When people lean in to intently listen to what another person is saying, they usually instinctively turn their heads to the right side. There is a reason for this. Recent research has found that both children and adults rely more on their right ears for processing and retaining what they hear. This bias can largely be explained by the fact that sounds that enter the right ear are processed by the left side of the brain, which controls speech, language development, and portions of memory. Because young children’s auditory systems cannot sort and separate the simultaneous information from both ears, they depend more heavily on their right ears to capture sounds and information. For many, this preference persists into adulthood.  

P.S. According to the research mentioned above, study participants who listened to audio information through their right ears retained the information up to 40 percent more effectively.