociative amnesia, and post-traumatic stress disorder. Even if they gave general testimony based on the literature covering the subject, and if such testimony were subject to Frye, they could show general acceptance need not be non-controversial or universal. Conceding that not all allegedly recovered memories are accurate or truthful, Plaintiff argued that the question of the accuracy and credibility of her recollection was for the jury.

In his reply to Plaintiff's response to the Frye Motion, Defendant argued that:

Plaintiff alleges she suffers from dissociative amnesia.... The manual in which 'Dissociative Amnesia' is defined also indicates:

There are no tests or set of procedures that invariably distinguish Dissociative Amnesia from Malingering, but individuals with Dissociative Amnesia usually score high on standard measures of hypnotizability and dissociative capacity. Malingered amnesia is more common in individuals presenting with acute, florid symptoms in a context in which potential secondary gain is evident--for example, financial or legal problems....

Care must be exercised in evaluating the accuracy of retrieved memories, because the informants are often highly suggestible. There has been considerable controversy concerning amnesia related to reported physical or sexual abuse, particularly when abuse is alleged to have occurred during early childhood. Some clinicians believe that there has been an underreporting of such events, especially because the victims are often children and perpetrators are inclined to deny or distort their actions. However, other clinicians are concerned that there may be overreporting, particularly given the unreliability of childhood memories. There is currently no method for establishing with certainty the accuracy of such retrieved memories in the absence of corroborative evidence.

These pleadings were followed by a veritable blizzard of paper. Having received a witness list naming Doctor van der Kolk as Plaintiff's independent (non-treating) expert, Defendant sought by motion to preclude Doctor van der Kolk from testifying about the results of animal studies. A separate motion sought to preclude the doctor from giving any testimony that relied on his own clinical experience. These were accompanied by a motion to preclude Doctor van der Kolk from relying on the literature listed in his letter to Plaintiff's counsel. Defendant also moved to preclude the testimony of Plaintiff's treating doctors, sought an order permitting him to provide additional material to assist the court in its evaluation of Doctor van der Kolk's testimony, and moved to strike an affidavit filed in opposition to Defendant's motion for summary judgment because it contained expert opinion.

Defendant argued that expert opinion was inadmissible, no matter what its basis or the subject to which it was directed--whether repressed memory, dissociative amnesia, or post-traumatic stress disorder. Defendant maintained that view in arguing to this court. Plaintiff's position, on the other hand, was set forth in her response to Defendant's Memorandum to Assist the Court in Evaluating the Admissibility of Expert Evidence:

This Response shows that Dr. van der Kolk's personal experiences and observations in treating hundreds of survivors of childhood sexual abuse (CSA) that have total or partial amnesia of the CSA are not subject to the Frye rule. The Response will further show that Dr. van der Kolk should be allowed to testify ... that when some CSA victims do have delayed memories, that their memories are as reasonably accurate as normal memories, if not better.

Doctor van der Kolk's February 8, 1998 letter to counsel gives an even better picture of what Defendant sought to preclude:

I hereby accept you[r] invitation to testify.... I intend to testify that amnesia for traumatic experiences, including for sexual abuse, has been documented in numerous scientific reports for over a century, and that this notion is, in fact, so well accepted in the relevant scientific community that it has not only been incorporated in the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association within the very criterion set for Post Traumatic Stress Disorder, but also under a separate rubric of Dissociative Amnesia. It has been further amplified in the official statement of the American Psychiatric Association on Memories of Childhood Sexual Abuse. I am the Director of the Trauma Center in Brookline, MA, which specializes in the treatment and research of individuals who suffer from the psychological effects of trauma. I have conducted numerous studies on the nature of the human response to trauma, including specifically on memory processes in responses.

The letter then listed some of the articles and books Doctor van der Kolk planned to rely on in his testimony. The extensive bibliography that followed has been described in footnote 2, supra. Included were cites to seven items written by Doctor van der Kolk himself. Almost all were articles published in prestigious, peer-reviewed journals such as the HARVARD REVIEW OF PSYCHIATRY and the AMERICAN JOURNAL OF PSYCHIATRY. Doctor van der Kolk's qualifications were also of record. They clearly establish his extensive education, training, and experience in psychology and psychiatry and specifically in the study and treatment of dissociative amnesia.

It is apparent we are not dealing with an alchemist attempting to change lead into gold or an astrologer predicting events from the movements of the stars but one of the leading researchers and authorities in behavioral science. It would be strange that a witness so well qualified and experienced would not be permitted to testify on an issue beyond the experience of the average juror. Nevertheless, the trial judge's Order was quite broad. He first cited to DSM-IV § 300.12 "to support [Plaintiff's] contention that dissociative amnesia is generally accepted in the relevant scientific community." However, the judge noted, that same section provides the cautionary note previously quoted * * * . After reviewing similar cautionary notes in other studies, the judge concluded:

Finally, this Court has carefully considered the various studies relied upon by Plaintiff's expert. Studies in the area of the effect of trauma upon memory are in their infancy. This Court has concluded that these studies contain serious methodological flaws, and that these flaws have prevented Plaintiff's theory from being generally accepted in the relevant scientific community of trauma memory researchers. These methodological flaws include, but are not limited to, inadequate sample sizes, gender bias, consideration of other reasons for loss of memory (i.e., infantile amnesia), and perhaps most importantly, independent corroboration that the event alleged to have been forgotten, actually occurred.

