The Dangerous Unreliability of Eyewitnesses
Summary
TLDRThe video script discusses the crucial role of eyewitness testimony in wrongful convictions and the scientific research behind improving identification accuracy. It highlights reforms in police procedures, such as warning witnesses that a suspect may not be present in lineups, and ensuring the administrator is unaware of the suspect. The script also critiques forensic techniques like fingerprint and bullet analysis, emphasizing the lack of scientific validation compared to DNA testing. The National Academy of Science urges a reevaluation of traditional forensic methods to ensure accuracy in criminal investigations.
Takeaways
- đ§ Eyewitness testimony is the leading cause of wrongful convictions, despite extensive psychological research on its unreliability.
- đŹ Over 30 years of research by experimental psychologists have explored how different techniques for photo arrays and lineups impact the accuracy of identifications.
- đ Simply warning a witness that the perpetrator may not be in a lineup can significantly reduce incorrect identifications without affecting accurate ones.
- đ Double-blind procedures, where the administrator doesn't know the suspect, prevent bias and the influence of confirming feedback on witnesses.
- đ Confirming feedback, like praising a witness for their choice, can falsely increase their certainty and belief in their identification accuracy.
- âïž Legal tests used to determine the reliability of witness identifications, such as certainty and attention, are misaligned with scientific evidence.
- đ A National Academy of Science report on forensic science stated that DNA testing is the only fully validated forensic method.
- 𧩠Pattern evidence such as fingerprints, tire tracks, and bullet striations lacks sufficient validation and statistical backing for reliability in court.
- â Claims that a bullet or fingerprint uniquely matches a suspectâs gun or print to the exclusion of all others are scientifically unfounded.
- đ The scientific community is urged to re-evaluate and research forensic pattern evidence to establish a more robust and reliable basis for use in court.
Q & A
What is considered the single greatest cause of wrongful convictions?
-Eyewitness testimony is considered the single greatest cause of the conviction of innocent people.
What has experimental psychology research shown about eyewitness identification?
-Research has shown that certain techniques, such as how photo arrays and lineups are conducted, can either improve the accuracy of identifications or lead to errors. The research highlights ways to enhance reliable identifications and reduce mistakes.
What is the significance of warning a witness that the perpetrator may or may not be in a lineup or photo array?
-Giving this warning significantly reduces incorrect identifications without lowering the number of correct identifications. It helps prevent witnesses from guessing.
Why should the person administering a lineup or photo array be 'double-blinded'?
-The administrator should not know who the suspect is to avoid influencing the witness, either intentionally or unintentionally. This prevents bias or feedback that could falsely inflate the witnessâs certainty.
What is the effect of giving confirming feedback to a witness after identification?
-Confirming feedback, such as telling a witness they made a correct identification, can falsely inflate their confidence in their choice and their belief that they had a good opportunity to observe the crime.
How does confirming feedback affect legal tests for eyewitness reliability?
-Confirming feedback can distort factors like certainty, opportunity to observe, and attention, which are traditionally used by courts to evaluate eyewitness reliability, making these legal tests misaligned with scientific evidence.
What does the National Academy of Science report say about forensic sciences?
-The report states that DNA testing is the only fully validated forensic discipline. Other pattern-based evidence, like fingerprints and bullet striations, lacks sufficient scientific validation.
What are the concerns with pattern-based forensic evidence like fingerprints and bullet striations?
-Pattern-based evidence, such as fingerprints or bullet striations, often lacks a proper scientific foundation, including databases and statistical measures, to support claims of uniqueness or identification.
Why is DNA testing considered more reliable than other forensic disciplines?
-DNA testing provides a statistical basis, offering frequency estimates for specific DNA profiles in different populations, unlike other forensic methods that often rely on subjective interpretations without statistical backing.
What did the National Academy of Science recommend for forensic disciplines besides DNA testing?
-The Academy recommended that forensic disciplines like fingerprint analysis and bullet striation matching undergo more basic research to establish scientific validity and develop objective metrics for their findings.
Outlines
đ Eyewitness Testimony and Its Flaws
Eyewitness testimony is a leading cause of wrongful convictions. Research over the past 30 years has shown that certain techniques used in photo arrays and lineups are linked to more accurate identifications, while others lead to mistakes. For instance, warning witnesses that the real perpetrator might not be present significantly reduces incorrect identifications without affecting correct ones. Double-blind lineups, where the administrator doesnât know who the suspect is, also reduce the influence of confirming feedback, which can artificially increase a witnessâs confidence in their identification. Courts, however, still rely on outdated methods to assess the reliability of these identifications.
đŹ The Need for Scientific Validation in Forensic Evidence
The National Academy of Science has criticized the lack of scientific validation in many forensic disciplines, such as bullet and fingerprint analysis. Unlike DNA testing, which provides measurable statistical data, forensic experts have historically made exaggerated claims about the uniqueness of evidence like bullet striations or partial fingerprints. These claims lack a solid scientific foundation, as they do not account for the frequency of pattern similarities or offer statistical data. The report calls for more rigorous research to validate these methods and prevent the misuse of unreliable forensic techniques in court.
Mindmap
Keywords
đĄEyewitness testimony
đĄPhoto array
đĄLineup
đĄDouble-blind procedure
đĄConfirming feedback
đĄMeta-analysis
đĄPattern evidence
đĄStriations on bullets
đĄForensic science
đĄDNA testing
Highlights
Eyewitness testimony is the single greatest cause of wrongful convictions.
Over 30 years of research by experimental psychologists have improved our understanding of what makes identifications accurate or prone to error.
Telling a witness that the perpetrator may or may not be in the lineup significantly reduces false identifications.
This warning reduces incorrect identifications without significantly affecting correct ones.
