The TSA can’t seem to win. It spent millions of dollars on body scanners that were derided as invasive and ineffective, and now its attempt to train agents to read body language seems to be misguided, as well. The agency spent over $1 billion training special “behavior detection officers,” a program that science suggests is ineffective.

It turns out that using body language to determine whether somebody is lying is really quite hard. You can test your own acuity with this New York Times interactive. But according to Nicholas Epley, who studies behavior, “body language speaks to us, but only in whispers.” John Tierney at the New York Times explains that the $1 billion spent on training TSA officers was probably a waste. Last year, the program was reviewed by the Government Accountability Office, which looked at both the results of the initiative and about 200 studies on behavior analysis. Tierney writes:

In those studies, people correctly identified liars only 47 percent of the time, less than chance. Their accuracy rate was higher, 61 percent, when it came to spotting truth tellers, but that still left their overall average, 54 percent, only slightly better than chance. Their accuracy was even lower in experiments when they couldn’t hear what was being said, and had to make a judgment based solely on watching the person’s body language.

Tierney runs through a series of commonly taught behavioral “tip offs” that law enforcement agents and others learn. Things like: liars look up and to the right, while truth tellers look up and to the left. (Not true, by the way.) Several studies have suggested that it’s far more telling to actually listen to what the person is saying, than it is to watch how they say it. “When you’re lying or cheating, you know it and feel guilty, and it feels to you as if your emotions must be leaking out through your body language,” Epley told Teirney. “You have an illusion that your emotions are more transparent than they actually are, and so you assume others are more transparent than they actually are, too.” But in fact, nobody can tell you’re freaking out inside. Not even specially trained TSA agents.