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. e du/thir dc ir c uit_2001/200Filed August 30, 2001

UNITED STATES COURT OF APPEALS

FOR THE THIRD CIRCUIT

No. 99-5940

UNITED STATES OF AMERICA Appellee

v.

KEITH MATHIS Appellant

On Appeal from the United States District Court for the District of New Jersey

NO. 98-cr-656-2 District Judge: Honorable Alfred J. Lechner, Jr.

Argued June 1, 2000

Before: SCIRICA and NYGAARD, Circuit Judges and POLLAK,* District Judge

(Filed: August 30, 2001)

___________________________________________________ ______________ * Honorable Louis H. Pollak, United States District Judge for the Eastern District of Pennsylvania, sitting by design ation.Robert J. Cleary, Esq.

George S. Leone, Esq. Phillip H. Kwon, Esq. (argued) United States Attorney Assistant United States Attorney

970 Broad Street

Room 700 Newark, NJ 07102

Counsel for Appellee United States

of America

Mark A. Berman, Esq. (argued) Peter J. Torcicollo, Esq. Gibbons, Del Deo, Dolan, Griffinger & Vecchione

One Riverfront Plaza Newark, NJ 07102

Counsel for Appellant

OPINION OF THE COURT

POLLAK, District Judge:

This appeal concerns three challenges to Keith Math is's conviction for bank robbery and conspiracy to commi t bank robbery. First, Mr. Mathis claims that the District Court wrongly admitted into evidence testimony describing his involvement in previous, uncharged bank robberies. Second, Mr. Mathis asserts that the District Court erred in admitting evidence that his picture was selected fr om a photographic array, because the array was unconstitutionally suggestive. Third, Mr. Mathis ar gues that the District Court wrongly excluded expert tes timony that called into question eyewitness testimony iden tifying Mr. Mathis as he fled from the robbery. As describe d herein, we disagree with Mr. Mathis's first and sec ond arguments on their merits; with respect to the thir d, we hold that the District Court erred in part, but we find it highly improbable that such error affected the jury 's decision. Thus, we affirm Mr. Mathis's conviction.

2I. Background

On October 20, 1998, a grand jury indicted Mr. Math is, Steven Gantt, and Jeffrey Seaberry on one count of bank robbery, in violation of 18 U.S.C. SS 2113(a) and 2 , and one count of conspiracy to commit bank robbery, in viol ation of 18 U.S.C. S 371. The indictment charged the three m en with conspiring, from October 11 to October 14, 199 8, to rob the Sun National Bank in Maple Shade, New Jerse y, and with successfully robbing that bank on October 14, 1998. Mr. Mathis pled not guilty to both counts, an d his trial commenced on January 19, 1999.

At Mr. Mathis's trial, two witnesses testified that they saw, from an adjoining office building, three maske d men with guns run into, and then out of, Sun National B ank.

These witnesses testified that the three masked men drove away in a dark-colored Jeep. Also, several Sun Nati onal Bank employees testified that, when the three were inside the bank, one stood near the door holding two guns, while the other two jumped over the bank counter and took money from tellers' drawers. Video footage taken by the bank's security cameras confirmed the basic details of

these accounts.

The prosecution's primary witnesses were Sergeant G ary Gubbei and one of Mr. Mathis's alleged co-conspirat ors, Mr. Gantt. Sergeant Gubbei testified that, on the morni ng of October 14, he responded to a radio dispatch descri bing the robbery and the getaway vehicle. Soon thereafter, S ergeant Gubbei spotted a black Jeep Cherokee with an Africa nAmerican driver in the opposing lane of traffic; Se rgeant Gubbei turned and gave chase. After a period of pur suit, the Jeep left the highway and drove onto a grass me dian, where the vehicle apparently stalled and coasted to a halt. Three men exited the Jeep while it was still moving --the driver first, then a forward passenger, then a rear passenger--and escaped over a guardrail on the high way's far side. The forward passenger, while stumbling ov er the guardrail, dropped a black bag containing money. Th e rear passenger carried a gun in his right hand as he exi ted the Jeep and held the weapon near his head, pointing to ward the sky. The rear passenger momentarily looked back at Sergeant Gubbei before running away, and Sergeant

3Gubbei testified at trial that he was able, based o n that

brief view, to identify the fleeing man as Mr. Math is. Sergeant Gubbei also testified that, at 1:00 p.m. o n October 15, he selected Mr. Mathis's picture from an eight- picture photographic array as depicting one of the Jeep's

occupants.

Mr. Gantt, who pled guilty in this case, testified that he and Mr. Mathis jointly robbed a total of twelve ban ks, including the Sun National Bank, and that seven of these robberies, including that of the Sun National Bank, also involved Mr. Seaberry. Mr. Gantt further testified that these

seven robberies shared other characteristics: The r obbers covered their faces with masks; the robbed banks we re located near Camden, New Jersey; and Mr. Mathis oft en stood as an armed guard, while Mr. Gantt and Mr. Se aberry

vaulted the counters and stole cash from the drawer s.

In describing the Sun National Bank robbery, Mr. Ga ntt testified that Mr. Mathis, Mr. Seaberry, and he par ked a Jeep at the rear of the bank's parking lot, donned face masks, ran alongside the bank, and entered through the front of the building. Mr. Gantt stated that he and Mr. Seaberry jumped over the tellers' counters and plac ed money from the drawers in a bag they were carrying, while Mr. Mathis stood guard with two pistols. The three then returned to the Jeep. Mr. Seaberry drove, Mr. Gantt rode in the forward passenger's seat, and Mr. Mathis rode i n the rear passenger's seat. Mr. Gantt testified that, as the Jeep tried to evade a pursuing police cruiser (apparentl y driven by Sergeant Gubbei), Mr. Seaberry tried to drive ov er the highway's grass divider, causing the Jeep's engine to stall,

and the three men exited while the vehicle was stil l rolling forward. Mr. Gantt stated that he and Mr. Mathis ju mped over the highway guardrail and, without Mr. Seaberr y, escaped after stealing a nearby delivery truck. At trial,

Detective Jeff Hoch testified that he arrested Mr. Seaberry near an apartment complex beside the highway.

II. Grounds for Appeal

A. Evidence of Uncharged Robberies

At trial, the government moved in limine to admit i nto evidence testimony from Mr. Gantt concerning eleven

4robberies that he and Mr. Mathis had jointly undert aken

prior to the Sun National Bank robbery. The governm ent first addressed the testimony's admissibility under Federal Rule of Evidence 404(b), which states:

Evidence of other crimes, wrongs, or acts is not admissible to prove the character of a perso n in order to show action in conformity therewith. It m ay, however, be admissible for other purposes, s uch as proof of motive, opportunity, intent, prepar ation, plan, knowledge, identity, or absence of mistake o r accident

. . . .

Fed. R. Evid. 404(b). According to the government, the disputed evidence was admissible, inter alia, to sh ow Mr. Mathis's familiarity with Mr. Gantt and Mr. Seaberr y prior to the charged offense and to show the group's modu s operandi for robbing banks. In response, Mr. Mathis conceded that Rule 404(b) was satisfied, but he cla imed that Mr. Gantt's testimony presented a risk of unfa ir prejudice that substantially outweighed its probati ve value and was therefore barred by Rule 403, which provide s:

Although relevant, evidence may be excluded if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury, or by considerations of undue delay, waste of time, or needless presentati on of

cumulative evidence.

Fed. R. Evid. 403.

The District Court admitted Mr. Gantt's testimony i nto evidence, holding, as a preliminary matter, that Ru le 404(b) was satisfied because the testimony's description o f uncharged acts was linked to charged conduct by"[t] he same general area, the same general time period, th e intent entering into the conspiracy, the background of thi s, the familiarity [of] one with the other, the agreement among everyone and the knowledge with regard to how to ca rry out bank robberies." With respect to Rule 403, the Dist rict Court acknowledged that there was "prejudice in thi s evidence," but it also found that the evidence"poss ess[ed] great probative value." Mr. Mathis's defense was on e of mistaken identity, and the District Court found tha t"[t]his

5evidence from a co-defendant links him directly to the

crime, directly with the evidence of the police off icer who will testify. . . . I find it is not unfairly preju dicial looking at what the Government must prove, what is available t o the Government and who is going to be offering the test imony." When Mr. Gantt completed his testimony regarding th e uncharged robberies, the District Court read a jury instruction (whose substance is not challenged) lim iting use of the testimony to showing "defendant's knowledge of the crime of bank robbery and . . . his familiarity wit h the other alleged co-conspirators" and to showing "that the r obbery of Sun National Bank was part of a scheme or plan in w hich the defendant participated." The District Court st ressed that the jury could consider such evidence "only fo r [those] limited purposes . . . [and] to use the evidence fo r any other purpose would be improper and violative of your oat h."

