An Epistemic Defense of Exclusionary Rules in the Criminal Justice System
John R. Harris
Abstract: In criminal trials jurors are charged with determining if a crime occurred,
and if so, did the defendant commit the crime. If we want jurors to get at the truth,
then we should work to ensure that they have all the relevant and reliable information
necessary to do so. It appears that exclusionary rules subvert the truth-seeking goal of
the criminal justice system. Exclusionary rules prevent the jury from being presented
with all the relevant information about the criminal case. In this paper I consider two
powerful arguments against the use of exclusionary rules, and I argue that these
arguments fail. Exclusionary rules can, and in some cases do, serve an important
epistemic purpose.
Introduction
Evidence plays an important role in our lives. If we hope to rationally answer
a question, then we will frequently, if not always, seek out evidence. When patients
suffer from ailments doctors gather evidence in order to diagnose those ailments. In
order to determine the best treatment for those illnesses doctors again rely on
evidence gathered by themselves and others. Scientific questions are frequently
answered in large part by gathering and interpreting evidence. As we all are well
aware gathering and evaluating evidence plays an indispensible part in science,
medicine, academia, and, of course, the criminal justice system.
There is no doubt that some evidentiary gathering and evaluative systems
are better than others. Most of us have a great deal of confidence in the evidence
gathered by scientists and we likely have little confidence in the practices of
astrologists. What should interest us here is what differentiates good practices from
bad. Perhaps more modestly, we should hope to identify some key practices with
respect to evidence that will make it most likely that we will be lead to truth rather
than error. Having good evidence will not guarantee that we arrive at correct
conclusions, but our prospects will be grim without it.
When attempting to answer a question we should seek out evidence, but not
everything counts as evidence. When gathering evidence to answer a question we
do not begin to gather any and all data. If I want to know if I have beer in the
refrigerator I would not begin by weighing my cats. To be sure, what my cats weigh
is evidence of something, but this is not germane to the issue at hand. So, we do not
focus our attention simply on evidence, but to be more precise we do—or should—
focus our attention on relevant evidence. That is, we focus on that subset of
available evidence that will help us answer the question at hand.
There is more to this story than just relevancy. Some evidence we may have
available to us could be relevant, but if that evidence is not trustworthy or if we are
uncertain of its trustworthiness, then we should we should give it less weight or
ignore it entirely. If Jones claims to have witnessed a crime, then we will likely think
that his testimony is relevant. Should it turn out however that Jones was impaired
in some way at the time then we should also think that the evidence he provides is
unreliable. This is simply a reminder that we want relevant and reliable evidence
when seeking the truth.
Finally, we also want to consider all the relevant, reliable evidence that we
can. If we consider only some small portion of the evidence, we may land on
spurious conclusions. We may be drawn to certain conclusions when we have
access to partial evidence that, when considered in light of all the evidence, seem
less attractive than other conclusions. Thus, we want access to comprehensive
evidence, or at least as comprehensive as we can hope for.
We need not assume this is all we want from our evidence, but relevant,
reliable, and complete evidence certainly seems like a good beginning. If the
evidence we rely on satisfied these conditions, then we are on the right track. With
these features in mind, consider what role they play in criminal proceedings and
how exclusionary rules may serve to undermine them.
Exclusionary rules serve to prohibit certain information from being
presented in (typically) criminal trials. There are numerous exclusionary rules and
they serve to exclude a wide variety of evidence. In Mapp v. Ohio the US Supreme
Court extended the Fourth Amendment protection against illegal search and seizure
to state courts (previously the Court has rules that the Fourth Amendment only
applied to Federal Courts). Effectively states are now prohibited from introducing
evidence that was gathered illegally by police. This is but one example of the sorts
of evidence that can be excluded from trials. Other examples include hearsay,
spousal privilege, recanted confessions, key witnesses pleading the Fifth, evidence
that is considered unfairly prejudicial, and instructions that forbid jurors from
taking the defendant’s silence into consideration when considering their guilt—to
name only a few.
If, however, the central function of trials is epistemic, that is to discover the
truth, then such exclusionary rules seem to be in conflict with that function.
Exclusionary rules appear to prevent juries and judges from considering all the
relevant information that may speak to the guilt or innocence of the defendant(s).
This practice seems at odds with the best practices employed by other enterprises
that take their key function to be epistemic. The scientific enterprise would be
undermined, to say the least, if scientists ignored relevant information, were
prevented from searching for further evidence, or prevented from asking questions
of those who provide key evidence, yet this is exactly what happens to jurors.
Raising questions about the curious role of exclusionary rules is by no means
a new phenomenon. Jeremy Bentham objected to many of these practices in his
essay “Rationale of Judicial Evidence, Specifically applied to the English Practice,”
but he has by no means been the last. More recently Larry Laudan and Susan Haack
have called into question the epistemic role of exclusionary rules in the US legal
system, and both worry that they do more harm, epistemically speaking, than good.1
Needless to say, there are other goals that trials serve than just epistemic,
and one may be inclined to argue that these other goals, perhaps fairness or limits
on the exercise of state power, may serve to offset the epistemic concerns that
motivate Bentham, Laudan, and Haack’s concerns. But for our purposes we will set
those aside for the time being, though I will return to these at the end of this essay,
and instead focus solely on the epistemic case against exclusionary rules. It has
often been asserted that the epistemic role of courts is their primary function.
