Scientists can now better explain how best friends can finish each other’s sentences, after a recent experiment from UC Berkeley psychologists revealed a new link between language and memory.
This relationship between language and memory is centered at the hippocampus — a structure in the brain that processes sentences as we hear them by retrieving information stored in our memory, according to neuropsychologist and co-author of the research study Nina Dronkers.
“We’ve known for some time that language and memory had to be related,” Dronkers said. “But we’ve never really understood how exactly they interact and how the structure of the brain plays in the process. … This (discovery) is that concrete proof.”
One of the researchers who conducted the experiment, former UC Berkeley postdoctoral fellow Vitória Piai, said the hippocampus is essential to understanding not only how our memory works but also how we learn.
To carry out the experiment, Piai and her team recorded from electrodes that had been placed in the patients’ brains by the neurosurgical team in order to treat epilepsy. They would then ask the participants to complete fill-in-the-blank sentences.
Subjects would then be shown a picture of the missing word and were asked to identify it. Half of the given sentences were straightforward with easily identifiable missing words, while the other sentences required more critical thinking in order to name the missing word.
The experiment found that participants were faster at completing the more straightforward sentences because they had additional context and information that they could identify. Additionally, the study found that the activity that occurs in the hippocampus leaves a particular “signature,” or reaction, in the brain. This reaction appears more clearly in the left hemisphere of the brain than the right.
“One of the things that I didn’t do in this particular study is to compare directly if the signature of the hippocampus is the same if the patients are doing a memory task instead of a language task,” Piai said, adding that she wants to understand what happens to the language of patients when the hippocampus is damaged.
According to Piai, the study was funded by the Netherlands Organization for Scientific Research and UC Berkeley psychology professor and former head of the Helen Wills Neuroscience Institute Robert Knight with funding from the National Institute of Health.
Knight said a neuroscience experiment has three qualifications: anatomy, behavior and physiology. He added that when these requirements are met, strong claims can be made about behavioral instances.
“(The experiment) had all three things that made a great experiment,” Knight said. “(Piai’s) taken language into a new direction.”
A previous version of this article may have implied that professor Robert Knight helped fund the study out of pocket. In fact, he helped fund the experiment with his existing funding from the National Institute of Health.
A previous version of this article incorrectly stated that Vitória Piai and her team inserted electrodes into subjects’ brains to conduct the experiment. In fact, the electrodes had already been inserted into subjects’ brains by a different neurosurgical team treating epilepsy.