The ability to learn about the consequences of our actions is critical for survival. Reinforcement learning (RL) provides a framework for formally studying learning and has inspired a significant reconceptualization of its underlying neural mechanisms.
Now, using an MRI scanner, scientists from the Department of Experimental Psychology, the Wellcome Centre for Integrative Neuroimaging (WIN) and the Nuffield Department of Clinical Neurosciences observed changes in parts of the brain associated with learning and learned experiences while volunteers completed tasks that involved a reward.
Instead of focusing on the PEs that occur during learning, we focused on the knowledge or associative structures that are formed by the learning process.
To do this, participants learned not just associations between a single stimulus and reward but between chains of stimuli leading to rewarding as well as the statistical relationships between stimuli regardless of reward. This allowed us to test whether the associative structures derived from different learning processes might prove more distinguishable than their PEs.
They found that the changes seen in the participants’ neural pathways associated with learning were different depending upon how each person had learned the new skill.
Miriam Klein-Flugge of the Department of Experimental Psychology, said: “We know that humans can learn in different ways. Sometimes we learn simply by observing relationships in the world, such as learning the layout of a new town, or relationships between people. But another way to learn is by setting particular goals, like children learning to operate toys by trial and error.”
“This research shows that we have multiple networks in the brain that help us store learned knowledge or associations, which means that damage to one part of the brain will still leave alternative mechanisms available for learning.”
“We also learned that some of this knowledge is very persistent, and the brain does not forget about it even when it becomes irrelevant, while knowledge acquired through alternative learning mechanisms is more flexible and can more easily be changed to new knowledge.”
The study shows that the brain can learn in different manners and that these multiple mechanisms for learning rely on the concerted effort of numerous various brain networks. Also, it suggests that unlearning associations can be easier when they were acquired by observation compared to a goal-directed manner.
Miriam Klein-Flugge added: “It is well known that it is good for our brains to continue to learn new things throughout life, which is why understanding the different ways in which we learn and store knowledge could be beneficial and help each of us to find out which way of learning suits us best.”
The study is published in Nature Communications.