The next time you see a couple together, take a few minutes to observe how the partners interact with each other. Based on what you see, consider what you might be able to determine about their relationship. It seems reasonable that you could tell whether they enjoy spending time together or if they’re fighting. But based on your brief observation, could you pick out a cheater? It may sound implausible that anyone could accurately and quickly determine whether someone is cheating on a partner based on a quick observation like this. But researchers from Brigham Young University and Florida State University thought it may be easier than we might think and conducted a series of two studies to get some answers.