For the reasons set forth above, this Court has concluded that the theories advanced by Plaintiff's experts are not generally accepted in the relevant scientific community of trauma memory researchers. Therefore,

IT IS ORDERED excluding expert testimony of Plaintiff's alleged repressed memory, and Plaintiff's theory that such evidence can be recalled with accuracy.

As Defendant indicated at argument, this order not only precluded Doctor van der Kolk's testimony but effectively precluded that of Plaintiff's treating physicians. Even assuming Plaintiff would be allowed to testify about her memory, this left her in the pragmatically impossible situation of having no evidence to support her testimony but nevertheless having to persuade the jury that she had suffered dissociative amnesia and that her recall could have been accurate. On the other hand, Defendant would presumably be able to call his expert to testify that Plaintiff's recollection was incredible or, at best, inaccurate. The preclusion order, in other words, as effectively took the case from the jury as if the judge had granted summary judgment or directed a verdict. We turn, therefore, to consider the legal propriety of the Order.

C. Was Frye properly applied

By its own words, Frye applies to the use of novel scientific theories or processes to produce results. At the outset, we note that neither Plaintiff nor her lawyers argue that any scientific principle or process can be used to produce memories that are always or often accurate. As a matter of scientific principle, one may now say that E always equals MC², but Plaintiff does not claim that some scientific process, theory, or formula may be applied to test whether her memories of having been molested are true and accurate or whether the memories were imagined, suggested, implanted, or even, to put it tactfully, invented. One may or may not believe Plaintiff. The effect of the Order is to practically ensure Plaintiff's testimony will not be believed because she will not be allowed to present expert evidence to describe or support the possible existence or diagnosis of repressed memory or dissociative amnesia.

We believe, however, that the truth of Plaintiff's testimony that she actually and accurately recalled or remembered the events, as distinguished from inventing them or having had them suggested or implanted, is for a jury to decide. While Defendant contends the alleged loss of memory and consequent delay in reporting make Plaintiff's testimony unworthy of belief, in this, as in other cases, Rule 702 allows Plaintiff to call expert witnesses to explain her behavior following the events alleged and to help the jury determine whether Plaintiff's memories are real and accurate or imagined. We have so held on just such issues in the criminal law.

In State v. Lindsey, for example, we dealt with the question of expert testimony regarding "behavior patterns of victims of 'in-home incestuous-type [child] molesting.' " 149 Ariz. 472, 473, 720 P.2d 73, 74 (1986). The court of appeals noted that the evidence was offered to explain why child victims of incest may not reveal the events until long after the occurrence and why they may recant. State v. Lindsey, 149 Ariz. 493, 495-96, 720 P.2d 94, 96-97 (App.1985). The trial judge overruled defendant's Frye objection to the opinion evidence. Lindsey, 149 Ariz. at 476, 720 P.2d at 77. The Martone dissent makes much of the fact that the expert testimony was based on "recognized principles of social and behavioral science." But Doctor vander Kolk's testimony is similarly based on principles of social and behavioral science recognized by clinicians. There was no Frye hearing in Lindsey. Defendant's Frye objection was overruled because the judge "determined Doctor Baker was qualified to testify because she had practiced" in the field, "saw patients" suffering from child sexual abuse, consulted with state agencies and case workers, and made "decisions and plans on specific cases [as well as doing] psychological evaluation of child victims and [having] seen over 100 victims, mostly in the family-type situation." Id. at 497, 720 P.2d at 98. We had the following comment regarding the propriety of admitting such testimony:

The trial judge has discretion to allow such expert testimony [under Rule 702] where it may assist the jury in deciding a contested issue, including issues pertaining to accuracy or credibility of a witness' recollection or testimony. The trial judge may exercise this discretion where there is a reasonable basis to believe that the jury will benefit from the assistance of expert testimony that explains recognized principles of social or behavioral science which the jury may apply to determine issues in the case. Testimony of this type is not to be permitted in every case, but only in those where the facts needed to make the ultimate judgment may not be within the common knowledge of the ordinary juror.

[T]he court of appeals correctly concluded that the trial court did not abuse its discretion in permitting ... testimony on general patterns of behavior. We cannot assume that the average juror is familiar with the behavioral characteristics of victims of child molesting. Knowledge of such characteristics may well aid the jury in weighing the testimony of the alleged child victim. Children who have been the victims of sexual abuse or molestation may exhibit behavioral patterns (e.g. recantation, conflicting versions of events, confusion or inarticulate descriptions) which jurors might attribute to inaccuracy or prevarication, but which may be merely the result of immaturity, psychological stress, societal pressures or similar factors as well as of their interaction.

Id. at 473-74, 720 P.2d at 74-75 (citations omitted); see also State v. Moran, 151 Ariz. 378, 728 P.2d 248 (1986).