We review a district court's decision to admit or e xclude evidence for abuse of discretion, and such discreti on is construed especially broadly in the context of Rule 403. E.g., Hurley v. Atl. Police Dep't, 174 F.3d 95, 110 (3d Cir. 1999). On appeal, Mr. Mathis claims that Rule 403 s hould have barred the contested portion of Mr. Gantt's te stimony because "evidence relating to so many other uncharg ed bank robberies" inevitably prejudiced the jury"by demonstrating that Mathis had a propensity to rob b anks." Appellant's Br. at 28. He also claims that such tes timony was not significantly probative because the governm ent "could establish Mathis' identity, or his associati on to Gantt . . . by Sergeant Gubbei's eyewitness identificatio n. . . and [by] Steven Gantt's testimony that he was acquainte d with

Mathis and that he . . . robbed the Sun National Ba nk with

the defendant." Id. at 30.

With respect to the testimony's risk of prejudice, we agree with the District Court that the disputed testimony 's description of eleven uncharged robberies, in a cas e seeking conviction on only one, entailed some risk of unfai r prejudice. That is, the jury could well have interp reted Mr. Gantt's testimony as proving that Mr. Mathis was a person of bad character who deserved punishment independen t of the government's particular proof regarding the Sun National Bank robbery. But in United States v. O'Le ary, 739

6F.2d 135 (3d Cir. 1984), this court held that the n umber of

uncharged acts alleged, even if disproportionate to the number of charged acts, does not alone render admis sion of

such evidence an abuse of discretion. The defendant in O'Leary was charged with one count of conspiracy to distribute cocaine and five counts of possession wi th intent to distribute cocaine. Mr. O'Leary claimed that the district court erroneously admitted testimony stating that h e had sold drugs on "[a]bout 20" occasions during the cou rse of "[a]bout a year." Id. at 136. We affirmed the convi ction, finding that the district court had expressly analy zed the defendant's Rule 403 challenge and had issued an instruction "clearly explaining to the jury the nar row way in which to use the evidence," thereby "lessen[ing] an y possibility of prejudice." Id. Similarly, in the ca se at bar, the District Court explicitly balanced the testimony's probative value against its danger of unfair prejudice, and i t instructed the jury on the permissible uses of Mr. Gantt's testimony.1

The chief authority on which Mr. Mathis relies is U nited States v. Hans, 738 F.2d 88 (3d Cir. 1984), where w e reversed a defendant's conviction for bank robbery and assault during the commission of a bank robbery. Th e testimony in Hans was from an FBI agent, and it des cribed the surprising speed with which the defendant becam e a suspect in the case. Such testimony was deemed extr emely prejudicial because, in context, "the only reasonab le inference that a reasonable juror could draw from t he testimony was that Hans was well-known as a bank ro bber

___________________________________________________ ______________

1. Mr. Mathis seeks to distinguish O'Leary because the witness in that case answered relatively few, relatively cursory qu estions about the defendant's previous misconduct, while "the governm ent's examination of Gantt regarding the details of the eleven uncharged bank robberies went on for 34 pages, and dominated Gantt's trial testim ony." Reply Br. at 26. We cannot agree that the government's efficiency, o r lack thereof, in conducting Mr. Gantt's examination significantly de termines the resultant testimony's prejudicial effect. Here, as in O'Leary, the government's questions were sufficient in duration and substance to raise the defendant's prior misconduct as an issue, and this fact alone--not any claim of "undue delay, waste of time , or needless presentation of cumulative evidence"--is the defend ant's asserted basis for prejudice.

7to the Detroit F.B.I." Id. at 94; id. ("[I]t is di fficult to imagine

testimony more prejudicial than [the] implication t hat Hans was known to the Detroit police as a professional b ank robber . . . ."). Mr. Mathis has presented no argum ent that Mr. Gantt's testimony implicated the unusual risk o f prejudice discussed in Hans, and we see no reason t o believe it did so. Whereas the testimony in Hans ge nerated

untestable inferences about what was "well-known" b y the "Detroit F.B.I.," Mr. Gantt testified directly rega rding his own experience. Thus, Mr. Gantt's testimony was pro perly challengeable, and was in fact challenged, by vigor ous cross-examination, which significantly mitigated it s risk of unfair prejudice. Cf. United States v. Gonzalez-Lir a, 936 F.2d 184, 191 (5th Cir. 1991) (finding the prejudic ial effect caused by evidence of past acts mitigated by the opportunity to cross-examine and by a proper limiti ng instruction); United States v. Lynn, 856 F.2d 430, 437 (1st Cir. 1988) (finding the risk of prejudice "especial ly distressing" where the defendant "could not . . . c rossexamine the agent on the reliability of the informa tion").

With respect to the other part of Rule 403's analys is, the District Court found that Mr. Gantt's testimony pos sessed "great probative value." On appeal, the government argues that the disputed testimony "was admissible to show the familiarity and interrelationship of Mathis, Gantt, and Seaberry," thereby tending to prove Mr. Mathis's co nspiracy count. Appellee's Br. at 53-55. In evaluating this position, we take guidance from this court's holding in Unite d States v. Scarfo, 850 F.2d 1015 (3d Cir. 1988). The defend ant in Scarfo was convicted of conspiring to extort, and o f extorting, money from a real estate developer. The district court admitted testimony from two of the defendant' s coconspirators stating that, prior to the charged ext ortion, they had committed two murders pursuant to the defendant's orders. These co-conspirators also test ified

about numerous details of the defendant's "crime fa mily," including uncharged murders, briberies, and extorti ons. On appeal, we affirmed the defendant's conviction, hol ding that "[b]ecause the government's case against the defend ants rested on the testimony of unindicted co-conspirato rs, evidence describing their relationship to the defen dants and providing background information to illustrate the

8witnesses' roles in the scheme was properly admitte d." Id.

at 1020. Also, in order for the jury "to realize th at [the coconspirators] had been granted immunity for the ver y murders that they asserted Scarfo had ordered" and thereby to assess the witnesses' motive for testify ing, we

concluded that such evidence was "essential in the government's effort to establish the credibility of its disreputable, yet indispensable witness." Id.

The charged conduct here, of course, lacks much of the gravity and extensiveness associated with the activ ities described in Scarfo, but the applicable legal princ iples are

not so dissimilar. Mr. Mathis was indicted for a co nspiracy, whose details the government was required to prove, and Mr. Gantt was the government's only witness who cou ld describe the conspiracy directly. Mr. Gantt's testi mony regarding the eleven uncharged robberies, if believ ed by the jury, explained both Mr. Gantt's role in the conspi racy and his motive for testifying, i.e., to fulfill his ple a agreement and reduce his sentence. This testimony also tended to show that, in addition to their previous associatio ns, Mr. Gantt and Mr. Mathis conspired in robbing Sun Natio nal Bank, on the theory that co-conspirators more often trust those with whom they are already intimate. Contrary to Mr. Mathis's argument that the disputed testimony was unnecessary given other evidence in the case, Mr. G antt's testimony was the only direct evidence offered for the purposes listed above. Accordingly, for reasons par allel to those in Scarfo, we deem Mr. Gantt's testimony sign ificantly probative of Mr. Mathis's involvement in the charge d conspiracy.2

___________________________________________________ ______________

2. The government also argues that Mr. Gantt's test imony demonstrates a common modus operandi. The government's position begins with the solid premise that "[a] jury can rationally infer f rom evidence that the defendant committed a prior crime in an unusual and distinctive manner

and evidence that a second similar crime was commit ted in the same

unusual and distinctive manner that the defendant c ommitted the second crime." Gov't of Virgin Islands v. Pinney, 9 67 F.2d 912, 916 (3d Cir. 1992). In order to distinguish this type of in ference from impermissible conclusions based on propensity or ba d character, however, the admissibility of such evidence critica lly depends on the degree to which the "manner" employed is "unusual a nd distinctive." 1

9After reviewing the District Court's explanation fo r its

ruling, we find no abuse of discretion in the Distr ict Court's conclusion that the disputed testimony's danger of unfair prejudice did not substantially outweigh its probat ive value. Mr. Gantt's testimony about the uncharged robberies provided significant background information bolster ing the charged conspiracy's plausibility, and the risk of prejudice attending such evidence was mitigated by the opport unity for cross-examination and by the District Court's l imiting instruction. Thus, we hold that the District Court did not abuse its discretion by declining to exclude Mr. Ga ntt's testimony.

