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