In State v. Roscoe, we again dealt with behavioral evidence, though of a much different sort. We held a dog handler's opinion on the alleged ability of his tracking dog to identify scent long after it was laid down was admissible and Frye inapplicable. 145 Ariz. 212, 219-20, 700 P.2d 1312, 1319-20 (1984). We explained:

The evidence here was not bottomed on any scientific theory. In fact, it appears that no one knows exactly how or why some dogs are able to track or scent, or the degree to which they are able to do so. No attempt was made to impress the jury with the infallibility of some general scientific technique or theory. Rather, this evidence was offered on the basis that it is common knowledge that some dogs, when properly trained and handled, can discriminate between human odors. Preston's testimony was premised upon this simple idea and was not offered as a product of the application of some accepted scientific process, principle, technique or device. It was offered as Preston's opinion of the meaning of his dog's reaction; that opinion was based upon Preston's training of and experience with the dog. The weight of the evidence did not hinge upon the validity or accuracy of some scientific principle; rather, it hinged on Preston's credibility, the accuracy of his past observation of the dog's performance, the extent of the training he had given the dog, and the reliability of his interpretations of the dog's reactions. It was not the theories of Newton, Einstein or Freud which gave the evidence weight; if so, the Frye test should have been applied. It was, rather, Preston's knowledge, experience and integrity which would give the evidence weight and it was Preston who was available for cross-examination. His credentials, his experience, his motives and his integrity were effectively probed and tested. Determination of these issues does not depend on science; it is the exclusive province of the jury.

Id. (citations omitted); see also Brooks v. Colorado, 975 P.2d 1105 (Colo.1999) (similar experience-based testimony subject to Rule 702 analysis, not Frye); Louisiana v. Catanese, 368 So.2d 975 (La.1979) (excluding polygraph evidence using equivalent of Ariz. R. Evid. 702). It turned out that the witness presenting the dog-scent evidence in Roscoe was a charlatan. See State v. Roscoe, 184 Ariz. 484, 910 P.2d 635 (1996) (Roscoe II). But neither Rule 702 (with or without Frye), * * * nor any other system can guarantee the validity of any particular evidentiary ruling. Just as the refusal to apply Frye to Preston's dog-scent evidence led to the admission of false testimony, so the application of Frye * * * could well have led to the exclusion of testimony from Einstein or Freud, both of whom advanced theories not generally accepted for many years. See CLIFFORD M. WILL, WAS EINSTEIN RIGHT? (1986).

In State v. Hummert, we held that expert opinion on probability percentages based on computations derived from DNA statistics was inadmissible under Frye because the statistical bases and resultant formulae applied to reach the conclusion were not yet generally accepted. The expert's opinion-- the final result--was based on a process or formula established by others and not generally acknowledged by scientists and statisticians in that field. 188 Ariz. 119, 124-25, 933 P.2d 1187, 1192-93 (1997). But we also held that the expert could relate his experience in the field to the facts and that an opinion based on his observations and experience would be admissible. Id. at 125, 933 P.2d at 1193. This was not, as the Martone dissent claims, because the DNA principle passed the Frye test. It was, rather, because the opinions offered on random match frequency, while not generally accepted, passed the Ariz. R. Evid. 702 test of witness observation and experience. We explained:

The experts' testimony in the present case involved two types of evidence-- scientific evidence on the procedures for determining a match between evidentiary DNA and opinion evidence concerning the experts' experience with random matches. The trial judge properly applied the Frye analysis and determined that evidence of a match is admissible. However, on the basis of the scientific evidence then available, the judge did not allow the experts to testify about the mathematical or statistical probability resulting from the match. Instead, the experts were allowed to offer evidence of their personal opinion. This testimony is governed not by the application of Frye but by Arizona Rules of Evidence 702 and 703. "Frye-ing" scientific evidence is necessary when application of a scientific technique is "likely to have an enormous effect in resolving completely a matter in controversy." However, when the expert gives testimony that "only helps a trier to interpret the evidence ... it will be received on a lesser showing of scientific certainty." As we stated in Roscoe, "[t]he weight of the evidence did not hinge upon the validity or accuracy of some scientific principle; rather, it hinged on [the expert's] credibility, the accuracy of his past observation ... the extent of the training ... and the reliability of his interpretations...." The experts in this case did not testify to conclusions based on the application of Cellmark's statistics and database but only to their own experience. Having made the DNA examination according to recognized scientific principles and finding a match at three loci, the experts claimed that because of the unique nature of each person's DNA, they had never before seen a three- loci match from unrelated individuals. On the basis of their own experience, they believed such a random match would be very uncommon. The trial judge did not err in admitting this evidence of the experts' own work and experience and the opinions reached on that basis. See Ariz. R. Evid. 702 and 703.

Id. at 124-25, 933 P.2d at 1192-93 (citations omitted).

