do not hear changes within one phoneme category. Only changes from one phoneme to another phoneme are detected (Lobacz, 1984).Although categorical perception generally is considered to reflect the operation of a special speech decoder, there is a strong indication that categorical perception can also occur in non-speech signals. Musicians are a good example of this. The discrimination performance of musicians was better for frequency changes that revised the identity of the chord than for changes that did not alter the identity (Moore, 1997). Categorical perception is not unique to speech, however it appears more frequently with speech than with non-speech signals. There are three possible explanations for categorical perception. The first explanation suggests that consonants and vowels may be explained in terms of differences in the extent to which the acoustic patterns can be retained in auditory memory. Consonant sounds have a lower intensity than vowels, fluctuate more rapidly, and last for a shorter time than vowels. Therefore, the acoustic patterns of consonants frequently decay rapidly. Another explanation is that boundaries, which separate one speech sound from another, tend to lie at a point where discrimination is optimal. The last explanation is that it comes from experience with a person’s own language. In this explanation it is believed that a person learns to attend to acoustic differences that affect the meaning of a word and ignore the differences that do not affect the meaning. The natural consequence of this is categorical perception (Moore, 1997). Brain SpecializationLanguage functions are unilaterally represented in one of the two hemispheres. It is most commonly found in the left hemisphere. Therefore, the right ear will identify speech stimuli better than the left ear. This occurs because the neural pathways cross from the ear to the brain (Studdert-Kennedy and Shankweiler, 1970). Interesting...
