While much neuroscientific research has focused on active processes like decision making, perception, and motor control, there are a myriad of background functions running in our brains that “fill in the gaps”.
The default mode network is thought to mediate a lot of “internal” or “introspective” processes during wakefulness, like thinking, pondering, daydreaming, and also internalizing or thinking about other people’s emotional states. This latter process allows us to consciously perceive and think about what others around us are thinking, which involves a certain level of empathy and internalization of one’s own emotions. This is an area of neuroscience that is garnering a lot of attention, and spans topics including ‘consciousness‘, ‘theory of mind‘, and social and affective influences to neurological processes. Rooted in philosophy, these areas of research are now finally getting the empirical research backing they need to take them from ‘pseudo-science’ to the real deal.
So what exactly happens in our brains when we daydream? How and why do we try to imagine what other people are feeling or thinking? These are both important processes that allow us to formulate creative ideas and actively adjust our behaviour based on the people around us. At True Impact, we are interested in understanding these processes and how they influence the relationship between consumer behavior, external influences, and preferences. However, how and where in the brain do these processes occur?
Studies on the default mode network seek to answer this latter question, and a recent paper by Mark Eldaief and colleagues published in Social Cognitive and Affective Neuroscience discusses the role of the default network in processing emotional (or affective) and cognitive information during inductive reasoning. These researchers were able to show subregions within the overall default network that are preferentially activated by emotional (happy versus sad) and cognitive (certain versus uncertain) information. To do this, participants were presented with three statements: two arguments followed by a third statement that participants were required to answer whether they deemed it ‘probably true’ or ‘probably false’ via button press while in an fMRI. From the figure below, we can see that the processing of emotional (and specifically, negative emotion) information during inductive reasoning preferentially activates the dorsal medial prefrontal cortex (red + yellow), and if the arguments presented in the syllogism led to a more certain conclusion about the final statement, then the anterior and ventral portions of the medial PFC were activated (blue + green).
So what does this really mean? What does this location-specific information tell us about making decisions based on the presentation of emotional and logical information?
It means that portions of our prefrontal cortex – the area of our brain that takes the longest to develop and mature, and underlies the most complex behavioral and social processes in our daily lives – are specialized to process certain types of information when we are drawing conclusions and actively and internally reasoning. When the information we get is emotional (sample syllogism: A mother and father died at the same time. Their son was with them at that moment. Their son probably died with them), dorsal and medial portions of the PFC are activated. When the information we get is certain (sample syllogism: An athlete broke a world record. The record was broken in a certain sport. The athlete is probably good at that sport.), anterior and ventral portions of medial PFC are activated.
Eldaief and his colleagues were able to further pinpoint which specific areas within the overall default mode network process specific types of information that we use daily to inform our everyday opinions, beliefs, and decisions through inductive reasoning. These results also clarify some of the important functions performed by the diffuse default mode network that we implicitly depend on in our day-to-day interactions with the world around us.