Justice Lewis Powell wrote:
Underlying the question of guilt or innocence is an objective truth: the
defendant, in fact, did or did not commit the acts constituting the crime
See Jeremy Bentham, Rationale of Judicial Evidence, Specifically Applied to English Practice, From the
Mss. Of J. Bentham. J.S. Mill, ed. (London: Hunt and Clarke, 1827). Susan Haack, Evidence Matters:
Science, Proof, and the Truth in the Law (Cambridge: Cambridge University Press, 2014). Larry
Laudan, Truth, Error, and the Criminal Law: An Essay in Legal Epistemology (Cambridge: Cambridge
University Press, 2008).
1
charged. From the time an accused is first suspected to the time the decision
on guilt or innocence is made, our criminal justice system is designed to
enable the trier of fact to discover the truth according to law.2
If our criminal justice system is, in fact, so designed, then preventing jurors or
judges from considering all relevant information does seem curious. If exclusionary
rules do prevent jurors from considering all the relevant information, then they do
appear to undermine the core function of the criminal justice system.
In this paper I will consider the epistemic case against exclusionary rules. In
what follows I will focus primarily on Larry Laudan’s argument against exclusionary
rules. I do so because Laudan offers the most comprehensive and compelling case
against exclusionary rules in his book Truth, Error, and the Criminal Law. Laudan
does not necessarily believe that exclusionary rules are always truth thwarting, but
he believes they are highly suspect.3 Unless we can offer strong and empirically
well-supported evidence in their favor we should eliminate exclusionary rules. As it
happens Laudan is doubtful that such strong and well-supported evidence exists for
the most part. In section 1 I consider the general argument against exclusionary
rules. What we will find is that the crucial issue is whether exclusionary rules do
subvert the epistemic role of the criminal justice system. In section 2 I consider one
key line of argumentation in support this claim: exclusionary rules generally
undermine the epistemic goals of the criminal justice system. In section 3 I consider
the example of forbidding recanted confessions from being considered by the jury,
and how this may subvert the epistemic goals of a trial. In section 4 I argue that the
case against recanted confessions fails. That is, we can justify excluding recanted
2
3
Justice Lewis Powell (dissent), Bullington v Missouri, 451 U.S. 430 (1981)
Laudan, p. 122.
confessions on epistemic grounds. In section 5 I argue that the general epistemic
case against exclusionary rules also fails. Exclusionary rules do not “exists under a
strong cloud of illegitimacy.”4 In fact, they can serve as an important role in
preventing epistemically dubious information from misleading jurors. We can,
contra-Laudan, find strong and empirically well-supported support for their use in
many cases. Though, to be clear, my thesis here will not be the much stronger claim
that all exclusionary rules, especially those found at work in the US legal system, are
epistemically justified.
1. The Case Against Exclusionary Rules
To begin consider a basic argument against exclusionary rules:
P1. Truth is the primary goal of the criminal justice system
P2. If a practice or set of rules serves to interfere with or undermine the
primary goal of an institution, then the goal should be altered or that practice
or set of rules should be abolished.
P3. Exclusionary rules interfere with the primary goal of the criminal justice
system.
P4. We should not alter the primary goal (the truth seeking imperative) of
the legal system.
C. We should abolish exclusionary rules.
The argument is valid so we need to see if the premises are in fact true.
Consider the case for premise 1—that truth is the primary goal of the
criminal justice system. As we have already seen Justice Powell was inclined to see
the law as such, and this by no means was the only time that courts have asserted
Frederick Schauer, In Defense of Rule-Based Evidence Law—And Epistemology Too,” Episteme, 5.3
(2008), p. 298.
4
the importance of the truth-seeking imperative. However, we need not rely merely
on declarations from jurists to support his point. There is a moral argument that
supports premise 1. Given the profound harms that attach to criminal convictions
we must do everything we can to insure that the outcome of criminal proceedings is
correct. Perhaps we are inclined to think that justice is an equally important value
that the judiciary should be pursuing in conjunction with truth. This may be, but no
doubt we want to be certain that when we punish someone she is in fact guilty of the
crime for which she has been convicted, and when we set someone free she is in fact
innocent. We can see the paramount importance of truth even in matters of justice
if we consider cases where he judiciary gets the wrong outcome. It is no doubt a
profound injustice when we discover that an innocent person has been convicted
and served a lengthy sentence for a crime she did not commit. Of course, it is also a
serious injustice when the guilty are set free. By insisting that truth remain a central
goal of the judicial system we work to avoid injustices like these. No gains in justice
can offset the serious harms associated with such errors of fact. This is not to
suggest there is nothing controversial about premise 1, but for the time being I
believe we can see why one should find premise 1 to be, at least, initially plausible.
The case for premise 2 is fairly straightforward. If there are practices in
place within an institution that undermine that institution’s primary purpose, then
we must either act to revise those practices or should we feel particularly strong
about those practices, then we should change the institution’s primary purpose to
reflect that. So, suppose a group takes the primary purpose of heir religion that they
go out and save lost souls by conversion to their religion. If this religious group also
forbids proselytizing, then something here must give. They must decide if they are
truly committed to converting the unsaved, and if so, they must abandon their
prohibition on proselytizing. Alternatively, if upon reflection they find that the
prohibition on proselytizing is more central to their fundamental values, then they
must alter the primary purpose of their religion. At heart here we find simply a
matter of consistency.
