For now, though, the general attitude among federal agencies is that as new lie detection technologies emerge, they will likely be used to enhance the polygraph, which is a relatively inexpensive and simple way to test for the truth. Equipment for measuring eye blushing, hesitation, twitching, or even brain activity could be incorporated into the machine, says Andy Ryan, chief of research at the Department of Defense Polygraph Institute, which oversees polygraph examiners for federal agencies. Alternatively, these technologies, particularly high-priced and bulky equipment like fMRI scanners, could become the lie detection equivalent of a second opinion. "It's like taking a treadmill test to see if your heart is OK," says Ryan. "Your doctor would never diagnose heart problems from the results of a single treadmill test, which just offers a pattern subject to interpretation and further examination. It's the same way with a polygraph."