Previous experiments have looked at unconscious decision making. A new paper (citation below) confirms those experiments and adds more information.
The authors are looking at the hypothesis that extrastriate and prefrontal neural regions are active during the encoding of decision information and continue to process that information during a subsequent distractor task. “It is possible that reactivation occurring in these extrastriate-hippocampal-dorsolateral prefrontal regions might support continued visual and semantic processing of decision information during an unconscious thought period.” It has been shown by others that a period of unconscious thought can led to better decisions than a period of conscious thought or an immediate decision without a period of thought of either kind, at least with certain types of problem – large, vague, disorganized ones. These researchers confirmed previous results but with fMRI scans to add information on the areas of the brain that were involved.
They used a 2-back memory task as a distractor that made conscious thought on anything but that task impossible. The scans were during: 2-back task alone, 2-back task while making the decision unconsciously, making the decision consciously. The participants first encoded the information need to make the decision and then went on to make the decision consciously or unconsciously. This encoding phase was also scanned.
When the activity associated with the 2-back task was subtracted from the unconscious thought, the remaining activity was in the prefrontal cortex, right thalamus and left frontal operculum. Activity was seen in the left intermediate visual cortex and right dorsolateral prefrontal cortex during encoding and during unconscious thought. The reactivation of the encoding activity predicted the decision-making performance. Neural regions involved in encoding decision information continue to process this information outside of conscious awareness. Conscious thought, on the other hand, had activity in a prefrontal network that did not overlap with any regions active during unconscious thought.
The nature of the unconscious mind has long challenged philosophers and scientists, but the present work offers a new perspective on this topic by way of examining the brain. We find that brain regions that are active during encoding new decision information reactivate while the brain coordinates responses to other unrelated tasks, when participants are prompted to make decisions.
I think it is important to look at the 2-back memory task. This makes very great demands on the working memory and practically no other facility – no arithmetic or logic needed. This is why it works so well at shutting down conscious thought and does not seem to infer with unconscious thought. But this clean division is not likely to be the normal state. Use of working memory, consciousness and unconscious cognition are likely to be active together and in cooperation (except in sleep). What is shown is what unconscious thought is capable of but not how is may be normally used.
Creswell, J., Bursley, J., & Satpute, A. (2013). Neural Reactivation Links Unconscious Thought to Decision Making Performance Social Cognitive and Affective Neuroscience DOI: 10.1093/scan/nst004