Consider how this applies to the present context. If it is true that
exclusionary rules are at odds with the epistemic function of the legal system, then
we find—given premise 2—that we must either abandon the epistemic imperative
or we must get rid of exclusionary rules. Given what we have already said in
defense of premise 1 it seems incredibly difficult to give up the epistemic
imperative. What would it mean to abandon the truth-seeking imperative of the
criminal justice system? Would we be prepared to accept false convictions now? It
is something of truism within the legal system that it is better to let one hundred
guilty men go free than to let one innocent man go to jail. If we abandon our
commitment to the truth will we also accept that innocent people must go to prison?
All of this simply serves to corrupt a legal system. It seems best then, that if we are
faced with a choice between keeping exclusionary rules and rejecting the epistemic
imperative or keeping the epistemic imperative and rejecting exclusionary rules, the
latter is the best option available to us. Premise 4 seems to stand on solid ground.
But should we think that exclusionary rules interfere with the epistemic
function of the criminal justice system? Premise 3 is the most contentious of the
premises, and thus deserves more careful discussion than what has been said in
defense of the argument to this point. In the following two sections I consider two
different lines of support for premise 3.
2. The General Epistemic Case Against Exclusionary Rules
Ideally in a criminal case jurors will be presented with will reliable, relevant,
and comprehensive information necessary to make the decision. Efficiency
demands that this process be streamlined to some extent. The analogy between a
jury and a scientific inquiry is inexact. Ideally, in a scientific inquiry, there will be no
time limit in which the scientists must operate. They will be free to consider all
relevant alternative explanations for a given phenomenon, they can run tests to
determine if those alternatives offer a more plausible explanation. Not so with
criminal trials. Jurors’ purposes are more narrowly focused. They are not charged
with determining if a crime happened and if so, who did it. Rather, they are asked to
determine if a crime happened and if so, is there sufficient evidence to conclude that
the defendant did it. In effect they are not asked to determine who really committed
the crime. We could imagine cases in which there is strong evidence that Smith
committed a crime. Suppose that the evidence is strong enough that it satisfied the
requirement that the defendant is guilty beyond a reasonable doubt, and the jury, as
a result, convicts the defendant. All of this is consistent with the fact that there is
other even stronger evidence that suggests that it was not Smith but Jones who
committed the crime. If jurors did not consider the evidence in favor of Jones’s guilt
rather than Smith, they have done nothing wrong. Their job is to evaluate the
evidence in favor of Smith’s guilt, not Jones’s. If a scientific inquiry were conducted
in the same way we would think it had failed. We may think prosecutors and the
police have failed in some way by not pressing the case against Jones, but that is
beside the point. What we need to see here is that there are some significant ways
in which the job of the juror is different from the job of the scientist.
Still, if we hope that such cases are anomalous, then we will want insure that
jurors have access to all the reliable and relevant information. Even in this respect
the juror’s task is different from the scientists. Consider how determinations of
relevance are made in criminal justice cases. Whereas members of the scientific
community are left to decide what information is relevant, this is not the case with
jurors. Instead it is left up to the judge presiding over the case to determine if
evidence is relevant. Laudan argues that here a judge should consider if the
evidence were credible would it result in a change in probability that the crime
occurred or that the defendant committed the crime. If so, then the evidence should
be presented to the jury.5 Of course, there may be cases in which IF some evidence
were credible it would change the probability of the hypotheses that a crime
occurred or that the defendant committed it, but we still think it should not be
considered. So more must be said about this. Laudan clarifies the idea at play here
when he writes, “Any testimony or physical evidence that would make a reasonable
person either more inclined or less inclined to accept these hypothesis is relevant.
Everything else is irrelevant.”6 Suppose the prosecution wants to introduce
evidence that the shape of the defendant’s skull is such that she has a high
propensity to commit the type of crime that she is accused of committing. Of course,
5
6
Laudan, p. 17-8.
Laudan, p. 18. My emphasis.
phrenology is pseudoscience and thus should not be considered. Rather, the
hypothetical should be limited to what would lead a reasonable juror to alter her
probabilities, and phrenology should not lead a reasonable juror to alter her
probabilities. It is thus, in that respect, irrelevant.
Evidence may be relevant, but not reliable. No doubt jurors are often
presented with evidence that is relevant, but is also inconsistent. If we were to
assume all evidence were equally reliable, then it would be unlikely that any person
would found guilty. The mere presence of inconsistent, equally reliable information
may be enough to generate a reasonable doubt. We know, however, that not all
evidence is equally reliable. Jurors may doubt the exculpatory testimony of a
coconspirator or doubt the inculpatory testimony of a corrupt police officer. Thus,
issues of credibility are to be left out of the judges’ hands and in the hands of the
jurors. Essentially the judge should allow all relevant information to be presented
to the jury, and then the jury will answer questions about credibility or reliability.
Juries are charged with determining the facts of the case once they have been
presented with all the relevant information. It is the common practice of our legal
system that judges determine relevance, but jurors are the appropriate triers of fact.
