A team of neuroscientists and engineers have developed a system that can show the neural process of decision making in real-time, including the mental process of flipping between options before expressing a final choice.
In the course of deciding whether to keep reading this article, you may change your mind several times. While your final choice will be obvious to an observer – you’ll continue to scroll and read, or you’ll click on another article – any internal deliberations you had along the way will most likely be inscrutable to anyone but you. That clandestine hesitation is the focus of research, published Jan. 20 in Nature, by Stanford University researchers who study how cognitive deliberations are reflected in neural activity.
These scientists and engineers developed a system that read and decoded the activity of monkeys’ brain cells while the animals were asked to identify whether an animation of moving dots was shifting slightly left or right. The system successfully revealed the monkeys’ ongoing decision-making process in real-time, complete with the ebb and flow of indecision along the way.
“I was just looking at the decoded activity trace on the screen, not knowing which way the dots were moving or what the monkey was doing, and I could tell Sania [Fong], the lab manager, ‘He’s going to choose right,’ seconds before the monkey initiated the movement to report that same choice,” recalled Diogo Peixoto, a former postdoctoral scholar in neurobiology and co-lead author of the paper. “I would get it right 80 to 90 percent of the time, and that really cemented that this was working.”
In subsequent experiments, the researchers were even able to influence the monkeys’ final decisions through subliminal manipulations of the dot motion.
“Fundamentally, much of our cognition is due to ongoing neural activity that is not reflected overtly in behavior, so what’s exciting about this research is that we’ve shown that we can now identify and interpret some of these covert, internal neural states,” said study senior author William Newsome, the Harman Family Provostial Professor in the Department of Neurobiology at Stanford University School of Medicine.
“We’re opening up a window onto a world of cognition that has been opaque to science until now,” added Newsome, who is also the Vincent V.C. Woo Director of the Wu Tsai Neurosciences Institute.
