Learning without One’s Knowledge


Subjects in an fMRI experiment had no idea their brain activity had been trained

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Weizmann Institute scientists have shown that it’s possible to launch a directed learning process in someone’s brain while that person is unaware that any learning is taking place at all.

Prof. Rafi Malach and his colleagues used positive and negative stimuli in an fMRI to produce unconscious learning

In a study reported in the Proceedings of the National Academy of Sciences, USA, postdoctoral fellow Dr. Michal Ramot, a member of the team of Prof. Rafael Malach of the Neurobiology Department, together with Shany Grossman, a graduate student in the department, and Dr. Doron Friedman of the Interdisciplinary Center, Herzliya, provided 16 subjects with rewarding or negative stimuli while their brain activity was monitored by functional magnetic resonance imaging (fMRI). The subjects were told that the purpose was to study reward mechanisms. When they heard a positive stimulus, a pleasant tone, they would receive a monetary reward; in contrast, they were informed that a negative stimulus, an unpleasant noise, would be accompanied by a fine.

Unknown to them, the researchers issued the positive stimuli when the fMRI detected a certain pattern of brain activity that appeared spontaneously in a particular brain region of the study subjects; the negative stimuli were given whenever another pattern, radically different from the first, was detected in that same region. After five days, the first pattern became significantly strengthened in the majority of subjects: The neuronal connections with other brain regions elicited by this pattern became more robust.

Brain imaging with fMRI reveals increased neuronal connectivity (yellow and orange), reinforced by neurofeedback, on days 2 and 3 of the study. Critically, participants were unaware that a training process was taking place

Scientists have in the past trained cortical networks by rewarding stimuli in a method call called neurofeedback, but this had been done in subjects who were aware of being trained and who sometimes were actively involved in the process. In the Weizmann study, the change in cortical networks – in other words, a focused learning process – had taken place in the brains of subjects who’d been unaware that they were learning anything. When questioned after the study, the subjects were oblivious of having been trained; when asked to make a guess, they failed to identify any kind of training they’d been subjected to.

“We’ve supported the notion that our brains can learn in a focused and directed manner even when we are not conscious of a learning process,” Malach said. “In the future, the method may be extended to achieving improved cognitive and brain function in individuals who are interested in training but lack the resources to focus – for example, those who are severely depressed or suffer from attention disorders. The approach is not ready for immediate application, however, because it necessitates the use of advanced fMRI research technology. Also, the changes we’ve induced in neuronal networks have been very mild and transient, so the method requires a lot of further optimization and testing. But we’ve shown how brain circuits can be trained in a targeted manner below the threshold of awareness. In addition, this study, along with other research in our lab, suggests that the still-mysterious spontaneous fluctuations in brain activity can be harnessed for such subconscious training. Future research, therefore, may explore how neurofeedback can be employed to alter, and hopefully improve, brain connectivity.”

The research of Prof. Malach is supported by the Murray H. and Meyer Grodetsky Center for Research of Higher Brain Functions, which he heads; the Lulu P. and David J. Levidow Fund for Alzheimers Diseases and Neuroscience Research; the Adelis Foundation; Friends of Dr. Lou Siminovitch; and the Leff Family, Calabasas, CA. Prof. Malach is the recipient of the Helen and Martin Kimmel Award for Innovative Investigation and the incumbent of the Barbara and Morris L. Levinson Professorial Chair in Brain Research.