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Monday, April 25, 2005

The purpose of the Detail is to help keep you informed of the current state of affairs in the latent print community, to provide an avenue to circulate original fingerprint-related articles, and to announce important events as they happen in our field.

Breaking NEWz you can UzE...
compiled by Jon Stimac

The CSI Effect US NEWS.COM - April 25, 2005 ...on TV, it's all slam-dunk evidence and quick convictions. Now juries expect the same thing--and that's a big problem...

Patient Process of Fingerprinting Yields Rich Rewards of Evidence AUBURN JOURNAL, CA - April 24, 2005 ...fingerprints left behind at the scene of a crime could lead investigators right to the culprit who inadvertently left them there...

Wendy's Recovering from Finger Hoax   NEW YORK TIMES, NY - April 23, 2005 ...the 'victim' has since been arrested, and police believe the incident was a hoax....

Does the FBI Have Your Fingerprints?   SLATE  - April 22, 2005  ...perhaps, if your one of the following: criminal, suspected criminal, government employee, military personnel, and a few others...

Last week, we took a look at the Human Identification 2005 e-symposium from the week before.  The fingerprint related presentations are now archived and can be listened to at any time by visiting the website, registering, and accessing them at your leisure:

This week we look at the publication of recent information regarding the fundamental difference between experts and non-experts by Dr. Tom Busey of Indiana University and John Vanderkolk, Indiana State Police.

Fingerprint study offers clues to how expert minds

By Bethany Nolan, H-T Staff Writer

April 18, 2005

They’re the staple of every television crime show — the earnest expert who testifies the suspect’s fingerprints match those found at the scene.

While such experts exist in real life, do they really know more about fingerprints than the rest of us?

Yes, says Tom Busey, an associate professor of psychology and cognitive science at Indiana University.

Busey and John Vanderkolk — a veteran fingerprint examiner and laboratory manager for the Indiana State Police at Fort Wayne — have completed a study that shows experts’ brains work differently than those of non-experts when confronted with two prints to examine.

Vanderkolk said the idea for such a study came to him after he learned of a federal judge who’d ordered a prosecutor to show the fingerprints gathered in a case to the jury, and let them decide whether the prints proved the suspect was at the scene.

While the judge later reversed his decision, Vanderkolk was searching for some way to prove experts are truly experts. “Then, we had no ammunition to show we’re different,” he said. “Now we do.”

He contacted Indiana University, and began working with Busey.

In the study, Busey first “listened in” to the brains of both experts and nonexperts as they looked at images.

That process involved a cap that looks a bit like something out of a science fiction novel — a tight-fitting cloth headpiece wired for sound with dozens of small multi-colored receptors.

Participants sat in a large recliner in a tiny room deep in the heart of the psychology building, looking at images on a computer screen as their brains sent out data.

The headpiece allowed him to “hear” neurons firing in the brain, producing a pattern that could be studied, Busey explained.

That data was contrasted against other data showing how people recognize human faces.

That practice, called configural processing, involves relating parts of an image to each other. For example, people seeing a human face generally process it configurally — meaning they see it as a whole, rather than eyes, nose and mouth once at a time.

That’s how fingerprint experts see the prints they’re examining, especially when comparing one to another and especially if those prints are surrounded by “noise” — dust, dirt or other smudges that might be found at a crime scene, Busey said.

“Experts were better overall,” he said. “They seemed to have superior visual memories to do particularly well with prints embedded in noise.”

Non-experts — or novices — were affected by longer delays between seeing the two prints they were comparing and showed no evidence of configural processing.

The study’s findings were published in the February edition of the journal Vision Research.

Vanderkolk and Busey have also presented their findings throughout the world, at scientific seminars and similar gatherings.  Now, they’re hoping their findings will have larger implications in courtrooms
across the nation.

They believe prosecutors and attorneys will use their findings to reinforce the admissibility of fingerprints used as evidence in court proceedings.

Fingerprints are one of several forensic methods that are often questioned in court through what’s called a Daubert hearing — so called after the 1993 civil case Daubert v. Merrell Down Pharmaceuticals.

