In the
 United States Court of Appeals
              For the Seventh Circuit
                        ____________

No. 06-3620
UNITED STATES OF AMERICA,
                                               Plaintiff-Appellee,
                               v.

COREY L. WILLIAMS,
                                           Defendant-Appellant.
                        ____________
           Appeal from the United States District Court
                for the Central District of Illinois.
           No. 05-10091-001—Michael M. Mihm, Judge.
                        ____________
     ARGUED SEPTEMBER 5, 2007—DECIDED APRIL 14, 2008
                        ____________


  Before EASTERBROOK, Chief Judge, and WOOD and EVANS,
Circuit Judges.
   EASTERBROOK, Chief Judge. Corey Williams pleaded guilty
to armed robbery, 18 U.S.C. §1951, and possessing a
firearm during a crime of violence, 18 U.S.C. §924(c)(1). He
has been sentenced to 290 months’ imprisonment. His
conditional plea, see Fed. R. Crim. P. 11(a)(2), reserved
the right to challenge the district court’s ruling that the
testimony of eyewitnesses would be admissible at trial.
Powerful evidence connected Williams to the robbery
independent of any eyewitness, so it is not clear that he
had much to gain by his motion to suppress the identifica-
2                                                No. 06-3620

tions, but as there was no error we need not decide
whether it would have been harmless.
  Four eyewitnesses to the crime viewed a lineup that
contained six persons of roughly the same height (from five
feet six inches to five feet nine inches), facial hair, build,
and skin color as one of the two robbers who had been
described to police immediately after the crime. The six
were dressed in identical prison garb. The officer con-
ducting the lineup told the witnesses not to assume that
one of the participants was a suspect, and not to assume
that the officer knew the suspect’s identity (if a suspect
was present). Three of the witnesses identified Williams
as a robber. (The fourth did not identify anyone.) The
officer obtained statements from each witness about their
degree of confidence (which ran from 99.9% for the most
confident witness to “five or six out of ten” for the least).
  The basis of the motion to suppress the identification and
prevent the witnesses from identifying Williams in court
is that, while five of the six participants in the lineup
wore navy blue slippers, the sixth wore white tennis
shoes. The person wearing the tennis shoes was Williams.
This made him stand out, counsel contended, and in-
creased the chance that he would be identified as the
robber—especially because the eyewitnesses had de-
scribed one robber as wearing white tennis shoes. Having
just one participant wear white tennis shoes made the
lineup unduly suggestive, Williams insisted. But the
district judge concluded that nothing in the record im-
plied that shoes, as opposed to facial characteristics and
build (and, for one witness, the suspect’s voice), played
a role in the identifications.
  Williams’s only argument on appeal is that the white
tennis shoes made the lineup unduly suggestive. If this is
No. 06-3620                                                 3

so, Williams still loses, because suggestiveness is only
part of the legal standard. Eyewitnesses should be pre-
vented from identifying a suspect in court only if the
pretrial procedure “was so impermissibly suggestive as
to give rise to a very substantial likelihood of irreparable
misidentification.” Simmons v. United States, 

,
384 (1968). Simmons said this about a photographic pro-
cedure; the same standard was applied to showups and
lineups by Neil v. Biggers, 

, 198 (1972), and
Manson v. Brathwaite, 

, 114 (1977). (Neil said
that the “irreparable” part of the inquiry applies only
to testimony, so an identification made at the lineup
itself could in principle be excluded even when the wit-
ness is allowed to identify the defendant at trial, but
Williams makes nothing of this.)
  Misidentification is “irreparable” when the source of the
error is so elusive that it cannot be demonstrated to a
jury, which therefore will give excessive weight to the
eyewitness testimony. Williams has never tried to show
that the effect of white tennis shoes is something that oper-
ates subconsciously, so that witnesses will be unshake-
able in their errors, or that jurors would be unable to
understand what happened and react appropriately.
Unless the misidentification is irreparable, there is no
basis for blocking the testimony. Perceptual biases and
errors are endemic to identification. See Elizabeth F. Loftus,
Eyewitness Testimony (1979); Daniel L. Schacter, The Seven
Sins of Memory 88–137 (2001). The normal way of dealing
with them is to expose the problem at trial so that a dis-
count may be applied to the testimony, rather than to
exclude relevant evidence.
  All questions about “irreparability” to one side, was
this lineup unduly suggestive in the first place? That
4                                                 No. 06-3620

depends on how clothes affect identification. Will giving
one participant an article of clothing that matches the
description of the offender lead a witness astray? Wil-
liams’s lawyer says yes; when asked why at oral argu-
ment, counsel replied “Common sense.” The prosecutor
says no; when asked why at oral argument, counsel re-
plied “Common sense.”
   If there is one thing known about eyewitness identifica-
tion, it is that “common sense” misleads more often than
it helps. See United States v. Brown, 