B. Evidence of Photographic Identification

Before trial, the District Court conducted an evide ntiary hearing to determine the admissibility of testimony from Sergeant Gubbei stating that he saw Mr. Mathis exit the Jeep on October 14, 1998, and that he selected Mr. Mathis's picture from a photographic array on Octob er 15, 1998. At that hearing, Sergeant Gubbei testified th at he chose Mr. Mathis's photograph from an array of eigh t photographs at the Maple Shade police department, a nd Mr. Mathis moved to exclude such testimony because Sergeant Gubbei had previously seen an identical

___________________________________________________ ______________

McCormick on Evidence 662-63 (John W. Strong ed., 5 th ed. 1999) ("Much more is demanded than the mere repeated comm ission of crimes of the same class, such as repeated murders, robber ies, or rapes. The pattern and characteristics must be so unusual and distinctive as to be like a signature.") (footnotes omitted). On this po int, Mr. Gantt's testimony indicated only that all of the uncharged robberies at issue occurred near Camden, New Jersey, within approximat ely four months of one another, and that the robbers wore gloves and m asks. Mr. Gantt further testified that sometimes his girlfriend wai ted outside the target bank in a car, other times she did not; sometimes o ne robber acted as an armed guard near the bank's door, sometimes not; sometimes the robbers would use a stolen getaway car, other times not; sometimes they used a .45 caliber handgun, other times a .22 calib er handgun, and sometimes they used toy guns or screwdrivers taped to look like guns. None of the authorities cited by the government has approved modus operandi admissibility based on such inconsistent a nd generally nondistinctive characteristics, and we find the eviden ce in this case insufficient to support such a theory.

10photograph of Mr. Mathis. Specifically, a Maple Sha de

detective had, roughly one month before the robbery , given Sergeant Gubbei materials describing various bank r obbery suspects. According to Sergeant Gubbei, these mater ials included between thirteen and fifteen pages with approximately seven photographs of bank robbery sus pects, and one of these photographs--virtually identical t o that later placed in the array--depicted Mr. Mathis. 3

Mr. Mathis argued that admitting this testimony fro m Sergeant Gubbei would violate the Due Process Claus e's protection against certain suggestive identificatio n procedures. In particular, Neil v. Biggers, 409 U.S . 188 (1972), held that, for out-of-court identifications

, "convictions based on eye-witness identification . . . will be set aside only if the photographic identification w as so impermissibly suggestive as to give rise to a very

substantial likelihood of . . . misidentification." Id. at 196- 97 (internal quotation omitted).4 Biggers further declared

that likelihood of misidentification should be meas ured by a totality of circumstances including: the witness' s initial opportunity to view the suspect at the crime scene and degree of attention at that time, the witness's lev el of certainty in the disputed identification, the lengt h of time between initial viewing and disputed identification , and the accuracy of any intervening description of the susp ect occurring between those two events. Id. at 199-200.

In the present case, Mr. Mathis contended that "the very fact of [a] previous viewing" was itself sufficient to establish the identification procedure's suggestiveness. He f urther argued that a substantial likelihood of misidentifi cation arose both from Sergeant Gubbei's limited opportuni ty to view Mr. Mathis as he fled and from Sergeant Gubbei 's

___________________________________________________ ______________

3. We base much of our analysis on Sergeant Gubbei' s testimony because the materials themselves, aside from the pa ge containing Mr. Mathis's picture, apparently were not introduced in to evidence.

4. See also United States v. Emanuele, 51 F.3d 1123 , 1128 (3d Cir. 1995) (interpreting later cases as requiring only a "subs tantial risk of misidentification").

11degree of attention, which was arguably impaired by other

people and events he witnessed at that time.5

The government replied that Sergeant Gubbei's testi mony showed that he had only reviewed the materials cont aining Mr. Mathis's photograph once or twice, immediately after receiving them approximately a month before the Sun National Bank robbery. Furthermore, Sergeant Gubbei stated he had attended most closely to the suspects ' modi operandorum, not to their photographs. The governme nt also noted that Sergeant Gubbei described his view of Mr.

Mathis's face on October 14 as unobstructed and cle ar, and that he exhibited both a high degree of attention i n watching the Jeep's occupants disembark and a high level of certainty in making his subsequent photographic

identification.

In denying Mr. Mathis's motion to exclude the testi mony, the District Court followed this court's two-step p rocess for applying Biggers:

The first question is whether the initial id entification procedure was `unnecessarily' . . . suggesti ve. This inquiry . . . contains two component parts: that concerning the suggestiveness of the identif ication, and that concerning whether there was some good reason for the failure to resort to less suggestive procedures. If a procedure is found . . . unnecessarily sug gestive, the next question is whether the procedure . . . gave rise to

such a `substantial likelihood of . . . misi dentification' that admitting the identification would be a denial of due process.

United States v. Stevens, 935 F.2d 1380, 1389 (3d C ir. 1991) (internal quotation omitted). The District Co urt ruled that Mr. Mathis did not "initially demonstrate[that ] the identification was impermissibly suggestive"; the D istrict Court then proceeded to find that Sergeant Gubbei's identification was reliably based in fact and most likely did

___________________________________________________ ______________

5. Mr. Mathis conceded that Biggers's"length of tim e" factor weighed in favor of admitting the evidence, since the conteste d identification occurred just one day after Sergeant Gubbei viewed the Jeep's

passenger.

12not result from impermissible suggestion. The Distr ict

Court also found that the "background of the photo of the defendant is no darker or lighter than the other ph otos," that the cropped pictures did not reveal any differ ence in the subjects' build, and that the eight men "have t he same skin tone, have the same facial features, eyes, nos e, lip shape, [and] facial hair."

We review the District Court's decision for abuse o f discretion, applying clear error review to its unde rlying factual findings and plenary review to its conclusi ons drawn from such facts. United States v. Emanuele , 51 F.3d 1123, 1127 (3d Cir. 1995); see also Sumner v. Mata, 455 U.S. 591, 597 (1982) (discussing the relationship b etween fact and law in the context of pretrial identificat ions). On appeal, both parties have primarily disputed the fa ctual reliability of Sergeant Gubbei's identification and whether

there existed a substantial likelihood of misidenti fication. We affirm, however, based solely on the first part of the Stevens test, i.e., the District Court's determinat ion that Mr. Mathis did not show the photographic identifica tion to be unnecessarily suggestive. See United States v. H ill, 967 F.2d 226, 230 (6th Cir. 1992) (noting the defendant 's burden of proof on this issue).

Mr. Mathis contends, as he did before the District Court, that "a photographic array created for purposes of a bank robbery investigation--which consists of seven phot os the witness has never seen before, and one photo the wi tness has seen before in the very context of a bank robbe ry investigation--is by its very nature unduly suggest ive." Appellant's Br. at 14. We disagree, finding that, w ithout more, this allegation speaks only to the weight of the evidence and, thus, may properly be argued to the j ury--as Mr. Mathis did in this case. Cf. Manson v. Braithwa ite, 432 U.S. 98, 116 (1977) ("[E]vidence with some element of untrustworthiness is customary grist for the jury m ill. Juries are not so susceptible that they cannot meas ure intelligently the weight of identification testimon y that has some questionable feature."). The unadorned fact th at Sergeant Gubbei briefly viewed Mr. Mathis's picture , as part

of a collection of materials distributed one month before the robbery, does not demonstrate sufficient suggestive ness to

13require constitutional inquiry into whether a

misidentification might have occurred in this case.

