A sprinter can begin moving just 150 milliseconds after hearing a starting pistol. If they’ve made an error though and started early, a new cascade of commands is needed to stop their feet from going further. There’s very likely a moment where the runner has come to the decision to stop running, although their legs don’t seem to have gotten the message yet, carrying them further forward for a few steps. Some of that is due to balance and inertia, but researchers from Johns Hopkins University have found that there’s plenty of mental inertia to overcome as well.
Steps needed to stop
To put it briefly, changing your mind is complicated. A decision isn’t a single thing in your brain, as scans of human and monkey brains have identified at least 11 brain areas that are involved in the process of changing your mind. This sort of mental bureaucracy isn’t just needed for complex tasks that require coordination of whole body, like sprinting or dancing. Even if you’re simply trying to reign in your gaze while looking at a computer screen, at least three brain areas need to issue new commands while communicating with eight others.
The latter scenario was obviously a little easier to test in a laboratory setting. Test participants were asked to look at the central part of a screen while waiting for a target to appear. The target didn’t appear in the center, and sometimes people were allowed to follow the instinct to glance at that new stimulus. Other times, the appearance of the target went along with a reminder to keep their eyes in the center of the screen, requiring a quick mental change in course. By measuring brain activity, researches could track which brain areas were then required to realize the “mistake” and issue new commands to the eyes.
The timing of ‘too late’
The sequence that emerged revealed a critical moment about one-tenth of a second after participants were reminded to look at the center of the screen. By that time, the command to look at the distracting target was being sent to the eyes, and could no longer be aborted by new thoughts forming in the brain. This would be the brief window where participants would be aware of their error but unable to do anything about it. It’s brief in the grand scheme of things, but just long enough to reveal an incongruity in how our brains interact with our bodies.
Knowing this may be useful for more than just informing us about our next moment of regret. Researchers suspect that disruptions in the process to change one’s course of action may have serious consequences, as it likely plays a role in self-preservation, risk-taking, and possibly drug addiction. A separate study of methamphetamine users found that their cravings extended the amount of time needed to change their behavior once an action had been started. This isn’t to say that this mental process explains drug dependencies, but it may help explain some of the tertiary effects of drug use that can make a bad situation even worse.
Source: Why Your Brain Has Trouble Bailing Out Of A Bad Plan by Jon Hamilton, NPR Shots