It is at this point that we can see why exclusionary rules might, as a general
matter, thwart the epistemic goals of a jury trial. Exclusionary rules serve to
preclude reliable information from being presented to the jury. So rather than
having access to all the relevant information, jurors are given access to only some of
it. Perhaps it is thought that a defendant’s spouse witnessed the defendant commit
the crime. However, because of spousal privilege, the spouse can refuse testify
without having to risk perjuring himself. Further, if the judge deems some evidence
unfairly prejudicial—evidence so sensational or inflammatory that ordinary jurors
would be unduly swayed—then she can exclude that evidence. So, for example
particularly gruesome crime scene photos may be excluded for this reason. The
problem with exclusionary rules then, as a general matter is that they serve to
exclude relevant evidence. It is typically up to the jury to determine what weight
they give the presented evidence, but in some instances judges intervene for fear the
jury will improperly weigh the evidence and thus prevent the jury from hearing it. If
we are willing to trust juries with the lives of defendants—sometimes literally—
then we must also trust them to properly weigh the evidence.
The issue of unfairly prejudicial evidence raises a related worry. Laudan
worries that when judges exclude evidence because they fear it will be unfairly
prejudicial they are at best guessing as to what impact that evidence may have on a
jury.7 Without well-designed empirical studies judges are left without any objective
means of determining what evidence may or may not be unfairly prejudicial.
Without an objective means of sorting this out, the judge is doing armchair
psychology, and no doubt we may be concerned with such a procedure when it may
allow a guilty person go free or send an innocent person to jail.
We can see that exclusionary rules work to prevent the jury from hearing all
of the relevant evidence. But this violates what we take to be best epistemic
practices. Attempts to ground exclusionary rules in some more general fear about
the jury’s propensity to misunderstand the evidence seems unduly paternalistic, and
7
Laudan, p. 20-21, 121-2.
Laudan worries the restrictions are not properly grounded in solid empirical
studies.
3. The Epistemic Case Against Excluding Recanted Confessions
In some cases defendants will offer confessions to police, but later think
better of it and seek to have those confessions excluded from the trial. Once a
confession has been made it cannot simply be withdrawn. Here the burden shifts to
the defendant to show that there is some reason to think the confession was
improperly obtained.
In order for a judge to allow a confession to reach the jury the confession
must pass a three-part test. First, it must be the case that the confessions were
given voluntarily. The judge must deem that the defendant who now wishes to
plead innocent gave the confession of her own free will. Next it must be determined
that the confession was obtained legally. A familiar example where a confession
would not pass the legality test is a case in which the defendant offered her
confession without being read her Miranda rights. Of course, Miranda is not the sole
consideration. The Supreme Court has ruled that confessions obtained from
illegally detained individuals, even when they have been read their Miranda rights,
should be excluded.8 Finally, even when a judge is satisfied that the confession was
given voluntarily and obtained legally the confession must pass the test of
corroboration. Here the judge must determine if some of the prosecution’s other
evidence supports some of the claims made by the defendant about the crime in the
8
See Brown v. Illinois, 422 U.S. 590 (1975).
confession. If the confession passes these three tests then it can be included in the
trial. However, if the judge finds that the confession violates any of these three tests,
then the confession may be excluded.
If juries are to be triers of fact, then suppression of evidence in these cases
seems inexplicable. The problem with excluding confessions at all is that they are
certainly relevant evidence worth consideration by the jury. This is not to doubt
that there are false confessions, but again, this is something for the jury to sort out.
If the defense believes that there are reasons to doubt the veracity of the confession,
then this is the sort of thing that ought to be presented to jurors for consideration.
What should not happen, according to Laudan, is that the confession should be
suppressed.
Consider, however, some problems with how the three-prong test works in
practice. No doubt we should be concerned about police beating, or even
threatening to beat, detainees in order to get a confession, and it seems even Laudan
agrees that such confessions should be suppressed. Coerced confessions are
dubious for obvious reasons. Courts however have come to understand coercion
much more broadly than this. In fact, the courts have found that once an individual
is in police custody that is enough to rule that their actions are no longer sufficiently
voluntary. Of course, this makes one wonder how any confession is supposed to be
obtained legally. This is what Miranda is intended to address. Once one’s Miranda
rights have been explained, only then (with a few exceptions) will a confession be
considered uncoerced.
Laudan objects to this because we can recognize the dubious nature of
confessions obtained by torture or threats of torture, but absent that, in a case
wherein the police act reasonably, but simply forget to read the defendant her
Miranda rights, would we really think that this confession is coerced? The Supreme
Court has ruled that such a confession should be excluded. If, however, our interests
are epistemic, then it seems the confession provides some relevant evidence and the
jury should hear about it. Laudan suggests that perhaps a better method is to
simply insist that confessions be videotaped and to throw out any that are not.9
This can gives the jury evidence to evaluate for themselves whether the defendant
acted voluntarily, and whether or not the police used force to obtain the confession.
Similar worries lurk for the legality test. If police question the defendant for
too long without being presented to a judge for arraignment, or if the defendant is
denied access to an attorney, then the confession can be excluded. The problem
here, according to Laudan, is that these conditions speak to the poor behavior of the
police who do the interrogating, but they do not give us good epistemic reason to
doubt the veracity of the confession.
Finally, the corroboration test puts the judge in the position of evaluating the
reliability of the confession, and this is supposed to be the purview of the juror. We
may think that this is a valuable test in part because the jurors will likely take a
confession, even a recanted one as definitive proof of the defendant’s guilt, but
Laudan believes that we must again trust jurors to make reasonable judgments of
fact. If we are concerned seriously about this problem we may insist that the judge
9
Laudan, p. 229.
include in jury instructions that confessions are not dispositive, but we should not
exclude the confessions entirely. Laudan cites approvingly one study that found
that jurors convict 54.5% of those defendants who offer no confession, and 78.7% of
those who made a confession.10 While there is a substantial difference the
important thing to note, according to Laudan, is that “…even when the juries had a
confession in hand, they voted to acquit in almost one-quarter of the cases.”11
4. The Epistemic Case for Excluding Recanted Confessions
Perhaps questioning the epistemic value of recanted confessions seems
dubious. Indeed, if we agree that jurors should have access to all relevant
information, then surely we must think that a confession, even if recanted, is
relevant. Yet I intend to do just that—in this section I argue that we have very good
epistemic reasons, at least in some cases, to exclude recanted confessions.