Since we have not discovered cases squarely address ing facts like these, we are primarily guided by princi ples articulated in Stevens, 935 F.2d at 1380, where the defendant's picture was selected from a photographi c array by two witnesses who had previously identified the defendant from a police station's wanted board. Tha t board, to which the witnesses were directed by a police of ficer as they filed their complaint, contained eight posters ."[F]ive were composite sketches, one contained eight small photographs, and the other two were both photograph s of [the defendant]. . . . [O]ne of his photographs was in color, whereas the other nine photographs were in black an d white." Id. at 1388. In evaluating the suggestivene ss of the board's collection of photographs, we acknowledged that the wanted board had "several suggestive attributes ": "Whereas the posters of Stevens each contained photographs, most of the other posters had only com posite sketches. Stevens's picture, moreover, was the only one that appeared twice . . . . Even more bothersome . .. are that Stevens's photographs were significantly large r than the others, and that Stevens was the only suspect portrayed in color." Id. at 1390. Each of these fea tures "quite possibly could have drawn the victims' atten tion to Stevens" independent of the witnesses' recollection . Id. But

we also noted certain considerations that counseled against deeming such suggestiveness "unnecessary," includin g the fact that the wanted board had not been "arranged w ith this particular crime in mind. It was, rather, a co llection of random sketches and photographs that had been

assembled in order to facilitate chance identificat ions . . . ." Id. Measured against this general law enforcement p urpose, we also noted that wanted boards often cannot be ma de with photographs of uniform size. Thus, although as pects of the particular wanted board in Stevens were unnecessarily suggestive, we made significant effor ts to stress that such displays generally are not so. Com pare id.

with id. at 1390 n.12.

Here, the materials that Sergeant Gubbei received w ere apparently assembled for a law enforcement purpose whose

14validity is not challenged. Such materials obviousl y were

not prepared or circulated with the Sun National Ba nk robbery (which occurred thereafter) in mind, nor, i t seems, with awareness of influencing any photographic identification procedures. Cf. Emanuele, 51 F.3d at 1129 ("[W]e expressly do not require defendant to establ ish the government's state of mind. On the other hand, evid ence that the government intended and arranged such [a potentially suggestive] encounter would be a substa ntial factor in the court's analysis."). We hold that, wi th respect to the present facts, due process does not protect defendants like Mr. Mathis from photographic materi als briefly viewed one month before the disputed identi fication, when such materials are distributed only for purpos es of general law enforcement. The brief time that elapse d between Sergeant Gubbei's receiving the materials a nd his selecting Mr. Mathis's picture from the photographi c array significantly reduces the level of cognizable "sugg estiveness" at issue. And though it might seem preferable, or e ven more effective, for police departments to use photograph s in identification arrays that are different from those used in previously distributed suspect data, we do not find an identification "unnecessarily suggestive" simply be cause the same photograph, or a very similar photograph, is u sed in both. Law enforcement agencies commonly lack an abundance of particular suspects' photographs for u se in assembling photographic arrays. And even where vari ous pictures are on hand, lists are not often kept reco rding which pictures have been circulated to officers who later happen to be eyewitnesses. Given such operational circumstances--similar to those concerning police s tation wanted boards--we cannot agree that Sergeant Gubbei 's prior exposure to Mr. Mathis's photograph, in and o f itself, renders his subsequent identification unnecessarily suggestive.

Mr. Mathis further claims that certain "additional circumstances" aggravated the suggestiveness of Ser geant Gubbei's photographic identification. First, Mr. Ma this notes that Sergeant Gubbei chose Mr. Mathis's photo graph only after Mr. Gantt had already identified one of his coconspirators by name as "Mr. Mathis." We agree with the government, however, that there is no evidence to c onnect

15Mr. Gantt's identification of Mr. Mathis by name wi th

Sergeant Gubbei's identification of Mr. Mathis by i mage. Since the photographic array did not list the names of its subjects, Mr. Mathis has failed to show how Mr. Gan tt's prior identification by name increased the photogra phic array's suggestiveness. Second, Mr. Mathis claims t hat, of the eight photographs in the array, Mr. Mathis's pi cture "quite obviously" was the only one of a "slender an d slight"

build. We review for clear error the District Court 's factual finding to the contrary, and we find none. The arra y at issue portrays only the subjects' heads and necks, making their general physiques very difficult to estimate. Even from this limited view, however, it seems that at least two other photographs depict men of a build similar to Mr. Ma this's. Third, Mr. Mathis claims that the background of Mr. Mathis's photograph "was noticeably darker than the remaining seven." Upon reviewing the array, we agre e and find the District Court's finding to the contrary c learly erroneous; thus, we must assess the impact of this circumstance on the alleged "unnecessary suggestive ness" of Sergeant Gubbei's identification. Although Mr. M athis's picture is darker than the others in the array, the re are at least three other pictures whose backgrounds are somewhat dark. Given the current technological stat e of photographic reproduction, and the variety of backg rounds evident in the eight pictures at issue, we hold tha t the slightly darker background of Mr. Mathis's picture did not significantly contribute to the array's unnecessary suggestiveness. See United States v. Burdeau, 168 F .3d 352, 357 (9th Cir. 1999).

In sum, we find that Sergeant Gubbei's photographic identification was not "unnecessarily suggestive" t o the degree required by Biggers. Due process does not ma ndate the removal of testimony like Sergeant Gubbei's fro m the jury's consideration, even if such evidence present s (as much admissible evidence does) a risk of misidentif ication. On the contrary, such modest levels of "suggestiven ess," which are not deemed constitutionally "unnecessary, " speak only to the evidence's ultimate reliability a nd should therefore be argued for authoritative appraisal to the factfinder. On the current record, we find no abuse of

16discretion in the District Court's decision to admi t Sergeant

Gubbei's testimony into evidence.

C. Expert Testimony Regarding Eyewitnesses

After the government had presented its witnesses, M r. Mathis sought to present testimony from Dr. Geoffre y Loftus regarding the reliability of eyewitness iden tifications such as Sergeant Gubbei's. The District Court condu cted an evidentiary hearing to determine whether such testimony was admissible. During that hearing, Dr. Loftus testified that he had received a doctoral degree fr om Samford University in clinical psychology and had s erved as a professor at the University of Washington for ove r twentyfive years. His doctoral dissertation concerned hum ans' ability to recall and recognize pictures from memor y, and his subsequent studies in the field of human percep tion and scientific methodology were published as books and professional journal articles. Based on these and o ther academic credentials, the District Court qualified Dr. Loftus as an expert in the field of human perception and m emory.

Dr. Loftus then proffered testimony on four topics concerning the operation of human memory: (i) the preconditions for forming accurate memories, (ii) t he confounding impact of "double identification" or "p ost-event information," (iii) the relationship between indivi duals' confidence in describing memories and the accuracy of such memories, and (iv) potential disruptions cause d by "weapons focus." With respect to memory formation, Dr. Loftus observed that, among other circumstances, th e brevity of one's visual exposure to an object tends to cause an incomplete memory, which might later be especial ly susceptible to biasing influences. Dr. Loftus desc ribed "double identification" as a problem in determining whether one's memory derives from one of two or more possib le visual exposures to an object. According to Dr. Lof tus, a witness's recognizing someone, under circumstances similar to those described by Sergeant Gubbei, coul d derive either from the witness's actually having seen the recognized person or from a previous exposure to th at person's photograph. Dr. Loftus indicated, citing s cientific studies, that when one encounters a remembered imag e along with "post-event information" suggesting a pa rticular

17context from which the image might be remembered (s uch

as the Sun National Bank robbery's photographic arr ay), such post-event information can become incorporated with the original memory, creating an inaccurately "remembered" association between the image and its source. Regarding witnesses' confidence in their identifications, Dr. Loftus stated that "the corres pondence between confidence and accuracy is, at best, about 25 percent." He further explained that when conditions attending the recalled memories are poor, "when, fo r example, there is only a brief duration . . . [or] incorrect post-event information introduced to the [observer] , it's

under those circumstances that the relation between confidence and [accurate] memory is zero." And on t he topic of "weapons focus," Dr. Loftus discussed studies fi nding that the presence of a dangerous weapon can weaken one's ability to recall other aspects of a remembered sce ne, including individuals present therein.

