United States v. Larry D. Hall

*1118 EASTERBROOK, Circuit Judge,

concurring.

At Hall’s first trial, the district court excluded expert testimony that Hall is especially vulnerable to suggestive interrogation. The judge thought that jurors have experience with questioning and can figure this subject out for themselves, but we observed: “Because the fields of psychology and psychiatry deal with human behavior and mental disorders, it may be more difficult at times to distinguish between testimony that reflects genuine expertise — a reliable body of genuine specialized knowledge — and something that is nothing more than fancy phrases for common sense. It is nevertheless true that disorders exist, and the very fact that a layperson will not always be aware of the disorder, its symptoms, or its consequences, means that expert testimony may be particularly important when the facts suggest a person is suffering from a psychological disorder. ... The court indicated that it saw no potential usefulness in the evidence, because it was within the jury’s knowledge. This ruling overlooked the utility of valid social science. Even though the jury may have had beliefs about the subject, the question is whether those beliefs were correct. Properly conducted social science research often shows that commonly held beliefs are in error.” 93 F.3d 1337, 1343, 1345 (7th Cir.1996). On remand, the district court inquired whether the testimony would be scientifically valid and reliable, see Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 , 113 S.Ct. 2786 , 125 L.Ed.2d 469 (1993), answered “yes,” and admitted the evidence. 974 F.Supp. 1198 (C.D.Ill.1997). But the district court excluded expert testimony about eyewitness identification, observing that jurors have experience with observation and memory and can figure this subject out for themselves. Hall contends that the court has committed the same error a second time.

The district judge relied on United States v. Daniels, 64 F.3d 311 (7th Cir.1995), and its predecessors. Daniels states that “[ejxpert testimony regarding the potential hazards of eyewitness identifications ... will not aid the jury because it addresses an issue of which the jury already generally is aware, and it will not contribute to their understanding of the particular factual issues posed.” 64 F.3d at 315 . United States v. Hudson, 884 F.2d 1016, 1024 (7th Cir.1989), and United States v. Larkin, 978 F.2d 964, 971 (7th Cir.1992), say the same thing. These decisions do not address the point the prior panel in this case made: “Properly conducted social science research often shows that commonly held beliefs are in error.” Jurors who think they understand how memory works may be mistaken, and if these mistakes influence their evaluation of testimony then they may convict innocent persons. A' court should not dismiss scientific knowledge about everyday subjects. Science investigates the mundane as well as the exotic. That a subject is within daily experience does not mean that jurors know it correctly. A major conclusion of the social sciences is that many beliefs based on personal experience are mistaken. The lessons of social science thus may be especially valuable when jurors are sure that they understand something, for these beliefs may be hard for lawyers to overcome with mere argument and assertion.

Another line of cases in this circuit, which Hudson, Larkin, and Daniels do not cite or discuss, is more open to the possibility that expert testimony may be especially valuable when the subject is “common knowledge.” In Carroll v. Otis Elevator Co., 896 F.2d 210 (7th Cir.1990), for example, the court held it proper to admit the testimony of a psychologist about how colors influence children’s behavior. A concurring opinion in Carroll elaborated: “In principle, a product could be unreasonably dangerous because its designers neglected to consider how children see things. A specialist in vision, illusion, and reaction is just the sort of person to assist on such questions. The manufacturer observes that expert testimony is inappropriate when the subject lies within the ken of laymen and insists that ‘everyone knows’ red is attractive. Maybe, but much of the science of experimental psychology consists in demonstrating that what ‘everybody knows’ is false.” 896 F.2d at 215 . Our opinion in Krist v. Eli Lilly & Co., 897 F.2d 293 (1990), is in the same vein. “An important body of psychological research undermines the lay intuition that confident memories of salient *1119 experiences ... are accurate and do not fade with time unless a person’s memory has some pathological impairment.... The basic problem about testimony from memory is that most of our recollections are not verifiable. The only warrant for them is our certitude, and certitude is not a reliable test of certainty. Many people are certain that God exists. Many are certain that He does not exist. The believer and the nonbeliever are equally certain, but they cannot both be correct. Similarly, the mere fact that we remember something with great confidence is not a powerful warrant for thinking it true. It therefore becomes an empirical question whether and in what circumstances memory is accurate.” 897 F.2d at 296-97 (citations to the scholarly literature omitted). See Elizabeth F. Loftus & James M. Doyle, Eyewitness Testimony: Civil and Criminal (3d ed.1997). Krist suggested that a litigant could present expert testimony about “the vagaries of memory”, 897 F.2d at 298 , and remarked on the tension between Hudson and Carroll . Courts elsewhere are divided, though recent opinions have been more hospitable than Hudson and Daniels to the posr sibility of expert testimony about perception, memory, and identification. E.g., United States v. Brien, 59 F.3d 274, 277 (1st Cir.1995) (collecting cases); United States v. Stevens, 935 F.2d 1380 (3d Cir.1991).

My colleagues finesse the subject by concluding that a district judge has discretion to assess the utility of evidence under Rules 403 and 702, and to admit or exclude it as circumstances require. This is, in the end, all that Daniels, Larkin, and Hudson hold: that the district judges in those cases had not abused their discretion, General Electric Co. v. Joiner, 522 U.S. 136 , 118 S.Ct. 512 , 139 L.Ed.2d 508 (1997), by excluding particular evidence. See Krist, 897 F.2d at 298 . I agree with this conclusion and join the opinion. But I am inclined to think that Daniels is right to suggest that evidence of this kind should not be admitted — though not for the reason Daniels gives.