The hearing is, in effect, a mini-trial within a trial, conducted before the judge over the validity and admissibility of expert opinion testimony.

“Our hope is to now take these findings and, at a Daubert hearing, say we think experts … should be allowed to testify,” Busey said.

ehavioral and electrophysiological evidence for configural processing in fingerprint experts

Abstract from
The Journal: Vision Research
Volume 45, Issue 4, Pages 397-525 (February 2005)

Visual expertise in fingerprint examiners was addressed in one behavioral and one electrophysiological experiment. In an X-AB matching task with fingerprint fragments, experts demonstrated better overall performance, immunity to longer delays, and evidence of configural processing when fragments were presented in noise. Novices were affected by longer delays and showed no evidence of configural processing. In Experiment 2, upright and inverted faces and fingerprints were shown to experts and novices. The N170 EEG component was reliably delayed over the right parietal/temporal regions when faces were inverted, replicating an effect that in the literature has been interpreted as a signature of configural processing. The inverted fingerprints showed a similar delay of the N170 over the right parietal/temporal region, but only in experts, providing converging evidence for configural processing when experts view fingerprints. Together the results of both experiments point to the role configural processing in the development of visual expertise, possibly supported by idiosyncratic relational information among fingerprint features.

Synopsis from Dr. Busey's web page:

How do forensic scientists make fingerprint identifications?

Fingerprints contain remarkable structure. The dynamics of the development of prints in utero dictate that ridges maintain a similar separation. This provides the kind of regularity that could enable perceptual learning processes to develop and improve the extraction of features from prints.

To address this question, we designed an experiment that extracted out what we thought were the essential elements of an identification. We tested both experts and novices. We first created pairs of print fragments:

We then presented one fragment for subjects to view for about 1 second and then showed a mask for either 200 milliseconds or 5 seconds. Then we tested the observer with two choices and asked them to pick the one they saw original. Here is a diagram of the sequence of events:

Fingerprints are often corrupted by visual noise and sometimes only part of a print is visible. To simulate these effects, we sometimes added visual noise or partially masked the fragments at test. Here are examples of these manipulations:

What we found

The basic question we're asking is whether experts before better than novices, and if so, under what conditions. The bottom line is that experts performed better than novices is all conditions, and perform especially well when full fragments are embedded in noise. We were able to tie this to a particular brain process called configural processing, and we use a brain recording technique called electroencephalography (EEG) to identify this particular mechanism. We relied on a known component of the EEG signal called the N170, and the fact that it is delayed when a face (known to be processed configurally) is inverted. The inversion disrupts the configural process, causing the delay in the N170.

It turns out that fingerprints have an orientation, and that fingerprint experts almost always view fingerprints in an upright orientation. In fact, they will sometimes invert a particularly difficult print in order to gain perspective on the pattern.

To test to see whether configural processing was active when fingerprint experts viewed upright fingerprints, we showed upright and inverted fingerprints to novices and experts. We also showed upright and inverted faces. We expected both groups to show the delayed N170 component when faces were inverted, but this effect should only occur in fingerprint experts for the fingerprints.

Here is the data:

The dashed lines come from faces, and the solid lines from fingerprints. The x-axis is time, with 0 the time that the stimulus (face or fingerprint) comes on. The y-axis is amplitude recorded from the back-right part of the head, which records mainly amplitude from the occipital/parietal region of the brain.

As predicted, the experts had a difference for both faces and fingerprints, but the novices had a difference only for fingerprints in the N170 component.

This result allows us to attribute the configural processing we observed in the behavioral experiment to changes in perceptual processing that occur very early on in the visual stream.


To summarize, the results of the two experiments provide converging evidence that the visual expertise gained by fingerprint examiners has profound effects on the earliest stages of visual processing, which has lots of potential to help them recover fingerprint detail from noisy or degraded images.

For More Information

To participate in future on-line (web-based) experiments, contact Tom Busey at Please specify if you have fingerprint experience.

The entire article may be accessed from Dr. Busey's publication page:

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