In applying these principles to hypothetical questi ons intended to simulate the facts of this case, Dr. Lo ftus stated that "it's two to three times as likely that the id entification in the photo montage was made based on seeing the photograph four weeks earlier than it was based on seeing the individual" who fled on October 14, 1998. Dr. L oftus also concluded that, if the photo array did not act ually depict the person who exited the Jeep, that array i tself would constitute incorrect post-event information. And such misinformation might have caused Sergeant Gubb ei's

identification of Mr. Mathis to reflect the man see n in the previously viewed photograph, who was observed unde r conditions favorable to memory formation, rather th an the man seen running away, who was observed under conditions unfavorable to memory formation. Dr. Lof tus further opined that the officer's confidence in thi s identification and the factual accuracy thereof wou ld have a probabilistic relationship of "essentially zero" under such

circumstances.

Mr. Mathis moved to admit the foregoing testimony i nto evidence pursuant to Federal Rule of Evidence 702, which provides:

18If scientific, technical, or other specializ ed knowledge

will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness q ualified as an expert . . . may testify thereto in the f orm of an opinion or otherwise, if (1) the testimony i s 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 relia bly to the

facts of the case.

Fed. R. Evid. 702. In particular, Mr. Mathis argued that Dr. Loftus's testimony was based on generally accepted scientific methods and data, that there was a direc t relation between the proffered testimony and the factual iss ues in dispute, and that the proffered testimony would"ref ute common assumptions about the reliability of eye wit ness identification testimony that will assist the jury to weigh the credibility of Sergeant Gubbei's eye witness

identification."

The District Court excluded Dr. Loftus's testimony, but it ratified Dr. Loftus's qualifications as an expert a nd dismissed all methodological challenges to the stud ies he cited. The following constitutes the District Court 's explanation of its ruling:

I'm particularly concerned with [Rule] 403 a nd I'm inclined not to allow this testimony. I beli eve this testimony has the probability of confusing a nd misleading the jury. I find no problem with his qualifications. Obviously he is qualified in this area.

The debate over the differences in the studi es is an interesting academic debate. As [defense cou nsel] points out, however, there is only one [w]ay to run the

studies. You can't run them in a live situat ion, they

have to be in a controlled situation. That d oes not give

me pause.

What does give me pause is the fact that I b elieve that in point of fact, there is a probability tha t there will be unfair prejudice here. The aura of reliabili ty that's attached to an expert witness, I believe, is significant. Listening to this expert, it seems to me, th at the testimony itself has the potential, if not c ontrolling

19probability of confusing the jury. There is no issue in

this case about cross-racial identification. There is no issue about stress. They were the two more c ompelling

issues about which I was concerned.

The issues concerning the focus at the time of the

chase and when the defendant exited the vehi cle are subject to the jury. The defense in this cas e had an untrammeled opportunity to cross and did, in fact, cross the police officer vigorously on that area. The testimony is, I think clear. Whether the jur y accepts it or not, how the jury accepts it is clearly w ithin their province. I do not see how this evidence wil l do anything, other than to confuse and mislead the jury.

I decline the invitation to admit.

1. Admissibility of Dr. Loftuss Testimony

We review the District Court's decision to exclude Dr. Loftus's testimony for abuse of discretion. General Electric Co. v. Joiner, 522 U.S. 136, 143 (1997); Oddi v. Fo rd Motor Corp., 234 F.3d 136, 146 (3d Cir. 2000). Although t he District Court explicitly rested its decision on Ru le 403's standards for probative value and prejudice, the government on appeal invokes only Rule 702's prescr iptions regarding expert testimony. We will address both ru les, beginning with Rule 702.

This court has construed Rule 702 as embodying "thr ee distinct substantive restrictions on the admission of expert testimony: qualifications, reliability, and fit." E lcock v. Kmart Corp., 233 F.3d 734, 741 (3d Cir. 2000). Only "fit" is contested here; the government acknowledges that Dr

. Loftus is a properly qualified expert and that his methods, principles, and data are of a sufficiently reliable scientific character. See generally Daubert v. Merrell Dow Pha rm., 509 U.S. 579, 592-94 (1993) (discussing factors tha t may be considered in assessing scientific reliability); In re Paoli R.R. Yard PCB Litig., 35 F.3d 717, 742 n.8 (3d Cir. 1994) (same).

Rule 702's fit requirement derives from the textual provision that "scientific, technical, or other spe cialized knowledge will assist the trier of fact to understa nd the

evidence or to determine a fact in issue." Fed. R. Evid. 702.

20The requirement is "not intended to be a high one,"

however, Oddi, 234 F.3d at 145, and its principle i s not dissimilar to the Federal Rules' general provision that, unless otherwise specified, "[a]ll relevant evidenc e is admissible" and "[e]vidence which is not relevant i s not admissible." Fed. R. Evid. 402; Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999) (interpreting Rule 702 as requiring all expert testimony to be relevant and r eliable). Compare United States v. Downing, 753 F.2d 1224, 12 30 (3d Cir. 1985) (noting "the liberal standard of adm issibility mandated by Rule 702"), with Daubert, 509 U.S. at 5 87 (noting that Rule 402's "basic standard of relevanc e is a liberal one"). See generally Daubert, 509 U.S. at 5 92 (describing inquiry under Rule 702 as a determinati on "of whether the reasoning or methodology underlying the testimony is scientifically valid and of whether th at reasoning or methodology properly can be applied to the facts in issue").

The clearest guide for interpreting Rule 702 in the context of this case is United States v. Downing , 753 F.2d at 1226, wherein this court, in 1985, first conside red the admissibility of expert testimony concerning human memory and eyewitness testimony. In Downing, we discussed certain of the rationales advanced by oth er courts of appeals in prior years for excluding such testimony, including notions that relevant issues c ould adequately be raised through cross-examination and common sense, that such testimony usurps the jury's function, and that such evidence would lead to an u nduly confusing "battle" of experts. Id. at 1229-30 & n.4 . In explaining why we found those rationales unpersuasi ve, we disavowed skepticism of such testimony as a matter of principle, and we remanded for the district court t o apply Rule 702's "helpfulness test." We described this te st, in pertinent part, as follows: "[A]dmission depends up on the `fit,' i.e., upon a specific proffer showing that s cientific research has established that particular features o f the eyewitness identifications involved may have impair ed the accuracy of those identifications." Id. at 1226.

In the case at bar, the government challenges the f it of Dr. Loftus's testimony in three respects. First, on the

21subject of "double identification" and "post-event

information," the government claims that Dr. Loftus 's testimony did not pertain to the present facts beca use, according to Dr. Loftus's own theory, Sergeant Gubb ei viewed Mr. Mathis's face only once, as part of the suspect materials, before selecting from the photographic a rray. Thus, the government claims, this case did not invo lve any "double" identification. Appellee Br. at 36. The go vernment also argues that there was no post-event informatio n "between the visual identification of Mathis on the day of the robbery and the photo array identification." Id . at 38. Each of these arguments misconstrues the substance of Dr. Loftus's testimony. As explained supra, double identification theory indicates that a person confr onting an image may have a firm memory of having previously v iewed the image, but may not have a similarly firm memory of when that viewing occurred. Given the suboptimal conditions for memory formation during the Jeep inc ident, and given the relative calm under which Sergeant Gu bbei had previously seen a photograph of Mr. Mathis, Dr. Loftus testified that Sergeant Gubbei might have recalled Mr. Mathis's face from that previously viewed photograp h but--because he was searching the photographic arra y in order to identify the Jeep's passenger--he might ha ve wrongly associated the recalled photographic image with the fleeing robbery suspect. Contrary to the govern ment's misunderstanding, the two pertinent "identification s" were the view of the suspect materials and the view of t he man

who fled.