Many cases in our courts, and in those of other states with rules similar to our Ariz. R. Evid. 702, reach similar conclusions in dealing with expert opinion in matters of behavioral science. Our court of appeals concluded that Frye was inapplicable to expert testimony on child sexual abuse accommodation syndrome (CSAAS). State v. Varela, 178 Ariz. 319, 873 P.2d 657 (App. 1993). The court remarked that "testimony concerning general characteristics of child sexual abuse victims is not 'new, novel or experimental scientific evidence' and therefore does not require the additional screening provided by Frye." Id. at 325-26, 873 P.2d at 663-64 (quoting People v. Stoll, 49 Cal.3d 1136, 265 Cal. Rptr. 111, 783 P.2d 698, 714 (1989)); see also State v. Tucker, 165 Ariz. 340, 346, 798 P.2d 1349, 1355 (App. 1990) (behavioral characteristics of child molesters and victims); State v. Stowers, 81 Ohio St.3d 260, 690 N.E.2d 881 (1998) (Frye inapplicable to expert's testimony that alleged child victim's behavior, including delayed disclosure and recantation, is consistent with behavior expert observed in victims of CSAAS).

Of course in Varela and Tucker, as in the other cases cited, the testimony was not offered as direct proof that sexual abuse occurred but as an explanation of behavior that would help the jury understand the evidence and determine whether the charge was true. See also Frenzel v. Wyoming, 849 P.2d 741 (Wyo. 1993) (although CSAAS is not yet generally accepted and thus not admissible to prove sexual abuse actually occurred, expert testimony based on experience, observation, and literature may be admitted to explain behavior of alleged victim, including delayed reporting); cf. Lantrip v. Kentucky, 713 S.W.2d 816 (Ky.1986) (an example of cases holding CSAAS not generally accepted, therefore testimony inadmissible); see also Isely v. Capuchin Province, 877 F.Supp. 1055 (E.D. Mich. 1995) (evidence such as Dr. van der Kolk's admissible, but expert may not testify about victim's credibility).

We have reached similar conclusions in rape cases. In upholding a rape conviction based in part on psychiatric testimony regarding the way in which post-traumatic stress syndrome might have affected the victim's behavior, we noted that courts in other states disagreed on the admissibility of so-called rape trauma syndrome to prove the rape occurred but nevertheless concluded:

Although we might have some difficulty in upholding the admissibility of rape trauma syndrome to prove the existence of a rape, we believe, however, if properly presented by a person qualified by training and experience such as a psychiatrist or psychologist, that such evidence is admissible to show lack of consent. This testimony would not invade the province of the jury. The expert would be subject to cross-examination and the jury could then determine what weight the evidence is to receive.

State v. Huey, 145 Ariz. 59, 63, 699 P.2d 1290, 1294 (1985).

Other states have reached similar conclusions with regard to rape trauma syndrome. The California Supreme Court, for example, applied Frye and concluded that expert testimony was not admissible to prove that rape occurred. If factually relevant, however, it would have been admissible to explain behavior following the incident and to rebut popular misconceptions that might have given credence to a defendant's argument that the victim's delayed reporting or other behavior would justify an inference that rape had not occurred. California v. Bledsoe, 36 Cal.3d 236, 203 Cal.Rptr. 450, 681 P.2d 291, 298-99 (1984); see also Colorado v. Hampton, 746 P.2d 947, 949- 52 (Colo.1987) (collecting cases and holding that Frye test inapplicable when behavioral testimony offered to explain ninety-day reporting delay).

These principles are not limited to criminal cases. The same rationale is applied in cases involving medical causation and techniques. Gilkey v. Schweitzer, 295 Mont. 345, 983 P.2d 869 (1999) (evidentiary standards applicable to novel scientific evidence should not have been applied to preclude anesthesiologist's expert opinion that placement of catheter while patient was anesthetized increased risk of injury). In a recent case in which the operative facts are quite similar to those in this case, the court was required to decide whether a physician's testimony based on experience, observation, and study of literature was admissible on the question of whether stress could trigger otherwise asymptomatic multiple sclerosis. Colwell v. Mentzer Inv., Inc., 973 P.2d 631 (Colo. App. 1998). Refusing to apply Frye and using a version of Rule 702 identical to Arizona's, the court blended a number of theories but held the testimony should be admitted. The admissibility of such testimony should be determined by balancing

(1) the reliability of the scientific principles upon which the testimony rests, i.e., the potential to aid the jury in reaching an accurate resolution of a disputed issue, and (2) the likelihood that the introduction of the evidence may overwhelm or mislead the jury.

. . .

The reliability inquiry does not require a process of scientific "nose-counting." Rather, a court should consider factors such as the degree of acceptance in the scientific community, the novelty of the scientific principle, and the existence of specialized literature on the subject.

. . .

The expert's qualifications and expertise in the area of MS were not disputed, and the trial court determined that his testimony would be helpful to the trier of fact. His testimony did not involve the application of any novel or newly developed scientific device or process, nor did it involve the manipulation of physical evidence. Rather, it concerned his observations of thousands of cases of MS and review of studies by others.

Plaintiff's expert, a board certified neurologist, testified that he has been in practice for over 40 years. At the time of the trial he taught at Harvard Medical School and ran the multiple sclerosis project at the Beth Israel Hospital in Boston, Massachusetts. He testified that over the course of his career he had seen between 5,000 and 6,000 MS patients. In his opinion, certain kinds of stress in some patients with MS can trigger the appearance of symptoms in an asymptomatic patient....

