This is your brain on freestyle rap

In an unlikely pairing, two professional rappers have teamed up with researchers from the National Institutes of Health to study what happens in the brain during freestyle rapping. The results, published Thursday in the journal Scientific Reports, suggest that the process is similar to that of other spontaneous creative acts, including jazz improvisation.

The study was initiated by the Los Angeles-based rappers Daniel Rizik-Baer and Michael Eagle and carried out by Allen Braun and Siyuan Liu of the NIH’s National Institute on Deafness and Other Communication Disorders. The researchers asked 12 rappers to memorize a set of lyrics that they then rapped while inside of a magnetic resonance imaging machine. The rappers also were asked to freestyle over music while in the MRI scanner. Then the researchers compared the images from the memorized and improvised rapping sessions to see whether the brain activity underlying the two tasks was different.

During improvisation, the researchers found less activity in parts of the brain typically involved in planning our actions and controlling complex behaviors. Meanwhile, they found greater activity in parts of the brain thought to underlie action. That led the authors to hypothesize that improvisation may involve bypassing a set of cognitive abilities that are together referred to as executive function. Such abilities allow us to plan and execute complex behavioral tasks, something that may be important for the performance of memorized music but less so for freestyling, where spontaneous generation of language is king.

Simply comparing differences in brain activity does not reveal the whole truth, however. That’s because the brain is made up of many interacting parts that have to work together. So the researchers also looked at a measure called functional connectivity, which allows them to see whether or not different brain areas are correlated with one another.

The researchers found that a network connecting areas implicated in language, emotion, and physical movement—and, importantly, lacking strong connections to areas involved in executive function—arose during improvisation.

While more research will need to be conducted to understand how this network fits into the creative process writ large, the authors of the study hypothesize that, during improvisation, high-level executive function is actively bypassed in order to allow for a more natural, spontaneous output of language. Such a hypothesis will be hard to prove in an fMRI scanner – all the researchers can truly say is that certain brain areas or networks of brain areas are more active in one task or another.

But the results of the rapping study closely parallel a 2008 study by Braun, suggesting that, as the authors write in the new study, “the neural mechanisms illustrated here could be generalized to explain the cognitive processes of other spontaneous artistic forms.”

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