are more likely to trip over their words and unintentionally use filler language like “um” to draw out the conversation as they struggle to concoct a believable story or to remember a prefabricated narrative. “This is something that is hard to control,” explains Mihalcea. “When you are thinking about what you are going to say, the words are rational and logical to convince other people of what you want to in dialogue. But the other sounds, you can’t control as much,” and they may inevitably slip out despite a liar’s best attempt otherwise.