Furthermore, according to Dr. Loftus, the photograp hic array constituted potentially inaccurate post-event information, which might have influenced Sergeant G ubbei wrongly to associate Mr. Mathis's image with the Su n National Robbery.6 Dr. Loftus also was of the view that

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6. The government argues that the photographic arra y was not distortive post-event information if, as we have now held, the array was not unconstitutionally suggestive. As our earlier discu ssion makes clear, however, the standards of "unnecessary suggestivene ss" for admissibility under Biggers simply have no bearing on Dr. Loftus' s testimony. A photographic identification may be highly suggestiv e as a psychological matter and still be deemed legally admissible as a constitutional one. A

determination that such an identification is admiss ible poses no greater barrier to attack by expert testimony than it does to cross-examination.

22Sergeant Gubbei's act of choosing Mr. Mathis's phot ograph

from the several photographs constituting the photo array was itself post-event information that could have i nfluenced Sergeant Gubbei's face-to-face identification of Mr . Mathis at trial. Dr. Loftus argued that these pieces of po st-event information may have distorted each of Sergeant Gub bei's purported identifications of Mr. Mathis. Given the close correspondence between these aspects of Dr. Loftus' s testimony and the factual issues disputed at trial, we conclude that the proffered evidence did not lack evidentiary fit for purposes of Rule 702.

Second, the government contends that Dr. Loftus's observations with respect to the weak relationship between an eyewitness's testimonial confidence and the accu racy of such testimony did not fit because, in the governme nt's view, Dr. Loftus presented "nothing more than a gen eral

thesis on the correlation between confidence and ac curacy." Id. at 44. As an initial matter, this characterizat ion of the evidence appears mistaken. Dr. Loftus testified abo ut the relationship between confidence and accuracy under specific circumstances similar to those in this cas e: an identification based on a brief view, in the presen ce of a deadly weapon, and several potentially distracting events on-going. Also, Sergeant Gubbei's testimony on dire ct examination indirectly implicated his confidence as an element supporting the credibility of his identific ation. In describing how he selected Mr. Mathis's photograph, Sergeant Gubbei was asked, "Q: Did you have any hesitation in determining those individuals [Mr. Ma this and Mr. Gantt]? A: No, I didn't." Later, after already having described his choice of Mr. Mathis's photograph fro m the array, Sergeant Gubbei was again asked, "Q: Sitting here today Sergeant, was your identification of Keith Ma this from the photo array based upon your viewing him th e day before, following the bank robbery or on the photog raph that you had been shown in the packet? A: I identif ied him from the incident that took place from the Sun Nati onal on the day before." The level of confidence underlying Sergeant Gubbei's identification came into more explicit foc us during

cross-examination:

Q: [A]s we sit here today, is it even possib le that the identification you made of Mr. Mathis in tha t photo

23array was based not on seeing him exiting th at Jeep

but on the previous opportunity to observe t hat photograph.

A: No, I'm positive by him getting out of th e vehicle

. . . .

Q: Your answer is it's not even a possibilit y?

A: I guess there is a remote possibility, bu t I'm positive

of the identification when he exited the veh icle.

Where Sergeant Gubbei testified so directly regardi ng his high confidence in the disputed identification, it seems clear that Dr. Loftus's testimony did address, for purposes of Rule 702, pertinent factual disputes in the case . See Stevens, 935 F.2d at 1400 (reaching an identical co nclusion where the defendant sought "[t]o rebut the natural assumption that [the witnesses'] strong expression of confidence indicates an unusually reliable identifi cation").

Third, the government argues that Dr. Loftus's opin ions about "weapons focus" were not relevant to the pres ent case because Sergeant Gubbei was a police officer w ho was quite accustomed to firearms, and because the relev ant gun was pointed into the air, not at Sergeant Gubbei. S uch arguments may be useful topics for cross-examinatio n, but we do not find them persuasive grounds for exclusio n under Rule 702. Dr. Loftus expressed the view that the phenomenon of weapons focus derives both from the infrequency with which most individuals view deadly weapons and from a survival instinct that draws one 's attention to potentially threatening objects. He po inted out that various studies, performed by him and by other scientists, showed that a weapon's presence in a sc ene substantially affects subjects' ability to recall i ndividuals in that scene. He further pointed out that close physi cal proximity of a weapon to another object (e.g. , the face of the Jeep's passenger) would not appreciably reduce the weapon's distortive influence on a witness's memory

.

With respect to Sergeant Gubbei's being a police of ficer, Dr. Loftus acknowledged that one's degree of famili arity or unfamiliarity with the weapon at issue generally wo uld affect the practical impact of weapons focus. But D r. Loftus

24also noted that the primary study on which he relie d

involved a knife, which, in his view, was an adequa tely familiar object for most people. Moreover, Dr. Loft us specifically rejected any notion that police office rs would be immune to the psychological principles he described . With respect to the particular location of the gun, Dr. Loftus indicated that psychological studies inevitably tak e place in secure environments; thus, all of the cited studies assumed observers who were actually safe from the weapon at issue. He observed that the "survival" impetus for weapons focus would, in real life situations, likely be even high er than the cited studies indicated. Thus, we cannot agree with the government's suggestion that Dr. Loftus's expert op inions regarding weapons focus were not relevant for purpo ses of

Rule 702.

Having concluded that the government's arguments fo r exclusion under Rule 702 cannot succeed, we turn no w to Rule 403. As an initial matter, "[w]e are mindful t hat a trial court is in a far better position than an appellate court to strike the sensitive balance dictated by Rule 403. When a trial court engages in such a balancing process and

articulates on the record the rationale for its con clusion, its conclusion should rarely be disturbed." Pinney, 967 F.2d at 918; see also Downing, 753 F.2d at 1242-43 (noting Rule 403's important role in assessing whether expert testimony's probative value is "substantially outwe ighed by other dangers, e.g., confusion of the issue or wast e of time"). But when a district court does not explain its ruling, and no adequate explanation can be gleaned from the record, appellate courts often have little choice b ut to undertake such evaluation themselves. See e.g. , Un ited States v. Murray, 103 F.3d 310, 319 (3d Cir. 1997) (noting that when district courts fail to explain their rul ings under Rule 403, "we are able to perform this balancing he re, [though] other cases may require remand . . . or ev en . . . a new trial"); United States v. Himelwright , 42 F. 3d 777, 785 (3d Cir. 1994).

We find it difficult to accord the customary degree of

deference to the District Court's discretion in thi s case because the District Court explained its ruling wit h little

more than a series of conclusions:

25[T]his testimony has the probability of conf using and

misleading the jury. . . . [T]here is a prob ability that there will be unfair prejudice here. The aur a of reliability that's attached to an expert wit ness, I believe, is significant. Listening to this e xpert, it seems to me, that the testimony itself has the pot ential, if not controlling probability of confusing the jur y. . . . [Sergeant Gubbei's] testimony is, I think, c lear. Whether the jury accepts it or not, how the jury accepts it is clearly within their province. I do not see how this evidence will do anything, other th an to confuse and mislead the jury.

The District Court clearly expressed concern with"[ t]he aura of reliability that's attached to an expert

witness"--which is one reason for district courts' "gatekeeping function" in assessing expert testimon y under Rule 702. See Daubert, 509 U.S. at 592, 594. There is no suggestion, however, that such an aura of reliabili ty was unwarranted in this case or, to be more precise, th at it was unfairly prejudicial. From the record, it seems tha t Dr. Loftus was an extremely qualified, experienced acad emic presenting opinions on topics near the heart of his expertise. Moreover, Dr. Loftus's conclusions seem closely tied to empirical studies whose reliability is not impeached, and he explained the bases for these studies at app arently appropriate length. In short, we see no reason to b elieve that Dr. Loftus's aura of reliability reflected any thing other than his actual reliability as an expert witness. W ith respect to the District Court's concern with "confu sing and misleading the jury" and "unfair prejudice," we are unable to discern from these references, any more than fro m our own review of the record, how such problems might a rise.

The government's oral argument before the District Court also fails to reveal any valid basis for exclusion under Rule 403. The government focused on two contentions. Fir st, it claimed that the studies cited by Dr. Loftus did no t sufficiently match the circumstances of this case. The District Court rejected this position, holding that such disputes "did not give [him] pause," and the govern ment has conceded this issue on appeal.