It is worth focusing a moment not on the dubious nature of the three-prong
test to determine whether a recanted confession should be excluded, but instead on
the intuitive case for including recanted confessions. We are inclined to think this is
relevant in part because it seems highly implausible that one would offer a
confession for any other reason than that one is guilty. On this very point Laudan
writes:
Is it plausible that an innocent suspect, subjected to neither torture nor the
threat of it, offered no particular incentives to confess, and threated
reasonably humanely by arresting officers, is likely to tender a false
Richard A. Leo and Richard J. Ofshe, The consequences of False confessions: Deprivations of Liberty
and Miscarriages of Justice in the age of Psychological Interrogation, 88 Criminal Law & Criminology
429 (1998)
11 Laudan, p. 180
10
confession simply to get himself out of the interrogation room and into a jail
cell? The question answers itself. Innocent people, even when subjected to
the humiliation of an arrest, do not routinely confess to crimes they did not
commit, especially since they fear, understandably enough, that such
confessions may mean several years in prison. (175)
It is this belief that innocent people do not confess that makes confessions such
powerful testimony. We take it as given that with such high stakes almost no one
would possibly admit to such a thing. Unfortunately, this does not appear to be the
case. As a matter of fact a great number of people confess to crimes they did not
commit.
For example, Billy Gene Davis confessed to killing his girlfriend after failing
two polygraph tests. His girlfriend was later found alive in Tucson, Arizona.12 In
another case Daniel Williams, after 11 hours of grueling interrogation confessed to
raping and murdering a neighbor, Michelle Bosko. The police soon discovered that
Williams’ account of the murder did not fit the details of the autopsy report. They
secured a new confession; one in which the details of the confession better fit the
details of the crime. When DNA tests were returned from the autopsy it was
discovered that the semen found in the victim was not Williams’s. The police
decided that Williams must have had an accomplice, so they secured a third
confession in which Williams implicated his roommate, Joseph Dick (though no
previous confession had mentioned anything about there being an accomplice).
After a lengthy interrogation, Dick too confessed to the crime. Soon thereafter it
was found that neither of the two men was the source of the semen. Deciding that
there must have been even more accomplices—though none of the other evidence
12
Leo and Ofshe, p. 449-50.
suggested that the attack involved so many individuals—the police secured yet
another confession from Williams and Dick in which the both implicated two more
men. The two other men eventually confessed to the crime as well. Eventually
another man came forward and confessed to the crime and told police he had acted
alone, and in this case the DNA was a match. Three of the four men who confessed
spent eleven years in prison and one spent eight.13 In yet another case police were
able to obtain confessions from Ruben Trujilo and Pedro Delvillar for a double
murder and robbery. It was later determined that both were in police custody at the
time that the crime occurred.14
According the Innocence Project about 30% of DNA exonerations involve
defendants who made incriminating statements, confessed to the crime, or pled
guilty.15 District Judge Jed S. Rakoff conservative estimates suggest that as many as
20,000 people in prison today are there because they have pled guilty despite the
fact that they are innocent.16
Social scientists believe that confessions represent particularly powerful and
compelling evidence at trial—even when that evidence is highly suspect. In fact,
even when there is evidence that confessions are suspect they remain highly
influential. In one study 132 judges were presented with hypothetical cases in
which there was weak evidence to support convictions, but in some of those cases
David A. Harris. Failed Evidence: Why Law Enforcement Resists Science. (New York: New York
University Press) 38-9.
14 Leo & Ofshe, p. 450.
15 The Innocence Project, Understanding the Causes: False Confessions.
http://www.innocenceproject.org/understand/False-Confessions.php
16 Indeed the number may be much higher. Social scientists argue that 2-8% of the 2.2 million people
in prison have accepted plea bargains despite the fact that they are innocent. Rakoff’s numbers are
based on a more modest estimate of 1%. See Jed. S. Rakoff, Why Innocent People Plead Guilty, The
New York Review of Books, November 20, 2014.
13
there was no confession, in some there was a confession produced with little police
pressure, and finally in some confessions came as a result of high-pressure. In the
high-pressure cases the defendants were questioned for 15 hours, the defendants
were threatened with the death penalty, a gun was waved, and the interrogators
refused to consider the defendant’s claims of innocence. In 84% of the cases the
judges thought that the high-pressure confessions were not voluntary, but in spite of
this and in spite of the fact that other evidence to support the charge was weak
there was a 69% conviction rate among the judges in the high pressure/ weak
evidence cases. Yet in the no confession/weak evidence cases there was only a 17%
conviction rate.17 What we find is that even among professional jurists, and even
when there is significant doubt about the voluntariness of the confession, the
confession plays a substantial role in convictions. This is particularly relevant to
Laudan’s concerns about prejudicial evidence because he fears that judges are
playing the role of armchair psychologists when they exclude evidence for this
reason. As it turns out, psychologists are gathering useful information about these
things and the evidence supports the claim that people tend to over estimate the
value of confessions.