Much of the adversarial system rests on empirical propositions that may be investigated, and sometimes refuted, through scientific means. Consider, for example, the proposition — fundamental to any system that relies on lay adjudicators — that jurors understand and follow the instructions given by the court. It may be that jurors don’t understand legalese, or if they understand the instructions don’t follow them. See Free v. Peters, 12 F.3d 700 (7th Cir.1993); Gacy v. Welborn, 994 F.2d 305 (7th Cir.1993); Neil Vidmar, The Performance of the American Civil Jury: An Empirical Perspective, 40 Ariz. L. Rev. 849 (1998) (recapitulating evidence about this issue). Or consider cross-examination. Jurors may believe that witnesses who hesitate, perspire, or fidget during cross-examination are hiding the truth. This is the view that underlies polygraph examinations, but without the precision of measurement. Is it true? Calm and collected liars deceive polygraph examiners (and thus jurors too); other witnesses grow restless or testy although they have nothing to hide. Suppose one of the litigants offers an expert in physiology to explain to jurors the (weak) correlation between lying and the appearance of discomfort on the stand. Or an expert in group dynamics to explain to a potential dissenter on the jury how to resist the pressure of the majority to go along — or for that matter how to see through lawyers’ rhetorical tricks. Because trials rest on so many contestable empirical propositions, including those about eyewitness recollection, it always would be possible to offer expert evidence along these and related lines.

Yet a trial about the process of trials not only would divert attention from the main question (did Hall kill Jessica Roach?) and substantially lengthen the process but also would not do much to improve the accuracy of the outcome. Social science evidence is difficult to absorb; the idea of hypothesis formulation and testing is alien to most persons. That’s one reason why the training of social scientists is so extended. Delivering a graduate level statistical-methods course to jurors is impractical, yet without it a barrage of expert testimony may leave the jurors more befuddled than enlightened. Many lawyers think that experts neutralize each other, leaving the jurors where they were before the process began. Many lawyers think that the best (= most persuasive) experts are those who have taken acting lessons and have deep voices, rather than those who have done the best research. Perhaps *1120 that is too pessimistic a view; but then the effect of experts is itself a question open to empirical inquiry, which might be added to the agenda for trial.

Instead of using the trial process to assess trials at retail, judges can and should employ social science to improve the trial process. Lessons about how jurors respond to jury instructions can be used to draft better instructions. (The Federal Judicial Center’s pattern instructions were drafted with the aid of social scientists; so were this circuit’s pattern criminal instructions.) Recognition that jurors cannot (and do not) always heed judges’ instructions to disregard what they have heard, or to consider evidence against one litigant but not another, leads courts to prevent the use of certain kinds of evidence or to sever the proceedings. E.g., Gray v. Maryland, 523 U.S. 185 , 118 S.Ct. 1151 , 140 L.Ed.2d 294 (1998). Linguists and other experts could help jurors to interpret statutes, but judges do that task instead and give the results to the jury. Similarly a judge, recognizing the main conclusions of the scholarly study of memory — that “accuracy of recollection decreases at a geometric rather than arithmetic rate (so passage of time has a highly distorting effect on recollection); accuracy of recollection is not highly correlated with the recollector’s confidence; and memory is highly suggestible — people are easily ‘reminded’ of events that never happened, and having been ‘reminded’ may thereafter hold the false recollection as tenaciously as they would a true one”, Krist, 897 F.2d at 297 (emphasis in original) — could block a lawyer from arguing that a given witness is sure of his recollection, and therefore is more likely to be right. The judge could inform jurors of the rapid decrease of accurate recollection, and the problem of suggestibility, without encountering the delay and pitfalls of expert testimony. Jurors are more likely to accept that information coming from a judge than from a scholar, whose skills do not lie in the ability to persuade lay jurors (and whose fidgeting on the stand, an unusual place for a genuine scholar, is apt to be misunderstood). Altogether it is much better for judges to incorporate scientific knowledge about the trial process into that process, rather than to make the subject a debatable issue in every case. There remains a question about where judges acquire scientific knowledge, for they too may be mistaken in what they think they know. Still, professional adjudicators who attend continuing judicial education programs and read the scholarly literature are more likely to absorb the lessons of science than are jurors force fed a little information during a trial.

Hall did not ask the judge to pass scientific knowledge on to the jury. His lawyers did not appreciate the big difference between the expert evidence considered on the first appeal and the evidence offered on remand. The evidence we dealt with the last time around was evidence about Hall, suggesting that his psychological makeup was abnormal, not evidence about how ordinary witnesses interact with the trial process itself. Or, to put this in the language of administrative law, the expert testimony in the first trial was about an adjudicative fact; the proposed expert testimony in the second trial would have concerned a legislative fact. Hall did not object to any line of questioning or argument as incompatible with the lessons of science. So the possibilities I have been exploring are not presented in this case. But the subject is vital to a judicial system that seeks to improve the accuracy of the trial process, and thus as time passes more of the findings of modern social science research should be incorporated into legal rules about proper trial tactics and arguments.