As part of their incredible audible abilities, the slight change in sound from different positions of the ears can help a dog pinpoint its source. (dogingtonpost.com)
Typically, it's not the noise itself that wakes your baby, but the sudden change in sound that jars your baby from sleep. (nocrysolution.com)
In one authoritative review of the science, researchers recommend white noise to help block out sharp changes in sound and create a peaceful sleep environment. (blog.cloudb.com)