It all started because researchers wanted to see how handedness influenced which ear people held their cell phones to. They surveyed over 700 people and found that 68% of right-handed people held their cell phones to their right ear, 25% to their left ear, and 7% had no preference. Similarly, 72% of left-handed people held their phones to their left ear, 23% to their right ear, and 5% had no preference. This isn’t just about the comfort of using your dominant hand: “More than 90% of the sound in the right ear goes to the left side of your brain and vice versa,” explains Michael Seidman, MD, director of otologic and neurotologic surgery in the department of otolaryngology-head and neck surgery at Henry Ford Hospital, and author of the study to be published online in JAMA Otolaryngology-Head & Neck Surgery. This means, if the language center of your brain is located on the left side, you probably hold your phone to your right ear so that the sound travels to the dominant brain region faster. This may explain why not everyone used their writing hands to hold their cell phones. So? Dr. Seidman says that this knowledge may help researchers identify whether people are left brain or right brain-dominant without costly tests. But here’s a just-for-fun way for you to find out yourself: While the large majority of people are left-brain thinkers, you may have your language center located on the right (an indication of creativity) if you’re right handed, but you hold your phone with your left hand. The reasoning: this could explain why you don’t use your dominant hand to hold your phone. Cool, huh?