The evidence presented at trial concerned the effect that stress could have in causing MS to become symptomatic. Such testimony would assist the trier of fact in understanding the evidence of what researchers in the field have discovered. Thus, the evidence satisfies the threshold inquiry.

Id. at 636-37 (citations omitted).

Finally, a recent California case directly on point puts the matter quite well. The plaintiffs claimed their memory of sexual abuse by their father and stepfather had been repressed and then fortuitously triggered. They offered expert evidence by a psychologist who specialized in the field of sexual abuse and memory. The California court refused to apply * * * Frye * * * and affirmed the trial judge's refusal to hold a Frye hearing, holding the judge correctly admitted the expert's opinion that the circumstances and plaintiffs' behavior were "consistent with other individuals who had repressed their memories of childhood sexual abuse." Wilson v. Phillips, 73 Cal. App. 4th 250, 86 Cal. Rptr. 2d 204, 206 (1999). The court explained:

California distinguishes between expert medical opinion and scientific evidence; the former is not subject to the special admissibility rule of Kelly-Frye. Kelly-Frye applies to cases involving novel devices or processes, not to expert medical testimony, such as a psychiatrist's prediction of future dangerousness or a diagnosis of mental illness.

Similarly, the testimony of a psychologist who assesses whether a criminal defendant displays signs of deviance or abnormality is not subject to Kelly-Frye.

Id. at 207 (quoting California v. Ward, 71 Cal.App.4th 368, 83 Cal. Rptr. 2d 828, 833 (1999) (Frye inapplicable to psychologist's opinion of defendant's propensity to repeat sexually violent behavior)). * * *

There are many more cases, with varying rationales and conclusions, but we extract and apply the same rule that our courts have previously applied in cases involving Ariz. R. Evid. 702. Opinion testimony on human behavior is admissible when relevant to an issue in the case, when such testimony will aid in understanding evidence outside the experience or knowledge of the average juror, and when the witness is qualified, as Ariz. R. Evid. 702 requires, by "knowledge, skill, experience, training, or education." To put it simply, Frye is inapplicable when a qualified witness offers relevant testimony or conclusions based on experience and observation about human behavior for the purpose of explaining that behavior. Of course, our cases forbid a witness from expressing an opinion on the alleged victim's credibility or the truth of allegations of sexual abuse or rape. This principle applies as well in the present case to Doctor van der Kolk's proposed testimony. Expert testimony is admitted to explain behavior that a party claims is consistent or inconsistent with the alleged event. As we said in Hummert:

Although compliance with Frye is necessary when the scientist reaches a conclusion by applying a scientific theory or process based on the work or discovery of others, under Rules 702 and 703 experts may testify concerning their own experimentation and observation and opinions based on their own work without first showing general acceptance. Such evidence need only meet the traditional requirements of relevance and avoid substantial prejudice, confusion, or waste of time.

188 Ariz. at 127, 933 P.2d at 1195; see also California v. McDonald, 37 Cal.3d 351, 208 Cal.Rptr. 236, 690 P.2d 709 (1984).

This does not mean, as the dissenters argue, that we believe the practice of medicine, including psychiatry, is not based on science. Rather, it means that expert evidence based on a qualified witness' own experience, observation, and study is treated differently from opinion evidence based on novel scientific principles advanced by others. As in the past, Frye continues to apply only to the latter. The Order applied Frye to prohibit observation- and experience-based expert testimony about recovered memory, no matter for what purpose offered. Insofar as it relied on Frye, the order was therefore overbroad and legally erroneous and must be vacated. * * *

The Martone dissent misstates and exaggerates our holding by prophecying that our refusal to apply Frye to Doctor van der Kolk's testimony means that "any expert" on human behavior can hereafter be allowed to testify to any theory, "however farfetched," without any showing of scientific reliability. Doctor van der Kolk is not any expert testifying to farfetched theories. As one glance at his curriculum vitae shows, he is a very experienced, well recognized, respected clinician with degrees in psychology and medicine. He is asked to testify to his experience and observation in caring for patients, such as Plaintiff, who report repressed memory of sexual abuse. We hold simply that he can be asked to testify to his opinions based on the results of his experience, his observations, his own research and that of others with which he is familiar, and the care of his patients. * * *

SUMMARY AND CONCLUSION

It is no doubt tempting, but potentially quite harmful, to exaggerate the breadth and scope of this decision to support erroneous predictions of the dire consequences that will follow. To compare the repressed memory controversy between clinical psychiatrists and psychologists on the one hand and research psychologists on the other to a debate over astrology is, to put it tactfully, quite a stretch. So is the fear that "any expert" can testify to any conclusion, no matter how scientifically unreliable. Our decision * * * does not turn on an attempt to determine whether repressed memory is "scientific" or "unscientific." Plaintiff does not claim her memories are proved true as a matter of scientific fact. Frye is applicable when an expert witness reaches a conclusion by deduction from the application of novel scientific principles, formulae, or procedures developed by others. It is inapplicable when a witness reaches a conclusion by inductive reasoning based on his or her own experience, observation, or research. In the latter case, the validity of the premise is tested by interrogation of the witness; in the former case, it is tested by inquiring into general acceptance.

