Every final decision we make, choosing a new job or moving from the country, comes with a degree of hesitating whether we have made the right decision.
If your confidence is sufficiently low, you might change our minds and reverse our decision.
The scientists are using these choice reversals to study the first inklings of self-knowledge. Changes of your mind, reflect a precisely tuned process for monitoring our stream of thoughts.
There are two suggestion of thought on the issue of what it means to know oneself and how changes of mind play a role. One suggestion is that changes of mind occur because we continue to thing about evidence after a choice has been made. This process is called ‘post-decision evidence accumulation’. An alternative idea is that the brain corrects its mistakes by engaging additional mechanisms after settling on a course of action. People who have damage to the frontal regions of the brain might be uncapable to ‘self-monitor’ and identify errors they have made.
In recent studies, participants were asked to make final decision about what they saw on a computer screen. The studies highlights the way we monitor our internal thoughts, and how self-correction occurs.
In one of the study, researchers from Columbia University, Cambridge University, and New York University asked volunteers to decide whether a patch of flickering dots was drifting to the left or to the right by moving a handle in the corresponding direction. Volunteers could indicate confidence in their decision by moving the handle up or down. As soon as volunteers moved the handle, the dots in question vanished.
Most of the time, the participants moved directly to their chosen target, upper right, lower right, upper left or lower left. But every so often, volunteers changed their direction and level of confidence, mid-move.
Question is what was happening?
By evaluating these patterns of behavior to the predictions of a computer model, the researchers found evidence that we change our mind from the bottom-up. Even when the dots were no longer visible on the screen, volunteers continued to accumulate information in their neural pipeline, causing them to changes their decision, their confidence, or both.
A second team, from Trinity College Dublin and Leiden University in The Netherlands, has suggested another structure for how this works: from the top-down. Here, participants were outfitted with electroencephalography (EEG) caps to measure the brain’s electrical activity. After they were asked to press a button each time a color word such as ‘red’ appeared on a computer screen.
However, they were advised to not press the button if the word was repeated twice, or if the meaning of the word and the font color matched (for example, ‘red’ written in red text). This is a difficult task to perform quickly, and mistakes were made on 43 % of the trials on average. In order to assess self-monitoring, the participants pressed a separate button if they noticed they’d made an error.
So what did the researchers find?
A signal from the centroparietal area of the brain, known for integrating sensory information, ramped up to a threshold level after a choice was made. Showed that the same mechanism we use for perceiving external events is engaged when reflecting on internal decisions. Also, the researchers detected theta waves in the frontal cortex whenever errors were detected. This finding suggests that a ‘quick and dirty’ error signal in the frontal cortex can trigger the continued accumulation of evidence to work out whether a change of mind is warranted.
Both sets of studies confirm the importance of evidence accumulated after a decision has been made, but diverge on the source of this evidence. The Cambridge group suggests that an incoming stream of evidence is continually accumulated both before and after a choice has been made. By contrast, the Trinity College group advice that top-down signals information that feeds back to influence earlier stages of processing provide an additional input to enable changes of mind.
Diversity in the design of the two studies might limit the extent to which we can compare their findings. Suggesting that future research should combine the approaches for more definitive results. For instance, it would be valuable to monitor EEG during experiments like those performed at Cambridge to establish the relative contributions of bottom-up and top-down influences on changes of mind.
Psychologists have long been interested in metacognition, the ability to reflect on and evaluate our final decision and behavior. The neural basis of metacognition is likely to be complex and multi-faceted. The studies in question reveal that simple decision-making provides a good starting point.