In part the impact of confessions is likely explained by the deep-seated belief
that many share with Laudan that innocent people do not confess to crimes that
they did not commit. In one study 91.3 percent of the participants thought that they
would not confess to a crime they did not commit when questioned by police. When
the crime involved a serious offense like rape or murder the number rose to 93.3
17
Saul M. Kassin, “Why Confessions Trump Innocence,” American Psychologist (67.6) (2012): 434.
percent.18 So what can explain the fact that many do confess to crimes they do not
commit?
We may think that much of this is explained by acts or threats of violence,
but the matter turns out to be much more complicated. Often investigators will
attempt to convince the accused that claims of innocence are pointless—they will in
effect ignore any claims of innocence—and instead seek to convince the accused
that protesting their innocence is pointless. Police will often tell the accused that
they possess some bit of incontrovertible evidence that proves beyond a doubt that
the accused is guilty, even if no such evidence exists. The accused are told that there
is forensic evidence—such as DNA—that proves their guilt, that fingerprints or
other evidence has been found, someone else has implicated them, or that a
polygraph has shown their claims of innocence are false.19 Police may say this even
if none of it is true; the Supreme Court has ruled that police may mislead suspects
during interrogations.20 In conjunction with this there is also a two-part strategy of
using maximization and minimization. In maximization the accused is told what
severe consequences may follow if the accused continues to insist on her innocence.
She may, should she fail to “come clean,” face long sentences or even the death
penalty. This strategy is combined with minimization where the interrogator offers
a potential justification or mitigating circumstance to help justify why the accused
did what she is accused of. Perhaps she was acting out of self-defense, the victim
Mark Costanzo, Netta Shaked-Schroer, and Katherine Vinson, Juror Beliefs About Police
Interrogations, False Confessions, and Expert Testimony,” Journal of Empirical Legal Studies (2010):
238.
19 Harris, p. 44-45.
20 Frazier v. Cupp, 393 U.S. 732 (1969).
18
had it coming, or the accused was drunk or mentally impaired.21 All of this produces
a powerful incentive for the accused to confess, regardless of her guilt of innocence.
This is a rough and basic outline of what is called the Reid Technique of
interrogation, a method adopted by the police, the F.B.I., the C.I.A., and the Secret
Service.22 All of this then is consistent with standard practices. What is
disconcerting about this is that despite Laudan’s concerns that the prong-test is
needlessly restrictive, it appears it is not restrictive enough. Since Reid Technique
confessions are thought to be susceptible to false confessions, yet this process is
within bounds with respect to the three-prong test.
In addition to this there is some data that confessions serve to skew the
interpretation of other evidence. In one study fingerprint experts were given a set
of prints from previous cases that they had correctly evaluated. When they were
presented the fingerprints the second time in some cases they were provided no
extraneous information, in some cases they were told the suspect had confessed
(suggesting a match), and finally in some cases they were told the suspect was in
custody at the time of the crime (suggesting the prints would not match). In the two
cases in which guilt or innocence was suggested there was a 17% change from the
original, correct decision.23 In yet another study a theft was staged and witnesses
were asked to help identify the culprit. The photos the witnesses were shown did
not contain the perpetrator. Later the witnesses were told that the person they
identified denied guilt, had confessed, or another person in the photo array
Harris, p. 45.
Douglas Starr, “The Interview: Do Police Interrogation Techniques Produce False Confessions?”
The New Yorker, December 9, 2013.
23 Kassim, p. 434.
21
22
confessed. 61% of those told another person confessed changed their identification
and were confident in their new identification. 50% of the witnesses who had not
made an identification, after being fed misleading information, identified the
confessor as the person they saw commit the crime.24
So the epistemic situation now seems worse. Not only may the confessions
themselves be dubious, but the confessions may serve to bias other evidence as well.
Further, we see that confessions are psychologically compelling even among
experienced judges. Given that it seems judges are likely to take even dubious
confessions very seriously it seems fair to infer that jurors would do the same.
Especially since most think that they would never confess to a crime they did not
commit. Because this evidence can be so powerful I believe exclusionary rules in
this case can be truth promoting.
Excluding recanted testimony, perhaps in cases in which there is fear that the
confession was obtained dubiously seems consistent with the best practices of an
epistemic enterprise. Suppose you are conducting a very important experiment, one
in which the stakes are quite high. Suppose also that I offer to give you a piece of
evidence that would be relevant to your research. This evidence comes with a
caveat. First, the evidence has been collected in a dubious manner that has a
propensity to produce false positives. That’s not to say all the results of this method
are wrong, but that the propensity for false positives have led members of the
scientific community to doubt that technique used to gather information in this way.
Second, evidence of this sort tends to be extraordinarily compelling. That is, when
24
Kassim, p. 437.
people are provided with positive results from this test they are often treated as
dispositive, even when people know that the information is error prone. If I were to
ask you if you wanted this information, then I would think that the epistemically
correct answer is: no. Given that we do have information that suggests recanted
confessions are highly influential, and given the serious doubts about how this
information is collected, the epistemically correct thing to do is to exclude the
evidence from consideration.