This case turns on a non-scientific issue. As the Martone dissent concedes:

In many respects, the phenomenon of repressed memory, whatever its validity, presents a classic problem for the law and science relationship.... [I]t remains woefully short of being empirically verified and, indeed, heralds from a non-rigorous school of psychology in which empirical validation is not a core tenet. The theory of repressed memories has its roots in clinical therapy, a domain in which validity is not a factor of overriding concern....

We believe the jury must decide what to do about the lack of empirical support. The Order would not even let the jury hear of the controversy and would, in effect, throw it and the case out of the courthouse, thus letting the judge decide the dispute if Frye were applied * * * . But what is gained by that? The need, as Professor Faigman describes it, is this:

Repression, in short, is a testable hypothesis, but it has not yet been appropriately tested. Pending satisfactory studies, therefore, the most reasonable scientific position is to maintain skepticism.

Martone dissent (quoting 1 FAIGMAN, ET AL. [Modern Scientific Evidence] § 13-2.4, at 150 (Supp.1999)).

We agree. The most reasonable position, scientific or unscientific, is to maintain skepticism about Plaintiff's claims. Justice Martone also suggests this case should be tested "under some heightened form of evidentiary scrutiny." Again we agree. But we have no doubt there will be very stringent scrutiny by the time able defense counsel finishes cross-examining Plaintiff and her witnesses, including Doctor van der Kolk. We are quite sure also that the nature of the case and the evidence produced by Defendant may well engender some skepticism in the minds of the jurors, just as it did with the trial judge. But as able as this trial judge is, and no matter how well founded his skepticism or ours, we believe the evidentiary testing should come from the adversary system and be decided by the jury. We make no constitutional pronouncement. We simply differ from the dissenters in this: having faith in the jury system, we believe jurors can handle the problem. Whether or not the jury finds Plaintiff's claims well founded, we are willing to indulge the presumption that the jurors will probably be right, or at least as right as the trial judge, and we, might be on this and the many other difficult issues of fact that come before our courts. More important, we believe the result we reach is in keeping with our system of justice and its preference for trial by jury on issues of fact.

Thus, we retain the Frye rule but continue to apply it as described in Hummert. * * * The trial judge's Minute Entry Order is vacated. The case may proceed in conformance with this opinion.

JONES, Vice Chief Justice, specially concurring:

I concur and join in the opinion and judgment of the majority but write separately because of \ the growing debate over the admissibility of expert testimony touching on fields of scientific endeavor * * * . * * *

The issue is uncomplicated. * * * [Dr.] van der Kolk[‘s] testimony is founded on specialized knowledge and is based on real experience. His qualifications are extensive.

It is my general observation that a range of factual scenarios and a variety of cause and effect circumstances in specialized scientific fields may remain unexplained for generations, as in aspects of cosmic science or in medical or other forms of life science. But it is also true, as a practical matter, that their actual occurrence, repeated time and again, may be well within an expert's specialized knowledge and experience. Notwithstanding the doubt that may encircle scientific theory, it is actual experience, whether in the laboratory, the clinic, or elsewhere, that has been the sine qua non of medical and scientific progress. And it seems to me such experience, under Rule 702, would assist the trier of fact to understand the issues and the evidence in the case at bar. The exclusion of uncertain or doubtful scientific theory is one thing, but the exclusion of specialized knowledge of actual trauma which stems from real experience is quite another.

I would admit the testimony of Dr. van der Kolk without reference [to] Frye v. United States, 293 F. 1013 (1923). It should be admitted to the extent it is based on actual experience, both as the factual basis on which to determine applicability of the statute of limitations and as the basis under Rule 702 to explain to the jury the nature of petitioner's claims. Van der Kolk is a trained medical expert with a breadth of experience dealing with substantial numbers of childhood sexual abuse victims. A ruling that would exclude van der Kolk purely on the basis that the trial judge may believe the "science" is uncertain would leave petitioner Logerquist and others like her with little but their individual testimony based on childhood memory, with no opportunity to introduce specialized evidence to explain things actually experienced at a tender age in their lives. This would impair substantial justice. [A]ny theory of repressed memory, valid or invalid, is easily distinguished from astrology because the former is invariably associated with severe mental or even physical trauma to the victim, whereas the latter involves no trauma and no victim. That is the whole point. Trauma caused by molestation is relevant * * * . * * *

Petitioner Logerquist alleges that her life has been severely impacted, that sexual assaults on her person were of such traumatic magnitude and incapacitated her emotional and mental self to such an extent that for many years she was unable to cope with or discuss her past or even face life's most essential decisions. In light of the complex medical implications and her young age at the time the alleged events occurred, she alone should not be expected to justify or even explain her symptoms. She claims depression. She was unable to remain employed and underwent years of mental therapy, allegedly necessitated by sexual abuse at the hands of the defendant. While the underlying scientific theories may remain uncertain, it is well known that child victims of sexual molestation by adults suffer profound forms of denial, anxiety, depression, and guilt. Their lives are often left in shock and degradation. Such conditions may endure for years, and experience-based testimony by a trained specialist would assist the jury to decide both the statute of limitations defense and the merits of petitioner's case.

