Neuroscientists at the University of California Berkeley observed the brains of 16 patients to witness how the brain processes human thoughts. The study found as to why people have the tendency to respond even before knowing what the response will be. Simply put, the brain is eager to response in some tasks that people usually find themselves “speaking without thinking.”
The neuroscientists were able to record the actual electrical activity of neurons directly from the surface of the brain by literally getting inside the skull of 16 patients as their heads were being opened for epilepsy surgery. The scientists used electrocorticograhy (ECoG), a technique where hundreds of electrodes were placed on the brain surface to detect activity in the region of the brain where thinking occurs.
This video demonstrates how the prefrontal cortex coordinates brain activity to help people act in response to a perception of a simple repetitive task. In this case, words are represented both visually and aurally.
NOTE: For a simple word repetition task, the brain received (yellow), interpreted (red) and responded (blue) within a second, during which time the prefrontal cortex (red) coordinated all areas of the brain involved.
This next video shows how the brain reacts when the given task is much complex. In this case, the stimulus is determining the antonym of the word. It can be observed that the brain required a few seconds to respond. The brain scientists explained that this is because the brain invited all its parts to participate in the task:
NOTE: For a more difficult task, like saying a word that is the opposite of another word, people’s brains required 2-3 seconds to detect (yellow), interpret and search for an answer (red) and respond (blue), with sustained prefrontal lobe activity (red) to coordinate all areas of the brain involved.
The key finding of the study was the brain prepares the motor areas to respond very early in simpler tasks.
“This might explain why people sometimes say things before they think,” Avgusta Shestyuk, a senior researcher in UC Berkeley’s Helen Wills Neuroscience Institute and lead author of a paper explained.
“This is the first step in looking at how people think and how people come up with different decisions; how people basically behave,” he said further.
The study is published in Nature Human Behaviour.