Second, the government stated that:

26[T]he problem that bothers me most, your Hon or, is the

danger of overwhelming the jury. When we gav e this witness a hypothetical that was slightly--yo u know, everyone in this courtroom knows the facts b etter than I do, but [it] sounded to me slightly tinged toward the defense version of the offense, the witness stated as a fact that the sergeant would not remember ac curately. When I gave him the version that was a littl e bit closer

to what I believe the facts to be and the Go vernment version, he stated as a fact that his conclu sion would be very different under those facts. So what he's doing is telling the jury the answer instead of al lowing the jury to determine the facts for themselves. Any hypothetical that sets forth those facts is likely to have a serious effect on the jury's memory of the testimony rather than allowing the jury to decide what the jury's going to decide.

The full significance of this language is not clear . In part, the objection apparently derives from the fact that Dr. Loftus's answers regarding Sergeant Gubbei's memory changed when the hypotheses under consideration wer e altered regarding, for example, the number of secon ds Sergeant Gubbei saw the fleeing man's face and the attention Sergeant Gubbei paid to the distributed s uspect materials. Some might view such a change in an expe rt's analysis as the reward of a successful cross-examin ation; it

seems hard to view such variation as a basis for ex cluding the testimony under Rule 403. The government did no t demonstrate, and has not done so now, how this dime nsion of Dr. Loftus's testimony tended to cause any artic ulable degree of unfair prejudice, confusion, or delay.

Another aspect of the government's objection stems from a concern, which the District Court seemingly share d, that Dr. Loftus's testimony might usurp the jury's funct ion. Insofar as this argument constitutes a general atta ck on expert testimony concerning eyewitness identificati ons, such issues are largely resolved by Downing. See id . at 1229-30 & n.4. Similar to other types of expert wit nesses, who might testify about the flaws of a computerized filing system or the proper interpretation of satellite ph otographs, experts who apply reliable scientific expertise to juridically

27pertinent aspects of the human mind and body should

generally, absent explicable reasons to the contrar y, be welcomed by federal courts, not turned away. Cf. Un ited States v. Smithers, 212 F.3d 306, 311-12 & n.1 (6th Cir. 2000) (describing a judicial trend toward, and an empirically supported need for, accepting expert te stimony about eyewitness identification). In this case, Dr. Loftus made quite clear that he did not intend to tell the jury whether Sergeant Gubbei was lying or telling the tr uth. Like more typical sorts of expert witnesses, Dr. Loftus attempted to provide information that, if itself deemed credi ble, might cause the jury to evaluate Sergeant Gubbei's testim ony in a different light.

In analyzing for ourselves whether the four compone nts of Dr. Loftus's testimony7 were admissible, we foll ow standards set forth in United States v. Stevens , w hich is also discussed supra in Part II.B. In Stevens, the defendant proffered expert testimony on six topics: "(1) the accuracy of cross-racial identifications; (2) the effect of wea pon focus on identifications; (3) the effect of stress on identi fications; (4) the suggestiveness of the wanted board [from which the defendant was initially identified]; (5) the relati on back of subsequent identifications to the initial identific ation; and (6) the lack of correlation between confidence and accuracy in eyewitness identifications." 935 F.2d at 1397. T he district court permitted expert testimony on the fi rst three, but excluded testimony on the remainder.

On appeal, the Stevens court affirmed the exclusion of proffered testimony regarding the wanted board's "suggestiveness," in deference to the district cour t's determination that " `[t]he fact that there are two pictures . . . of the same person and one [is] in color, I t hink[,] . . . is certainly apparent [to] the jury . . . for the jury to make its own determination.' " Id. at 1399; cf. United S tates v. Gibbs, 190 F.3d 188, 212 (3d Cir. 1999) ("We have u pheld the exclusion of expert testimony when that testimo ny ventures into areas in which the jury needs no aid or illumination."). Similarly, in this case, Dr. Loftu s's

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7. Memory formation, double identification and post -event information, the relationship between confidence and accuracy, a nd weapons focus.

28testimony--claiming that more accurate memories are

produced by objects that are viewed for longer peri ods of time--is not the type of information that, in and o f itself, would warrant exposition by an expert witness; thus , we concur in the District Court's decision to exclude such testimony under Rule 403.8

Stevens's expert testimony regarding "relation back " apparently explained that "once a witness makes an identification, he or she will tend to stick with t hat initial choice at subsequent photographic arrays or lineups , even if it was erroneous." Stevens, 935 F.2d at 1399. Su ch evidence closely resembles the part of Dr. Loftus's testimony on "double identification" and "post-even t information" that explained how, after Sergeant Gub bei had already selected Mr. Mathis's picture from the arra y, his incourt identification was likely to be consistent th erewith, regardless of any actual memory of the underlying e vents. In Stevens, we affirmed the exclusion of expert tes timony on this topic because we found the testimony "rathe r pedestrian" and "susceptible of elucidation without specialized knowledge." Id. at 1399-1400. We are bo und to reach a parallel conclusion here; hence, we affirm the exclusion of Dr. Loftus's testimony on this subject

.

Another portion of Dr. Loftus's discussion of "doub le identification," however, was significantly more co mplex than the testimony at issue in Stevens. In particul ar, Dr. Loftus described studies in which subjects remember ed having seen an image, but, upon being asked to asso ciate that image with one of two times they might possibl y have seen it, the subjects often "remembered" inaccurate ly. Dr. Loftus further explained how Sergeant Gubbei might have clearly remembered Mr. Mathis's face from having previously seen a photograph of Mr. Mathis, but mig ht have confidently and incorrectly associated that memory with the

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8. We do not mean to bar, by this determination, th e strong possibility that parts of Dr. Loftus's account of memory format ion might have been properly admissible as a necessary precursor, or an cillary, to other admissible testimony regarding memory. Our ruling m erely indicates that such testimony, in and of itself, does not nec essarily surmount the

barrier of Rule 403.

29previous day's fleeing suspect. Dr. Loftus indicate d that

such a misidentification was peculiarly likely in circumstances where one possible event-memory association (the previously viewed photograph) invo lved favorable conditions for memory formation and invol ved the same visual medium as the image to be identified (a photograph), whereas the other event-memory associa tion (the robbers' escape) involved unfavorable memoryconditions and a different visual medium (threedimensional observation). We believe that testimony of this sort, with its accompanying level of scientific det ail, would not simply duplicate jurors' intuitions or common s ense, and such principles seem difficult to establish ind irectly through cross-examination. Accordingly, we find tha t the District Court abused its discretion in excluding s uch testimony.

The third type of testimony analyzed in Stevens concerned the relationship between an eyewitness's confidence and the accuracy of a resultant identifi cation. Dr. Loftus opined on this same topic in the present case, stating that the correspondence between confidence and accuracy is "at best, about 25 percent" and, under circumstances like these, is "essentially zero." In Stevens, we held that such information was sufficiently illu minative and susceptible to scientific expertise that exclus ion was unacceptable under "the liberal standard of admissi bility of Rule 702" and Rule 403. Id. at 1400-01. In the pres ent case, the government objects that Stevens cannot "m ean that [any time] an eyewitness has confidence in his identification, a defendant is automatically entitl ed to present testimony that confidence has little or no correlation to accuracy." Appellee's Br. at 43. We agree that Stevens did not establish such a universally applic able rule, and we also decline to do so here. As the governmen t correctly notes, analysis under Rules 702 and 403 i s factintensive and case-specific. That said, however, St evens did hold that, when expert testimony of this character satisfies the reliability and fit requirements of Rule 702, a nd when there is no countervailing rationale for excluding the evidence under Rule 403, the evidence must be admit ted. In light of our findings regarding this evidence's probative value and our inability to discover any offsetting prejudice,

30confusion, or delay, we hold that the District Cour t abused

its discretion in failing to admit Dr. Loftus's tes timony on the relationship between eyewitness confidence and

accuracy.

