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The Secret To Controlling Unwanted Thoughts

This new study says there’s a difficult but effective way.

In moments of heightened anxiety and stress, my intrusive thoughts take over. I’ll be making coffee in the morning and a voice in my head will, randomly, tell me all my friends from last night are talking about me behind my back. And I’ll spiral into questioning whether everything I’ve ever said is stupid, and cannot stop myself from thinking about it obsessively.

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As a science journalist who writes about health and the mind, “thoughts” are a concept I am enthralled by, so this mechanism also becomes something to research and study rather than just experience. Today, I want to ask: How does one control such insidious, unwanted thoughts?

Usually, when trying to avoid unwanted thoughts, you reject the thought and try to replace it with something else — “think about how much fun you had last night, think about how much you laughed!” Yet, science shows that even just thinking about that bad thought in the first place has already reinforced and strengthened said thought in your mind, allowing for it to garner enough energy to keep coming back in an endless loop.

Now, science shows that there might be a much more efficient way to proactively avoid these thought associations in the first place, according to a new study published July 14th, 2022, in the journal PLOS Computational Biology.

“I really think of this study as the first building block in trying to understand the question of how people regulate their thoughts and make sure, to an extent, that they don’t look into thoughts that might be very distressing,” Isaac Fradkin, a computational psychiatry researcher at The Hebrew University of Jerusalem and lead author of this study, told me when I interviewed him for this article.

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Thoughts, as you can imagine, are very obscure to science because they’re very abstract. “The basis of knowledge is somewhat limited in this regard,” says Fradkin, albeit the extensive research in the field. “And part of the problem has to do with the fact that most of the instances in which we are sort of aware of trying to control a thought are instances in which this thought has actually already invaded our consciousness.”

So, Fradkin and his team looked into how 80 English-speaking people played a word-association game. The participants saw one common word on the screen and had to type out an associated word. Some words would be repeated several times, randomly, across the experiment. For example, they saw the cue ‘table’, not one time, but six times, sprinkled among other words. One group of participants was told not to ever repeat the associations — or they wouldn’t get the experiment money — so they had to swiftly come up with alternative associations when the words repeated themselves.

“So you see the cue ‘table’, you write ‘chair’ in the first instance, and then a few trials after that you see ‘table’ again, and your task is not to write ‘chair’ again,” says Fradkin. “And then the question is, how do you do that? Do you first sort of think of the chair in your mind and then have to suppress it somehow, or ignore it, or replace another association? Or can you actually reduce the probability that the association will come to mind in the first place?”

To answer this question, the researchers therefore calculated how long it took participants to effectively generate new word associations and came up with a mathematical formula made of a set of equations that tries to approximate, according to reaction time, when people were using “reactive control” and when people were using “proactive control”.

Photo by Anna Schvetz on Pexels

To understand reactive and proactive control, it might be helpful to consider yourself driving a car, waiting at a red light to turn left, says Fradkin. Imagine that you suddenly see a traffic light turning green, and only after that do you realize that this light is only relevant for cars continuing straight. Thus, you ignore this traffic light only after it has already captured your attention. This is an example of reactive control over attention. Now, consider the many pedestrian traffic lights at the junction which you completely ignore even if they suddenly turn green. These lights will likely not capture your attention at all. You can filter them out before they grab your attention. This is an example of proactive control over attention, Fradkin notes.

The same distinction can be made for thoughts: reactive control over thoughts means that you try to stop thinking a certain thought after it has already reached consciousness. Proactive control means you can filter this thought from reaching consciousness altogether, or at least — reduce the probability that it will come to mind, says Fradkin.

“The basic intuition behind using reaction times here is that if indeed you use ‘reactive thought control’, it is a process that usually takes time,” says Fradkin. “Conversely, if you can use what we call proactive control, you might be able to sort of think of an alternative new association, without consuming any extra time for the rejection part.”

The results showed that, mostly, people tend to carry out “reactive control”. Like I often do with my morning coffee and the haunts of my friends loathing me.

One of the reasons this happens, Fradkin notes, might specifically be because of the self-reinforcing nature of memories: if you thought of the association table-chair once, it naturally makes it more probable that you will think of it again.

Yet, the mathematical model shows that, in some cases, people can actually partially preempt this process. Specifically, according to the parameters, the participants weren’t avoiding unwanted associations altogether, but they were actively decreasing the probability of the associations happening again and again.

“The people who were allowed to repeat associations showed a very strong rehearsal strengthening effect, and people in the ‘suppress group’ were able to weaken this effect, to some extent,” says Fradkin. “This is something that I think is very optimistic because it suggests that, to some extent, we are able to somewhat unconsciously block some associations.”

This finding is, in fact, in agreement with the prior work of Todd Braver, a professor of psychological & brain sciences at Washington University in St. Louis who participated in coining that very “dual mechanism of control framework” — proactive and reactive control. With a computational approach like that of Fradkin's, “it is possible to parse out the behavioral data in a way to richer evidence for one strategy versus another,” says Braver, who was not involved in the study.

“This was kind of a very first step, but it opens the door to a lot more research to see how much of the experimental conditions constrain or encourage participants to do one thing or another adopt one strategy or another,” says Braver. Especially whether this differs according to the thinker. In fact, his own research has already shown that people with more advanced working memory tend to be more flexible in their ability to switch between proactive and reactive control of thoughts.

Fradkin too has already found some preliminary evidence that how people perform this task is actually related to how they experience themselves, in terms of how they think about their ability to control their intuitive and wanted thoughts in their daily lives — if they think they’re good they’re more likely to be good.

Photo by Sayantan Kundu on Pexels

The content of the thoughts also matters in the differentiation between these two methods of control, according to Thomas Hills, the co-director of the Global Research Priority in Behaviour, Brain & Society at The University of Warwick. “Negative and positive thoughts are different breeds of thought, and emotional thoughts are also likely to be different from unemotional thoughts,” says Hills. “We know that emotional things tend to be remembered better than unemotional things. They are also likely to be more intrusive, especially negative thoughts.” This is almost certainly by evolutionary design, Hill explains, because if something is likely to harm you, even if it’s only currently a figment of your imagination, you are better prepared to avoid it.

“This research is important because, above all, it tells us something about being human. Thoughts pop into our minds. Some of them are unwanted. Part of being human is learning how to deal with unwanted thoughts,” says Hills. “This research also shows that unwanted thoughts don’t just go away because we want them to. It takes effort. It takes an act of will not to accept all that comes into our heads.”

The next steps in work like this are focusing on more free-form thoughts, like what kinds of things come to mind in various situations and why are these more or less challenging to deal with under varying circumstances, says Hills.

In fact, this is just a little glimpse into the world of thoughts, Fradkin notes. There is so much more research to carry out, moving forward, with greater samples of participants, especially in order to better understand how to help people in clinical settings for psychiatric populations, according to Fradkin. Carrying out these experiments while simultaneously tracking what’s going on inside the brain, through the advances of neuroscience, as well as trying this out in more natural settings, could also help create a clearer picture.

“Even though our thoughts are mostly associated, we don’t think in these individual words — we think in much more complex ways,” says Fradkin. “So now the question here is how we can use this basic framework and model to try and study something more realistic of how people actually experience their daily thoughts?”


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