To date, none of petitioner's allegations has been proved. They may never be proved to the satisfaction of a jury, and the statutory period of limitations may still bar her claim. Nevertheless, she should at least be accorded an opportunity to make her whole case. * * *

MARTONE, Justice, dissenting.

* * *

In Logerquist v. Danforth, 188 Ariz. 16, 23-24, 932 P.2d 281, 288-89 (App. 1996), the court of appeals remanded this case to the trial court for an evidentiary hearing on the validity of repressed memory under Frye. We denied review. The trial court then held a comprehensive evidentiary hearing and concluded that the relevant scientific community rejects the existence of repressed memory and the theory that such memories can be recalled with accuracy. Logerquist's offer of expert evidence thus failed to pass the general acceptance standard of Frye. The court of appeals declined to accept jurisdiction of Logerquist's petition for special action. * * *

If we were to continue to adhere to Frye, then we would affirm the ruling of the trial court. The hearing Judge McVey held under Frye was comprehensive and the majority does not take issue with his conclusion that repressed memory is simply not generally accepted in the scientific community. Expert testimony on repressed memory would thus be excluded. * * *

I.

How does the majority bypass Frye? It does so by stating that expert opinion testimony about repressed memory is not based upon scientific theory at all. According to the majority, because Frye only applies to scientific theories or processes, and repressed memory is unscientific, general acceptance is irrelevant and the evidence comes in. But this analysis is flawed. One would reach the exact opposite conclusion if one believed that repressed memory was not based on a scientific theory. If, as the majority asserts, repressed memory has no scientific basis, then, like astrology, expert testimony on it should be excluded. If, on the other hand, the theory of repressed memory is offered as having some scientific validity, then it must be subject to either Frye or Daubert scrutiny. Here, the theory is offered as having a basis in science. Logerquist's expert, Dr. van der Kolk, planned to testify that amnesia for traumatic events, including sexual abuse, "has been documented in numerous scientific reports" and that the notion is "well accepted in the relevant scientific community." Thus, Frye is fully applicable.

The majority reaches the quite remarkable conclusion that "Frye is inapplicable when a qualified witness offers relevant testimony or conclusions based on experience and observation about human behavior for the purpose of explaining that behavior." But observation-based experience and inductive reasoning lie at the heart of the scientific method. That expert evidence about human behavior has no basis in science will be astounding news to the medical community. It also means that any psychiatrist, psychologist, or "human behavioralist" can be called as an "expert" and render any theory of human behavior, however farfetched. This presents a profound danger to our judicial system. Neurobehavioral genetics is an emerging field. The ways in which genes affect the brain and human behavior raise all sorts of issues: the relationship between genes and criminal violence; the relationship between genes and mental disorders; the relationship between genes and behavioral disorders; the relationship between genes and addictive disorders; and the list goes on. See Dean Hamer and Peter Copeland, Living With Our Genes (1998).

After today's decision, any "expert" can walk into an Arizona courtroom and testify about human behavior without any threshold showing of scientific reliability. Yet, with a renegade exception, courts that have addressed the admissibility of expert testimony on repressed memory have applied either Frye or * * * some [other] form of heightened evidentiary scrutiny.

The majority neglects these cases and, instead, is drawn to Wilson v. Phillips, 73 Cal. App. 4th 250, 86 Cal. Rptr. 2d 204 (1999), a sui generis opinion of California's intermediate appellate court. The distinction in Wilson (distinguishing expert medical opinion from scientific theories) is contrary to Arizona law and common sense. Expert medical opinions must be based on medical science as it is currently known. A contrary conclusion would reduce medicine to magic.

The majority's reliance upon State v. Hummert, 188 Ariz. 119, 933 P.2d 1187 (1997), to support its conclusion that Frye does not apply here is misplaced. In Hummert, we distinguished between two kinds of evidence. One involved the scientific validity of DNA identification techniques. As to this, we said Frye applied. We also said it was generally accepted under Frye. The other evidence was expert experience with DNA matches. We allowed opinion evidence concerning the expert's experience with random matches without subjecting that experience to a Frye analysis, because the scientific principles that were at the basis of their personal experience had already been subjected to a successful Frye analysis. Thus, under Hummert, the theory of repressed memory would first have to satisfy Frye. If it did, then and only then could an expert offer an opinion based on experience.

So too, in State v. Lindsey, 149 Ariz. 472, 473, 720 P.2d 73, 74 (1986), we permitted expert testimony that explained "recognized principles of social or behavioral science which the jury [could] apply to determine issues in the case." The principles were already recognized. Here, of course, we have a very different case. Repressed memory has not been generally recognized. It is a new and controversial theory which attempts to explain the brain's response to trauma under the banner of science. Thus, we should not allow expert testimony based upon personal experience in this area unless and until it satisfies Frye.

