Understanding Psychology (10th Ed)

 
Module 12 
Hearing and the Other Senses 
117
sounds, whereas frequency theory explains what happens when low-frequency 
sounds are encountered. Medium-frequency sounds incorporate both processes 
(Hirsh & Watson, 1996; Hudspeth, 2000). 
After an auditory message leaves the ear, it is transmitted to the auditory cortex 
of the brain through a complex series of neural interconnections. As the message is 
transmitted, it is communicated through neurons that respond to specifi c types of 
sounds. Within the auditory cortex itself, there are neurons that respond selectively 
to very specifi c sorts of sound features, such as clicks and whistles. Some neurons 
respond only to a specifi c pattern of sounds, such as a steady tone but not an inter-
mittent one. Furthermore, specifi c neurons transfer information about a sound’s loca-
tion through their particular pattern of fi ring (Middlebrooks et al., 2005; Alho et al., 
2006; Wang et al., 2005). 
If we were to analyze the confi guration of the cells in the auditory cortex, we 
would fi nd that neighboring cells are responsive to similar frequencies. The auditory 
cortex, then, provides us with a “map” of sound frequencies, just as the visual cortex 
furnishes a representation of the visual fi eld. In addition, because of the asymmetry 
in the two hemispheres of the brain (which we discussed in the last chapter), the left 
and right ears process sound differently. The right ear reacts more to speech, while 
the left ear responds more to music (Sininger & Cone-Wesson, 2004, 2006). 
Speech perception requires that we make fi ne discriminations among sounds that 
are quite similar in terms of their physical properties. Furthermore, not only are we 
able to understand what is being said from speech, we can use vocal cues to deter-
mine who is speaking, if they have an accent and where they may be from, and even 
their emotional state. Such capabilities illustrate the sophistication of our sense of 
hearing (Fowler & Galantucci, 2008; Massaro & Chen, 2008; Pell et al., 2009).