Listening differs from obeying. A person who receives and understands information or an instruction, and then chooses not to comply with it or to agree to it, has listened to the speaker, even though the result is not what the speaker wanted. Listening is a term in which the listener listens to the one who produced the sound to be listened.
Semiotician Roland Barthes characterized the distinction between listening and hearing as "Hearing is a physiological phenomenon; listening is a psychological act." Hearing is always occurring, most of the time subconsciously. In contrast, listening is the interpretative action taken by the listener in order to understand and potentially make meaning out of the sound waves. Listening can be understood on three levels: alerting, deciphering, and an understanding of how the sound is produced and how the sound affects the listener.
Alerting, the first level, is the detection of environmental sound cues. While discussing this level, Barthes mentions the idea of territory being demarcated by sounds. This is best explained using the example of one's home. One's home, for instance, has certain sounds associated with it that make it familiar and comfortable. An intrusion sound (e.g. a squeaking door or floorboard, a breaking window) alerts the dweller of the home to the potential danger.
Deciphering, the second level, describes detecting patterns in and interpreting sounds. An example of this level is that of a child waiting for the sound of his mother's return home. In this scenario the child is waiting to pick up on sound cues (e.g. jingling keys, the turn of the doorknob, etc.) that will mark his mother's approach.
Understanding, the third level of listening, means knowing how what one says will affect another. This sort of listening is important in psychoanalysis. Barthes states that the psychoanalyst must turn off their judgement while listening to the analysand in order to communicate with their patient's unconscious in an unbiased fashion.