But as the researchers themselves point out, understanding what makes a person like a particular food is a complex knot of biology and psychology, influenced by her sensitivity to tastes and odors as well as past experiences. The researchers even had trouble deciding which foods to use as examples for bitterness because different people describe the tastes differently. And although the study makes a good case for a correlation between "dark personalities" and a preference for bitter flavors, it doesn't provide any information about what might cause that preference—is it biology or psychology, or both? Though the researchers don't mention any intention to conduct any future studies to explore the cause of these preferences, that information might be even more valuable than the study at hand.