Eli Loker is the lead researcher at the Lightman Group. This character conducts voice stress tests in order to see where various spikes take place, as these can indicate deception.
Eli possesses an interesting quality, as well: he refuses to lie. Loker has taken a pledge to be radically honest. Makes for a helpful dynamic at a company that makes a living trying to get at the truth.
(to Gillian) No, no, you don't want the muffins here. They're terrible. They taste like sofa cushions with the moldy nuts your grandmother used to keep in a little jar.Eli
Eli Loker: I would like to sleep with you.
Dr. Cal Lightman: Ah, Eli Loker, Ria Torres. He's harmless, just always speak the truth about what's on his mind. What do you call it again?
Eli Loker: Radical honesty.