Cognitive onsultants International   Cognitive Consultants International

Forensic Fingerprinting

Forensic fingerprint examiners require specific cognitive abilities to perform their job. We have identified the elements that comprise the cognitive profile of abilities for fingerprint examiners. Then we scientifically developed and validated tests that measure and quantify those abilities. The development of the tests  has been supported by funds from the US National Institute of Standards and Technology (NIST), US Department of Justice (both the National Institute of Justice (NIJ) and the Federal Bureau of Investigation (FBI)), and the Department of Defense (DoD).   

We developed these tests because there are no scientifically developed or validated cognitive tests for fingerprinting. Some labs use general cognitive tests that do not tap onto the specific cognitive abilities needed for this domain (for some examples, see 'general cognitive tests'). Some labs use the Form Blindness tests, which is not intended to test abilities, but is suppose to detect deficits (for details, see 'Form Blindness Test').

Our test scientifically measure, among other things, the following cognitive abilities, specifically tailored to fingerprinting:
1. Attention allocation
2. Visual mental imagery:
    a. inspection
    b. rotation
    c. transformation
3. Dealing with and filtering noise
4. Perceiving and comparing:
    a. curvatures
    b. width
    c. features
    d. orientation
5. Visual search   

We briefly elaborate on these, below:  
1. Attention Allocation: One of the cornerstones of the human cognitive system is that it has limited computational capacity and resources, and therefore, it cannot process all the information that is provided as sensory input to the brain (Knudsen, 2007; Posner, Snyder, and Davidson, 1980; Sperling, 1960). The result is that the cognitive system selectively allocates attention and cognitive resources. This process requires us to constantly engage and disengage attention and shifting attentional focus and cognitive processing to different segments of the visual input (Wright and Ward, 2008; Posner and Petersen, 1990).

The ability to allocate attention to the important and most crucial information defines much of the human cognitive system and intelligence. This process of selectively and wisely knowing where to focus attention gets better and more refined with expertise (Dror, in press). Selective attention is one of the cognitive ways of achieving expert level performance (e.g., Wood, 1999). As one becomes a greater expert, they get more selective, paying only attention to the important pieces of information, at an ever increased rate and accuracy. While a novice is still trying to absorb the information and make sense of it, the expert has already focused on the critical information (e.g., Valk and Eijkman, 1984), processed it, and solved the problem. The process of selection is critical. For example, expert radiologists selectively process X-ray films according to clinically relevant abnormalities (Myles-Worsley, Johnston and Simons, 1988; Valk and Eijkman, 1984). This results in efficient and effective processing.
In fingerprint work, experts must allocate attention to the pieces of information that will help them reach a conclusion; points of similarity as well as discrepancies.

2. Visual mental imagery: Visualizing images in the 'mind's eye' is a common cognitive process, in fact:
"Most people use mental imagery to help them perform everyday tasks. For example, when trying to recall the color of a car, one may create a 'mental picture' of the car and 'look' at it; or when shopping for a new sofa, one might visualize how one’s room would look if the sofa were placed against a particular wall. Imagery can be used not only in memory and reasoning, but also in other cognitive tasks. One of the most fundamental discoveries about imagery is that it has a complex underlying structure." (Dror and Kosslyn, 1994, p. 90)

Mental imagery, however, is not a single cognitive process, and is comprised from a whole set of mental abilities. Some of these are especially important and characteristic of tasks that are important for experts in certain domains, such as Air Force pilots (Dror, Kosslyn, and Waag, 1993), musicians (Aleman, Nieuwensteina, Böckerc, and Haana, 2000), and designers (Kavaklia and Gerob, 2002).

For fingerprint experts, three visual mental imagery are especially important:
a. Image Inspection: This process enables to visualize and inspect an image (for details, see Cooper and Podgorny, 1976; Dror and Kosslyn, 1994; Dror, Kosslyn, and Waag, 1993; Busey and Vanderkolk, 2005). Often fingerprint examiners compare friction ridges by visually examining one and comparing it to another they are visualizing.
b. Image Rotation: This process enables to imagine an image in different orientations (for details see, Shepard and Metzler, 1971; Dror, Ivey, and Rogus, 1997). Visual mental rotation is often used by fingerprint examiners when they have a small latent mark and they are trying to find the corresponding area on a 10-print.
c. Image Transformation: This process enables to mentally reconstruct and modify visual images (for details see, Shepard and Cooper,1982; Shepard and Feng, 1972). Distortions often affect friction ridge, and fingerprint examiners need to imagine the print without the distortions, thus mentally modifying and recreating a 'distortion free' image in their mind.

3. Dealing with and filtering noise: Visual information provided to the cognitive system is rarely 'noise free'. Along with the 'signals' which contain the sought out information needed to perform the task, the input also contains 'noise'. For the cognitive system to make sense of the signals (e.g., recognize patterns, evaluate and judge the significance of the information, and interpret the meaning of it), it must first deal with and filter out the noise (Busey and Vanderkolk, 2005; Lu, Lesmes, and Dosher, 2002; Harmon and Julesz,1973; Solomon and Pelli, 1994; Dosher, and Lu, 1998). Experts are very good at ‘seeing through the noise’ (Busey and Dror, in press).

The work of fingerprint examiners often involves working with images that contain noise. Latent prints are rarely 'noise free'; they contain noise originating from the dirt and other prints that were on the surface, as well as from the powers and chemicals used for detecting and lifting the prints, the process of capturing and digitizing the images, and other artifacts. Fingerprint examiners' ability to deal with and filter such noise, seems to play an important part in their work.

4. Perceiving and comparing: One of the fundamental abilities of the human visual system is to perceive visual information, encode its characteristics, and compare them against other images. These visual characteristics are many, and depend on what is unique and informative for the task at hand (Dror, Stevenage, and Ashworth, 2008; Kundel and Nodine, 1983; Ashworth and Dror, 2000; Biederman, 1987). Some of the most relevant visual information used by fingerprint examiners are:
a. Curvatures: The ability to perceive, judge, and differentiate between different curvatures.
b. Width: The ability to perceive, judge, and differentiate between different widths.
c. Features: The ability to perceive, judge, and compare different minutia and other features that appear within friction ridge.
d. Orientation: The ability to perceive, judge, and compare different orientation of lines.
5. Visual search: Before perceiving and comparing curvatures, width, and features; dealing with noise; and allocating attention (see above), one must first scan the visual input and search it, so as to detect regions of interest within the image (Wolfe, 1994; Czerwinski, Lightfoot, and Shiffrin, 1992; Nobre, Sebestyen, Gitelman, Frith, and Mesulam, 2002). This is an important ability for fingerprint examiners, as they need to visually search the friction ridge to find which regions have the information most valuable for them, i.e., containing information that they can use to reach a conclusion.

These cognitive processes constitute part of the cognitive profile of fingerprint examiners, which our tests measure.

To inquire about taking these tests, go to: Obtain Details for Testing.

If you have been authorized for testing, then go to: Start Testing Ver 1 (for Version 1) and to Start Testing Ver 2 (for Version 2).


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