One may wonder if my skepticism runs so deep that I believe all confessions
are epistemically worthless. This is not the case. As a matter of fact many of the
cases of genuine false confession that we know about came to light because the
actual perpetrator came forward and confessed. Laudan himself argues that all
confessions should be videotaped25, and indeed this tends to reduce false
confessions, but this does not go far enough. The more serious concern here centers
on the Reid Technique itself, and it is by no means clear that jurors would know that
this method of interrogation has a propensity to produce false confessions. It would
be much better if there were better standards used in interrogations themselves.
Police need to be educated about the dangers of confirmation bias, and taught to test
for indicators that the confession is false. For example, one very simple technique is
to ask the confessor to detail the events of the crime in reverse order. Recounting
events of one’s life in reverse order is often very easy to do if one is telling the truth,
however when one is lying, and trying to keep manufactured details straight in one’s
mind, recounting them in reverse order proves extraordinarily difficult. The upshot
25
Laudan, p. 229.
of using such techniques is that it can also flag false declarations of innocence.
Social scientists are producing very interesting information about these matters.
They need to be incorporated into the best practices of more police agencies.
5. The General Epistemic Case in Favor of Exclusionary Rules
I have argued that we have epistemic reasons to exclude some recanted
confessions from consideration by jurors. This argument may not generalize. As a
matter of fact I think that in many instances Laudan is correct that exclusionary
rules as they operate in the US legal system are confused and inexplicable. Oddly
enough illegally obtained evidence may be used in some circumstances and not
others. If the police conduct an illegal search of White’s home and find the ledger in
which he keep meticulous records of who sells meth for him and how much they
sell, then the police may not use that evidence against White. The police may use
that illegally obtained evidence against the people found in White’s ledger, and this
is because their Fourth Amendment rights were not violated.26 We may think that if
the evidence is collected illegally, then it should be excluded, or alternatively if it
may be used, then it may be used against everyone it implicates. But obviously the
Courts disagree. Further, we may wonder why only defendants can appeal
convictions, but prosecutors cannot appeal when the jury finds the defendant not
guilty.
I do argue, however, that exclusionary rules can and should play an
important epistemic function. In fact, I think the case can be made that all questions
26
This is a revised example of one offered by Laudan, p. 186.
of reliability are not left up to the jury and this is as it should be. Remember that
judges really don’t allow any possibly relevant information to be presented to the
jury. Rather, they only allow evidence that would lead a rational individual to alter
their probabilities about whether the crime occurred and whether the defendant
committed the crime. Thus, we exclude phrenology from consideration because it is
a pseudoscience. But it seems plausible that really what we are saying is that
reasonable people should not find this evidence reliable. It is relevant on some
standard—the expert phrenologist tells us that the shape of the accused’s skull
speaks towards her propensity to commit the given crime, but we ignore this
evidence not because it doesn’t speak to the accused’s guilt, it does, but rather we
exclude this because it is unreliable.
Epistemically there is nothing dubious about doing something like this. If a
scientist ignores an improperly conducted study from consideration she does not
violate any epistemic norms, rather she satisfies them. So too with a judge who
excludes epistemically dubious evidence from the jury. Thus, when a judge excludes
an epistemically dubious confession from consideration by the jury this does not
undermine the epistemic purpose of the jury. Laudan may object that common law
practices don’t operate like this. Again it has been traditionally the role of the jury
to make determinations of fact.27 What remains unclear is why this is epistemically
justified. We may typically think that crime scene evidence is relevant information
that the jury should consider. If however, it is quite clear that the evidence
This is not entirely correct. Judges are asked to make judgments about both the relevance and the
reliability of expert witnesses. This is how it should be. We should work to insure that judges
consider excluding more forensic ‘science’ because of its unreliability. See Daubert v. Merrell Dow
Parmaceuticals, Inc. 509 U.S. 579 (1993).
27
gathering process was highly corrupted, then it is not clear that the judge subverts
the epistemic goals of a jury trial by excluding this evidence from consideration by a
jury. Indeed, such evidence should sway no rational person.
To get to the heart of the matter I think that Laudan misdirects his epistemic
concerns. Even if we must radically rethink how we employ exclusionary rules, this
does not mean that exclusionary rules are epistemically corrupting as such. The
more serious epistemic concerns that we should have are with the evidence
gathering process itself. There is mounting evidence that much of what counts as
forensic science is no science at all. Until we clean up the work of forensic science
there is still an important role for exclusionary rules to play.
Consider the practice of fingerprint analysis. The standard practice for
analyzing fingerprints uses a process known as ACE-V: Analyze, Compare, Evaluate,
Verify. What this means is that a fingerprint analyst is given a set of fingerprints and
asked evaluate if there is a match between the suspect and the prints found at the
scene. In the analysis phase the analyst fist examines the quality and quantity of
loops and ridges to determine if there is enough evidence to make a match. If there
is enough detail in the found print and the sample taken from the suspect then a
comparison is made. Here the analyst determines if there are sufficient similarities
to determine whether the two sets of prints correspond to each other. If they do,
then, in the evaluation phase, the analyst makes a determination that the points of
correspondence are sufficiently similar to match the set of prints. At this point the
analyst then renders a judgment: the prints match, an exclusion (there is substantial
disagreement between the two sets of prints), or inconclusive. In the final stage,
verification another analyst repeats the process of analysis, comparison, and
evaluation.28
Two problems stand out with this process. First, a declaration of a match is
taken to be declaration that the unknown print has, with 100 percent degree
certainty, come from accused. The problem however is that there are no established
standards for declaring a match. The determination is a subjective judgment. As
David Harris states in his book Failed Evidence, “This judgment comes not from
comparisons of data that would ground the probabilistic judgment in statistics, as it
should, but form the judgment of the human being making the comparison.”29 Thus,
despite common belief that fingerprint analysis relies on hard science, it is much
more subjective than that. Second, the verification process is not conducted blind.