Double-blind administration of lineups, where the administrator does not know the suspect, helps prevent bias.
Feedback like 'good job' after a witness selects someone from a lineup can falsely inflate their confidence in their identification.
The legal system often uses factors like certainty and opportunity to observe to assess the reliability of eyewitness testimony, which research shows can be unreliable.
Scientific studies show that suggestive procedures can artificially inflate witness confidence in their identification.
The National Academy of Science issued a landmark report criticizing the lack of scientific validation in many forensic sciences.
DNA testing is the only forensic discipline with established scientific validation.
Pattern evidence disciplines, such as fingerprint and ballistic analysis, lack proper scientific validation according to the National Academy of Science.
Experts often claim that bullets or fingerprints 'uniquely' match a suspectâs weapon or prints, but this lacks statistical backing.
Forensic analysts often provide conclusions like 'to the exclusion of all other guns in the universe,' which are not scientifically defensible.
There is a lack of databases and statistical analysis in forensic disciplines like ballistic matching and fingerprint analysis.
Even with fingerprints, partial prints at crime scenes make it difficult to scientifically claim a unique match to an individual.
Transcripts
eyewitness testimony uh of course is the
single greatest cause of the conviction
of the innocent and what's fascinating
about that is that U we have now um 30
years more than 30 years of fantastic
research from experimental psychologists
who have uh you know recreated crime
scene recreated uh events and uh played
around with which different
way we do a photo array or a lineup and
different techniques that are used
correlate more with accurate and
reliable identifications and which uh
techniques lead to errors and uh a
number of reforms have been uh uh uh
adopted uh by federal uh commissions and
uh American Bar Association the
International Association of chiefs of
police lots of policing entities based
on really good scientific research
I mean a lot of This research there's
meta analyses uh that's where you pull
together lots of different studies um
and you have a lot of confidence that
certain things uh uh are real effects
and I'll give you some examples uh that
may surprise people um for example
before you show somebody a photo array
or a live lineup you should tell the
witness um we're now going to show you
some pictures or people uh please keep
in in mind that the real perpetrator may
or may not be in this photo array or
lineup and if you don't make an
identification don't worry the
investigation will continue just giving
that warning uh dramatically reduces
incorrect
identifications Without Really reducing
correct identifications and that's of
extraordinary importance obviously in
terms of being able to go out find the
real perpetrator and not arrest the
wrong person uh there's lots of reasons
we think that this warning will reduce
eror uh certainly it inhibits people
from guessing and uh uh there's kind of
a natural inclination to do that um
another reform that's of really critical
importance is that the person that
administers the lineup of the photo
array should be double blinded that is
to say that the person should not know
who uh the suspect
is um uh and that's important for many
reasons uh not the least of which is the
possibility of
uh
feedback um confirming feedback what
again meta analyses have shown is that
if you uh say to somebody ah you pick
that number to good or give some kind of
confirming feedback whether you're a law
enforcement person or somebody else
frankly what this does is it can falsely
infl plate the person's certainty that
they made the correct identification the
witness's belief that they had a good
opportunity to observe the witness's
belief that they were paying
attention when the crime was committed
um all of these factors by the way
certainty opportunity to observe paying
attention are all factors that the
courts used to be using or use frankly
in trying to weigh the reli ability of
identification when we know that let's
say some suggestive procedure has been
used so posi uh uh confirming feedback
or even just the use of an unduly
suggested procedure can falsely inflate
these so-called reliability factors uh
uh certainty opportunity to observe
attention paid and uh the legal tests
are out of whack um with what the
scientific evidence
shows more than a year ago now the
National Academy of Science came out
with a report about forensic science
generally extremely important report a
landmark report that anybody really
interested in this field should look at
um and this report uh basically said
look DNA testing is the only validated
uh forensic discipline we have um and in
particular when you look at pattern
evidence and by this they were talking
about fingerprints and tire tracks and
looking at cations on bullets and trying
to deter excuse me whether they came
from a gun particular gun or not um all
these pattern
disciplines had not been adequately
validated uh because you would have uh
uh uh experts coming into court and they
say I'm looking at the striations of
this bullet that we recovered from the
crime scene and now I found this
defendant's gun and I fired a bullet
from that and I'm looking at the two of
them under a microscope and I see all
these lines and I think there's quote
unquote sufficient agreement and by that
and if I'm really a big quality
assurance lab I'll bring my buddy in and
he'll look at the microscope and he'll
say I think there's also agreement here
and from this I can now tell you that
this bullet came from that gun to the
exclusion of all other guns in the
universe well think about it
scientifically on what basis do you have
a database can you tell us anything
about the frequency of finding similar
patterns if indeed you have similar
patterns do you have measurement area
here can you give us a number you know
with DNA testing we can give you a
number we can give you the frequency of
a particular DNA profile in uh various
different populations can you give us a
statistic um and the answer is no they
weren't giving statistics as a matter of
fact they were just saying it's Unique
this bullet comes from that gun to the
exclusion of all guns in the universe
this is nonsense and the National
Academy of Science said so and say you
guys have really got to go back to the
drawing board and do some basic research
uh to find out what the answers are to
that question even
fingerprints um which we know when if
you take all 10 uh prints and you scan
it in and you put it into a data the
database of known uh fingerprints you
can do a pretty good job of identifying
somebody but that's not the question
when you're talking about a small latent
print at a crime scene you get a partial
thumb print let's say and every time you
lay down a print it's always a little
bit uneven and then you compare it to
somebody else's thumb print can you say
that this small latent uniquely comes
from that individual well uh that is the
way the testimony was going in for years
and it was uh uh uh without scientific
basis to say that it uniquely was this
person's print you can't say that
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