Hallucinations are defined as "any percept-like experience which (a) occurs in the absence of an appropriate stimulus, (b) has the full force or impact of the corresponding actual (real) perception, and (c) is not amenable to direct and voluntary control by the experiencer."(Slade and Bentall,1988). Great. Now you know. Just kidding. So what is this really saying.
Auditory hallucinations can range from primitive noises such as bangs, whistles, claps, screams, ticks, and others to speech and music.Commonly people who have auditory hallucinations hear voices which utter short comprehensible phrases. Sometimes the person may recognize the voice as one of a family member or deceased friend and sometimes it may be the voice of a stranger or even God. The voices or sounds can be thought to originate from anywhere. The walls, the ground, trees, a shoe are all possible origins of hallucinatory sounds.
Schizophrenics characteristically have auditory hallucinations. A common type of auditory hallucination of a schizophrenic is a voice which refers to the patient in the third voice calling him/her worthless or useless and no-good. Sometimes there is a running commentary and at other times there are whispers. Sometimes auditory hallucinations may take on the form of imperative statements asking the patient to kill someone or themselves. One type of auditory hallucination that is peculiar to schizophrenics is called "echo de pensees which is the type of hallucination where a patient hears his own thoughts out loud and feels that everyone can hear him thinking. Auditory hallucinations are very weird!!! Ralph Hoffman at the Yale University medical school has proposed a theory that since the development of feeling which are not physically present happens in normal people all the time during dreams , that it is probably not just the presence of voices that cause create problems for schizophrenics, but that it is the conflict between the voices and the will of the schizophrenic patients that make the symptom so aversive.
Another theory about the development of auditory hallucinations has been proposed to be caused by agitated arousal leading to mia attribution of internal thoughts to external voices( Klemperer, 1996)
How we hear normally is when sound waves vibrating on our ear drums cause our ear drums to send the vibrations through the inner ear ossicles, which bangs on the cochlea, sends a vibrational signal through the cochlear fluid, which sets of signals through the neurons to the brain. Then we perceive the sound.(If you have no idea what I just said and need to brush up on some ear anatome and function, check out the link for the physiology of the ear on our main page.) The sound is heard by us only when our auditory cortex receives the information from the ear and interpretes this, converting it into a form our brain perceives as a particular sound. When there is no external source of sound waves our ears do not normally register any sound to our brain and so we do not hear anything. Auditory hallucinations may occur when there is no source of sound waves, but a sound is still perceived. An sound heard could also be an auditory hallucination is the normal source of the sound waves is not what produces the sound heard . If you hear a voice calling you every time you everytime you bounce a ball, an object is producing sound waves, but the sound you hear is not the appropriate auditory response to the stimulus( the ball). This could also be counted as an auditory hallucination.
Auditory hallucinations must have the same impact as that produced by a normally occuring stimulus sound. What this means is that in order to call an imagined sound an auditory hallucination, it must be appear to the person perceiving it as the real thing. What I'm saying is that imagined voices are not auditory hallucinations since you know that you did not actually hear tham the way you would hear the sound through your ear normally. If it does not appear to be a real sound in the way you would normally experience sounds, then we don't call it an auditory hallucination.
Our definition of an auditory hallucination also eliminates the those types of sounds which we can control the perception of. If we are able to make a sound be heard ourselves, and are able to control when we hear the sound, then its not an auditory hallucination by our definition.