Music perception is a process that connects hearing with impressions of sounds in the brain. Since music is considered a phenomena that can only be experienced through auditory perception, many psychologists report that people can only be truly aware of music's existence while hearing it. The study of music perception is often divided into different areas concerned with how the brain reacts to pitch, melody, harmony, and rhythm. Various factors such as cultural backgrounds and natural sensitivities to sound variations can affect different people's perception of the nuances in a given piece of music.
Pitch is a common focus of music perception because changes in pitch make it possible for notes to be arranged into the patterns that make up various melodies. Some psychologists point out problems with sound perception in this context due to variations in the exact definition of a melody. Melodies can also be found in speech and in other sources of sound that are not considered music. Listening to these kinds of sounds can be designated a perception of melody but not necessarily of music. The same principle can apply to perceiving other general components of sound such as rhythm and intonation.
Music perception is usually considered different from general sound perception because songs and instrumental pieces contain a definite characteristic that other types of sound do not have. This trait is often called musicality, and it refers to a specific set of responses in the brain that occur when a listener hears a pattern of rising and falling pitches. Brain scans of people listening to a piece of music show different areas of activity than in the brains of people who are listening to other kinds of sound. Many studies of music perception attempt to define a precise meaning behind music and to explain whether that meaning exists independently of music when no one happens to be hearing it.
Emotional responses are also tied to music perception. A popular idea is that music expresses definite emotions depending on its pitches, tempos, melodies, and harmonies. Psychologists who study music cognition often report that this aspect of perception is the most subjective. Different people tend to like different types of music depending on their life experiences, education levels, and sometimes their cultural heritage. The melody and structure of music can differ significantly from one culture to the next, and people's perceptions of it can also be affected by their immediate emotional responses.