The Human Brain Evolved to Appreciate Speech and Music

As you probably already know, the homo sapien species is quite similar to other primates. As a matter of fact, we have so much more in common, genetically, than we have different.  Obviously, we share much with mammalian cousins but are similarities are more than just physiological; and the miniscule amount of difference we have appears to result in something dramatically unique.  

For example, existing studies have discerned that the brain of humans and nonhuman primates process visual information in nearly identical ways.  But while we have a shred appreciation for aural cues, researchers remain unclear about whether or not we perceive sounds the same way as our primate cousins.  

With that in mind, scientists at United States National Institutes of Health National Eye Institute, Bethesda, MD, and the Massachusetts Institute of Technology, in Cambridge, MA set out to learn more about this trait.  In a new study, the research team compared how the brains of humans compare with those of rhesus macaque monkeys in terms of audio perception. In particular, the researchers wanted analyze reactions to predominantly human sounds. This includes not just things like speech but also harmonic tones and music. 

In the paper, the study authors dictate, “Speech and music contain harmonic frequency components, which are perceived to have ‘pitch.’ Humans have cortical regions with a strong response preference for harmonic tones versus noise.” 

So the question is whether or not the same is true for non-human primates. 

To answer this question, researchers compared the responses of three rhesus macaques and four human study participants to audible harmonic tones and noises across the spectrum of five frequency rages.  Through functional MRI images, the team determined that there is not much difference between humans and monkeys, in this regard. 

However, more detailed brain scans showed that human brains are more sensitive to harmonic tonal “pitch” than rhesus macaque brains.  Essentially, while both species respond similarly to sound, the addition of tonal structure appears to be uniquely appreciated by the human brain. 

According to lead study author Bevil Conway, PhD, comments that the researchers found “a certain region of our brains has a stronger preference for sounds with pitch than macaque monkey brains.”

Furthermore, Conway notes that these results increase the potential that these sounds, which are inherent to both speech and music, might have shaped the fundamental structure and function of the human brain. 

The results of this study have been published in the journal Nature Neuroscience.