The final topic discussed by Dr. Loftus was "weapon s focus." In Stevens, this issue was not before us be cause the District Court had admitted expert testimony on the subject. In light of the principles decided in Stev ens, as well as those discussed supra, we find that Dr. Loftus's proposed testimony regarding weapons focus should h ave been admitted into evidence. The government argues that a jury does not need expert testimony to learn "the i dea that one might be distracted by a weapon." Appellee's Br . at 34. But Dr. Loftus's testimony was not limited to such a narrow scope. In combination, the studies he discussed ind icated that the presence of weapons weakened memories of o ther aspects of an observed scene, even when such weapon s posed no immediate threat, and even when those weap ons' images might be located quite near the object later to be identified. We find that the degree and scope of me mory distortion that, according to Dr. Loftus, a weapon typically causes for eyewitnesses are not matters that would necessarily be apparent to jurors. And, just as wit h the other admissible aspects of Dr. Loftus's testimony, it is difficult to comprehend how weapons' destructive ef fect on memory might be elucidated through cross-examinatio n. Especially if Dr. Loftus is correct that witnesses

remain confident of their identifications even when those identifications are inaccurate, eyewitnesses cannot be expected--even under the most skilled questioning--explicitly to recall or nonverbally to reveal the extent to which their remembered impressions might have been distorted or undermined. We find that, in this case, and on this record, it was an abuse of discretion n ot to admit such testimony into evidence.

D. Harmless Error

Our final step is to consider whether the District Court's error in excluding parts of Dr. Loftus's testimony was legally harmless. See 28 U.S.C.A. S 2111 ("In the h earing of any appeal[,] . . . the court shall give judgment a fter an examination of the record without regard to errors or

31defects which do not affect the substantial rights of the

parties."); Fed. R. Crim. P. 52(a); Fed. R. Evid. 1 03(a); Kotteakos v. United States, 328 U.S. 750 (1946). Th is court

has held that a non-constitutional error committed at trial

does not warrant reversal in circumstances where"it is highly probable that the error did not contribute t o the judgment." United States v. Helbling, 209 F.3d 226, 241 (3d Cir. 2000) (internal quotation omitted). And the ap plicable standard for " `[h]igh probability' requires that w e have a sure conviction that the error did not prejudice th e defendants. We may not simply conclude that it is m ore likely than not that the error was harmless. On the other hand, we may be firmly convinced that the error was harmless without disproving every `reasonable possi bility' of prejudice." United States v. Jannotti, 729 F.2d 213 , 220 n.2 (3d Cir. 1984) (internal citations omitted). The bu rden of demonstrating such high probability lies with the government, United States v. Adams, 2001 WL 543711 at *4 (3d Cir. May 23, 2001), but we retain our establ ished authority to affirm on any ground supported by the record, Nicini v. Morra, 212 F.3d 798, 805 (3d Cir. 2000) ( en banc);

Alexander Hamilton Life Ins. Co. of Am. v. Gov't of Virgin Islands, 757 F.2d 534, 547-58 (3d Cir. 1985).

The government contends that, even if (as we now ha ve found) the District Court wrongly failed to admit c ertain testimony from Dr. Loftus, Mr. Mathis's conviction should be affirmed because the government presented other evidence that constituted more "compelling evidence of Mathis's guilt than Sergeant Gubbei's identificatio n." Appellee's Br. at 47. In particular, the government relies on testimony from Mr. Gantt, who described his coopera tion with Mr. Mathis in robbing the Sun National Bank an d eleven other banks. According to the government, Mr

. Gantt's "tremendous opportunity to observe, speak t o, and identify Mathis was damning and far outweighed Serg eant Gubbei's testimony in importance." Id. Mr. Mathis r eplies by challenging Mr. Gantt's credibility, both noting that Mr. Gantt lied to police after his arrest and arguing t hat Mr. Gantt's plea agreement provided a motive to lie if doing so might advance Mr. Mathis's prosecution. In Mr. Math is's view, the government wrongly urges this court to"sp eculate

32that the jury would have convicted defendant . . . had it

. . . heard Dr. Loftus' testimony . . . . [T]he jur y may well have concluded that the government had failed to be ar its burden of proving beyond a reasonable doubt that .

.. [Mathis] participated in the Sun National Bank robb ery." Reply Br. at 23. In essence, the government asks th is court, apparently as a matter of first instance, to weigh the import of Mr. Gantt's testimony against that of Sergeant G ubbei's testimony, while Mr. Mathis asks us not to "specula te" about what the jury would have done if Dr. Loftus h ad

testified.

We find that neither of these suggestions, viewed i n isolation, is well-suited to our role in this appea l. As the Supreme Court held in Kotteakos:

[I]t is not the appellate court's function t o determine guilt or innocence. Nor is it to speculate u pon probable reconviction and decide according to how the speculation comes out. . . . Those judgments are exclusively for the jury . . . . But this do es not mean that the appellate court can escape altogeth er taking

account of the outcome. . . . In criminal ca uses that outcome is . . . . guilt in law, established by the judgment of laymen. And the question is, not were they right in their judgment . . . . It is rather what effect the error had or reasonably may have had upon th e jury's decision. The crucial thing is the impact of the thing done wrong on the minds of other men, not on one's own, in the total setting.

Kotteakos, 328 U.S. at 763-64. Our inquiry is not w hether

this court's members would convict Mr. Mathis on th e evidence presented, or whether we would do so based on that evidence plus Dr. Loftus's wrongly excluded te stimony. Rather, we begin with the guilty verdict the jury h as already rendered, and we determine only whether, "after an examination of the record," 28 U.S.C.A. S 2111, "it is highly probable" that the jury would have reached the same decision absent the identified error. Helbling , 20 9 F.3d at

241.

Although we believe that portions of Dr. Loftus's p roffered testimony should have been admitted, we also find t hat, in

33the context of the record as a whole, his testimony was

highly unlikely to have caused a different result. The matter is not resolved simply by noting--as the government does--that Mr. Gantt's testimony could, if believed , have had great probative force and might have constitute d more "compelling evidence" than Sergeant Gubbei's testim ony. It is certainly possible that Mr. Mathis's jury would have convicted on the basis of Mr. Gantt's testimony alo ne, but we would hesitate before terming such a result "hig hly probable." Nor is it enough to find--as Mr. Mathis urges--that skeptical jurors might, with reasonable justification, have disbelieved both Mr. Gantt and Sergeant Gubbei. Reasonable doubt is the proper test for har mless error analysis concerning constitutional rights, e. g., Neder v. United States, 527 U.S. 1, 16 (1999), but a less stringent standard regulates non-constitutional errors such a s this one, e.g., Kotteakos, 328 U.S. at 764-65; Jannotti, 729 F.2d

at 220 n.2.

The crux of our analysis derives, not from any piec e of testimony in isolation, but from the interlocking correspondence of evidence throughout the record. F or example, it is not disputed that the testimony of s everal eyewitnesses, located inside and outside the bank b uilding, confirmed Mr. Gantt's basic description of how the Sun National Bank robbery occurred. Photographs produce d from the bank's video security cameras were similar ly corroborative of this testimony. Also, Mr. Gantt's account of the robbers' foiled attempt to escape in the Jeep w as virtually identical to Sergeant Gubbei's descriptio n of the same events from the perspective of his police crui ser. Mr. Gantt's identification of Mr. Seaberry as one of th e coconspirators was confirmed by an arresting officer' s testimony that Mr. Seaberry was apprehended near th e stalled Jeep, and the arrest of Mr. Seaberry also t ended to

corroborate Mr. Gantt's account of how he and Mr. M athis (but not Mr. Seaberry) finally escaped.

Giving Dr. Loftus's testimony its full weight, a ju ry might have had reasonable cause to doubt Sergeant Gubbei' s description of events, if such description were vie wed in isolation. But here, where the disputed eyewitness account was repeatedly confirmed by a co-conspirator's test imony,

34and where various aspects of that co-conspirator's

testimony were in turn confirmed by other available evidence, we think it highly improbable that a jury that

voted to convict without the aid of Dr. Loftus's te stimony, would, had it heard that testimony, have reached a

different verdict.

III. Conclusion

For the foregoing reasons, the District Court's jud gment

of conviction is affirmed.

A True Copy:

Teste:

Clerk of the United States Court of Appeals

for the Third Circuit

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