Nor does State v. Roscoe, 145 Ariz. 212, 700 P.2d 1312 (1984) (Roscoe I) advance the majority's position. We had to acknowledge error in admitting the dog scent evidence when it turned out that the expert was a "charlatan" and his theory "fabricated." State v. Roscoe, 184 Ariz. 484, 489 n. 1, 910 P.2d 635, 640 n. 1 (1996) (Roscoe II ). We thus erred in Roscoe I in allowing the use of this evidence without any preliminary showing of reliability. It is precisely because of cases like Roscoe I that the trial court's role as a gatekeeper is so important. The majority's revised reading of Hummert, Lindsey, and Roscoe I casts Frye right out of our jurisprudence.

Having shown that Frye does apply, here is how we should deal with it. A preeminent treatise on scientific evidence says this about the relationship between repressed memory and the law:

In many respects, the phenomenon of repressed memory, whatever its validity, presents a classic problem for the law and science relationship....[I]t remains woefully short of being empirically verified and, indeed, heralds from a non-rigorous school of psychology in which empirical validation is not a core tenet. The theory of repressed memories has its roots in clinical therapy, a domain in which validity is not a factor of overriding concern. In therapy, support and improved mental health are the predominant outcome measures.

1 David L. Faigman, David H. Kaye, Michael J. Saks & Joseph Sanders, Modern Scientific Evidence: The Law and Science of Expert Testimony § 13-1.5, at 534-35 (1997).

There may be no area of contemporary psychiatry and psychology more controversial than the theory of repressed memory. "Questions are raised about the authenticity of such reported memories, people's ability to recall such memories, the techniques used to recover these memories, and the role of therapists in developing the memories." Id. § 13-2.3, at 539. Indeed, the preeminent professor of law and psychiatry at Harvard University notes well the problem of memory, "infantile amnesia" and its effect on the legitimacy of Freudianism itself.

The task of constructing self-descriptions in psychoanalytic therapy also encounters the problem of memory. Everything we have learned in recent years about memory has emphasized its plasticity, the ease with which it can be distorted, and the difficulties of reaching a hypothetical veridical memory. Much of what psychoanalysis considered infantile amnesia may be a function of the reorganizing brain rather than of the repressing mind. All of this makes the task of constructing meaningful histories of desire in the individual more daunting.

If there is no important connection between childhood events and adult psychopathology, then Freudian theories lose much of their explanatory power. If memory cannot be trusted to construct a self-description, what does one do in therapy?

Alan A. Stone, M.D., Where Will Psychoanalysis Survive: What Remains of Freudianism When Its Scientific Center Crumbles?, Harv. Mag., Jan.-Feb.1997, at 39.

This debate lies at the essence of Frye. Repressed memory does not lie within the range of common knowledge. Experts in psychology and psychiatry cannot reach agreement about its validity. See Modern Scientific Evidence § 13-2.0, at 115-50 (Supp.1999). And, if experts cannot agree about the validity of repressed memory, how do we pass this question to the jury without first reviewing its reliability under some heightened form of evidentiary scrutiny? That is what Frye is all about. Here is what some experts conclude:

Repression, in short, is a testable hypothesis, but it has not yet been appropriately tested. Pending satisfactory studies, therefore, the most reasonable scientific position is to maintain skepticism.

Id. at 150. The trial court properly excluded this theory under Frye. * * *

III.

If Frye is still the law of Arizona, then the trial court's findings in this case are unassailable. The theory of repressed memory has not found general acceptance in the scientific community. Thus, it was proper for Judge McVey to exclude expert opinion testimony on this subject. The majority's claim to adhere to Frye and yet avoid this result is unfathomable. . . .

McGREGOR, Justice, dissenting:

* * *

I also question whether the distinction the majority makes between "scientific" evidence, which must meet the Frye test to be admissible, and "non-scientific" evidence, which need not comply with Frye, rests on a firm basis. According to the majority, evidence is "scientific" if an expert witness reaches his or her conclusion through the use of deductive reasoning, and not scientific if the expert relies upon inductive reasoning. I do not believe that distinction will prove useful and suspect it will produce inexplicable evidentiary rulings. For example, research scientists tell us that certain components of human behavior seem to be related to, and may be caused by, genetic characteristics. In an action similar to that before us, if one expert, relying upon his observations, reaches a conclusion about a party's "human behavior" by reasoning inductively, his testimony would be admissible so long as his credentials are acceptable. But if another expert witness, with an equally impressive curriculum vitae, concludes that the plaintiff's human behavior could be explained by reasoning deductively from known principles of genetics, that expert's testimony would be subject to the Frye analysis. The admissibility of testimony from two expert witnesses about the same subject-a litigant's human behavior-would be tested against two different standards. And, as noted above, whether each expert can testify will depend in large part upon whether the action proceeds in state or in federal court. I see no benefit to trial courts or litigants from following a path that leads to such a result.

Moreover, unlike the majority, I would not permit the admission of unreliable evidence in the hope that the adversary process will disclose its lack of validity. I do not think that allowing a jury to hear unreliable, invalid "expert" evidence benefits either our judicial system or the litigants. . . . . We can justify admitting unreliable, invalid evidence only if we are willing to substitute a trial judge's analysis of an expert witness's credentials for the judge's analysis of the reliability of the data and methods used to produce the expert's testimony.