or, one might add, not in the room. For example, I was recently food shopping and chatting on my cell with my sister, Although my sister was not with me physically, as is typical of my personality, I was focused, not on the cereal and boxes of Pop Tarts in front of me, or on the other sounds around me, but on my sister's voice alone. Vaguely, I though I could hear my mother calling my name. Although the store was crowded with strangers, and my attention was diverted, I could recognize my mother's unique vocal tones. However, because my attention was upon my sister, I didn't realize what my mother was saying, and only after I said good-bye did I realize that my mother had been asking me to clarify if my sister wanted chunky or creamy peanut butter. I knew my mother was speaking despite the mixture of different and unfamiliar voices in the store, but I could not focus what she was saying because of my interest in my sister....

Thus, this is one example of how being better able to juggle competing auditory stimuli might be something I need to work on as a listener.
Furthermore, speaking on a cell phone divides the consciousness in a unique way, because quite often the listener's attention is on the person her or she is talking to, not what is in front of the listener or on the other sounds in the room. This is why it can be dangerous to drive while talking on a cell phone. It is sometimes better to actively minimize competing auditory stimulus, when danger is involved.

Interestingly, music does not divide my consciousness while driving or walking around a store in the same way that a person's voice can -- I am not distracted by background music in a store or while I am studying, but another person's voice can prove a distraction, if I feel I must listen that individual and remember the meaning of what he or she is saying.