“For lie detection to be an adaptive skill, that helps us to avoid liars and befriend truth-tellers, it doesn’t have to be conscious alarm bells. It could be more subtle,” ten Brinke says. “More of a feeling that you don’t really want to lend this person twenty dollars, that you’re not excited to go on a second date with this guy.” Ten Brinke and her colleagues decided to focus their efforts on finding evidence for unconscious lie detection.