The second analyst is often made aware of determination made by the first analyst.
This, of course, subverts the scientific validity of the process. The problems with
nonblind testing are well known, and thus we must fear that verification process is
often biased by the initial findings.
Similar problems exist with eyewitness identification. Often eyewitnesses
are given a photo array in which they are given a sheet with the pictures of six
individuals and asked if the suspect is among those pictures. Studies show that this
process leads to errors. The problem arises from the fact that when given photos
concurrently the witnesses tend to make a comparative judgment about which of
the six looks most like the perpetrator. Unfortunately, comparative judgments lead
See Harris 24-26. See also Jennifer L. Mnookin, “Of Black Boxes, Instruments, and Experts: Testing
the Validity of Forensic Science,” Episteme 5.3 (2008): 343-58.
29 Harris, p. 27.
28
to inaccuracies. The question is not which of the six looks most like the perpetrator
the question is whether or not the perpetrator is found among the six pictures. This
can be mitigated by consecutively showing witnesses single photos. In this case the
witness is simply comparing her memory of the perpetrator with each photo. The
change is subtle but produces substantial improvements. Despite this fact many
police agencies have been slow to adopt this new technique. Problems also occur
here because the line-ups and photo identifications are also not conducted blindly,
but instead by officers or investigators who know who the prime suspect is in the
case. They may often, even if unintentionally, provide cues to the witness about
whom to select.30
This is by no means a comprehensive account of the questionable practices
involved in contemporary forensic science. It is in this way that I believe that
Laudan’s efforts are misdirected. Exclusionary rules should not be the source of our
primary concern with the legal system, at least when our concerns are epistemic. As
it turns out juries are often presented with evidence that is questionable, yet it is
often presented as being scientifically sound. Again, if we were to rely on the
scientist as the paradigm of sound epistemic practices, we would have no problem if
she ignored or excluded evidence that was not obtained using the best the practices
of modern science. If we hope to improve the jury’s ability to make epistemically
reliable judgments we would do more to insist on improved forensic science than to
demand that exclusionary rules be abolished or significantly limited. If anything,
until the forensic practices of police improve, there is a case to be made for an
Harris, 47-55. See also Elizabeth F. Loftus, Eyewitness Testimony. Cambridge: Harvard University
Press, (1996).
30
expanded role of exclusionary rules within the legal system. Judges should exclude
more of the epistemically questionable evidence that is often presented as being
grounded in hard science, when it is, in fact, not.
Conclusion
There is much to be said for Larry Laudan’s objections to exclusionary rules,
and indeed he makes a compelling case that many of the present exclusionary rules
as they operate in the US legal system are questionable, at least on epistemic
grounds. However, I have argued here that we can defend some of those rules as
serving an important epistemic function. As we have seen confessions, even those
given under questionable circumstances, can have a powerful impact on those
rendering legal judgments. Given that many may be inclined to treat confessions as
dispositive, there is a strong case to be made that in some cases excluding recanted
confessions will allow the jury or judges to evaluate the evidence in light of the
remaining, hopefully more reliable evidence.
Further, I believe as a more practical matter exclusionary rules can play an
important epistemic role in the legal process. It is consistent with the best practices
of science to exclude or ignore unreliably gathered evidence, and once we
acknowledge that, we see there is an important role for exclusionary rules to play.
Exclusionary rules do not always subvert epistemic processes; they can sometimes
play an important role. Thus, even if we find many of our current exclusionary rules
to be suspect, that does not mean they should be done away with. Rather, we should
consider revising the old, more dubious rules, and consider a new role that they may
play in improving the epistemic outcomes of trials. Thus, premise 3, the claim that
exclusionary rules interfere with the primary role of the legal system, is false.
In closing it would be wrong not to lodge at least some complaint against
premise 1— that truth is the primary goal of the criminal justice system. Laudan’s
interest is on the epistemic reliability of jury trials and the criminal justice system
more broadly, but surely even if truth is the primary goal of the criminal justice
system we should see that we have political and moral goals that should constrain
that process. While excluding illegally obtained evidence may strike us as
epistemically unjustified, we may still wish to exclude illegally obtained evidence for
political reasons. Laudan argues that this rewards the guilty, and fails to punish the
offending police officers.31 One possibility Laudan suggests is to allow the criminal
to sue the offending police officers in civil court. As a practical matter I have my
doubts that this will serve to curtail police misconduct. Convicted criminals have
limited access to attorneys as it is, and it is unlikely that from prison they will be
able to afford or recruit attorneys willing to take their cases. Further, we may worry
that juries will be unlikely to reward convicted felons for damages (would damages
include the time they spend in prison?). Excluding illegally obtained evidence gives
police strong incentive to conduct their investigations according to the letter of the
law. And one might imagine that if a police officer consistently has evidence thrown
out, that this will result in professional penalties. Laudan wonders why we exclude
evidence from relatively innocuous acts done by police.32 I am inclined to think that
31
32
Laudan, p. 225.
Laudan, p. 186.
searches by police are always serious and we should treat the claim that some of
them can be innocuous as dubious.