If the left side of the brain is typically dominant in language processing and the right side is dominant in emotional processing, then what happens when emotions are communicated through language? That's the very question that a team of researchers investigated. They subjected the participants to several tests while studying the activity level on both sides of their brains by the speed of blood flow on both sides.
Subjects were asked to listen to dozens of prerecorded sentences and to focus on either the actual words of the sentences or to focus on the emotions conveyed in how the words were spoken, the voices' tone and intensity. What was said, as well as how it was said, fell into five categories: happy, sad, anxious, angry or neutral. Examples of sentences heard included "The little girl lost both her parents," indicating sadness semantically, and "He really enjoys that funny cartoon," indicating happiness.
Researchers used ultrasound to measure the speed of blood flow in subjects' brains as they pointed to cards marked with one of the five emotions. Researchers found that when participants were asked to focus on the meaning of what was said, their blood flow sped up on the left sides of their brains, the side that processes language.
When they were asked to focus on how the sentences were said, however, blood flow sped up on the right sides of their brains, the emotional side of the brain. Interestingly though, blood flow was still fast on the left sides of subjects' brains too. The researcher's explanation is that the left brain automatically processes what is said, whereas how something is said is less automatic.