(7th Cir.
2006) (discussing some of the evidence). See also, e.g.,
Gary L. Wells & D.M. Murray, What can psychology say
about the Neil v. Biggers criteria for judging eyewitness iden-
tification accuracy?, 68 J. Applied Psych. 347 (1983); Timothy
P. O’Toole & Giovanna Shay, Manson v. Brathwaite
Revisited: Towards a New Rule of Decision for Due Process
Challenges to Eyewitness Identification Procedures, 41 Val. U.L.
Rev. 109 (2006). The problem with “common sense” is that
experience tells us what leads to confidence about whether
we have seen a given person before but does not pro-
vide reliable ways to test whether that confidence is
justified. People confuse certitude with accuracy and so
are led astray. Psychologists have established that certi-
tude often is unwarranted. It takes data rather than intu-
ition to answer questions such as “can non-uniform
footgear in a lineup lead to misidentification?”
   We directed the parties to file post-argument memoranda
addressing the social-science literature. The United States
filed a helpful memorandum; Williams’s counsel in-
formed us that he had nothing to add and thus surren-
dered the opportunity to provide any empirical support
for his submissions. Perhaps there is none to be had. The
studies collected by the United States discuss optimal
No. 06-3620                                              5

identification procedures (our opinion in Brown discusses
some of this work) but do not address the question at
hand: do differences in the clothes worn by participants
in lineups lead to false identifications?
   What we do learn from the studies is that the police
acted prudently in telling the witnesses that the lineup
may have contained no suspect at all, and that the officer
conducting it may be ignorant of the suspect’s identity.
Those steps reduce the chance that witnesses will choose
someone even though they don’t remember his face,
or may follow cues from the officer rather than rely en-
tirely on their memories. See Gary L. Wells, Eyewitness
Identification Procedures: Recommendations for Lineups and
Photospreads, 22 L. & Human Behavior 603, 627–29 (1998);
Nancy M. Steblay, Social Influence in Eyewitness Recall: A
Meta-Analytic Review of Lineup Instruction Effects, 21 L. &
Human Behavior 283, 284–85 (1997). Obtaining immediate
estimates of confidence also reduced the chance of error.
People often profess greater confidence after the fact;
their memories realign to their earlier statements, so that
trial testimony may reflect more confidence than is war-
ranted. Contemporaneous estimates of confidence reduce
that risk. See Wells, Eyewitness Identification Procedures,
22 L. & Human Behavior at 630. These conclusions sup-
port the district court’s ruling, and the lack of evidence
about the effects of clothing leaves Williams without any
way to undermine that ruling.
  One more thing is worth mention. Three witnesses
identified the same person at the lineup, although they
viewed the lineup separately and there was no risk that
one person’s identification would influence the others. The
fourth did not identify anyone and could not have been
led astray by the tennis shoes. Counsel have briefed this
6                                                No. 06-3620

appeal as if it involved only one witness, but the number
of identifications supplies valuable information. Even if
the risk that any one identification would be mistaken is
substantial, the risk that multiple witnesses would
make the same error is smaller. See Newsome v. McCabe,

(7th Cir. 2003). How much smaller? Does a
cue (such as white shoes) that points to one participant
affect all witnesses, or are errors independent? If the
individual-witness error rate is 0.3, the risk that three
people will make the same mistake is 0.3 to the third
power, or 0.027, if the errors are independent. Are they?
None of the briefs mentions this question, and the pros-
ecutor’s supplemental filing does not address it. When
multiple witnesses make the same identification, it is
essential to know how likely it is that a given misiden-
tification will recur. That, too, is a subject for empirical
inquiry.
  This is not at all to say that counsel must present experts,
or even social-science evidence, in every case. Instead
judges should take account of these matters when think-
ing about the issue and informing juries. See United States
v. Hall, 

, 1118–20 (7th Cir. 1999) (concurring
opinion). Often the right disposition will be evident with
or without the aid of social science. But when lawyers’
talk is the only thing presented to the judge—as it was
here—there will rarely be a basis for overturning the
outcome, whichever way it goes. The district judge did
not err, so the conviction and sentence are
                                                  AFFIRMED.
No. 06-3620                                               7

   EVANS, Circuit Judge, concurring. I join Chief Judge
Easterbrook’s opinion in this case because it is abundantly
clear that Judge Mihm was correct when he found that
the lineup was not unduly suggestive. Because Williams
can’t get to first base, he can’t get beyond that and estab-
lish that the lineup created a substantial likelihood that
a misidentification would occur.
  I write separately simply to note that the majority
opinion gives, in my view, a bad rap to “common sense.”
I don’t think Williams’ counsel or the prosecutor were
out of line when they answered “common sense” (of
course, what’s common sense to one can be nonsensical
to someone else!) during oral argument. Assume, for
example, that a bank is robbed and several tellers report
that the robber was wearing a green sweatshirt with
“Girdwood, Alaska” on the front. Assume further that a
day or two later the tellers viewed a lineup with six
men, all roughly the same height, weight, and race of the
robber, but one was wearing a green sweatshirt with
“Girdwood, Alaska” on the front. Common sense tells
me that the lineup would be unduly suggestive. Scientific
studies would not be needed to make that point. Here,
Williams in white tennis shoes, while the others wore navy
blue slippers, is rather trivial—his shoes are a long
way away from the Girdwood, Alaska, green sweatshirt.
Common sense tells me that the shoes Williams wore did
not make his lineup unduly suggestive.




                   USCA-02-C-0072—4-14-08