‘Sticky thinking’ hampers decisions in depression

Though low mood is the best-known symptom of depression, indecisiveness and biased thinking are also common. But these problems, which can lead to delays in making important choices — and being more likely to make poor ones — receive less attention, write the authors of a recent paper in Emotion.

Many of the theories that have been put forward to explain difficulties with decision-making are based on work suggesting that depressed people are not as responsive to rewards, or punishments, as healthy people, note Hang Yang and Marieke van Vugt at the University of Groningen. However, there is some evidence that rumination — excessive thinking about the causes and consequences of negative feelings and events — could also disrupt decision-making by making it harder to navigate between and weigh up options.

Yang and van Vugt decided to explore this idea in more detail. Firstly, they gave 124 candidate participants a questionnaire that assessed their level of depressive symptoms, and another that asked not only about how often they ruminated, but how difficult they found it to stop — the pair termed this 'sticky thinking'. The researchers note that the participants who scored relatively highly for sticky thinking also tended to have higher levels of depressive symptoms, and vice versa.

A total of 21 participants who had scored relatively highly for sticking thinking and 19 who had ranked relatively low then spent ten minutes writing about a negative topic that had been bothering them in their daily lives. (This was designed to increase the occurrence of ruminative thoughts during the main part of the experiment.) Then, while their brain activity was monitored using EEG, they completed a series of screen-based tasks, for which they had to press a key whenever they saw a word in lowercase letters, but not press anything if a word in uppercase letters appeared.

Every so often during these trials, they were prompted to report on what they'd been thinking about. Options included the task itself, personal things, and daydreaming, for example. If they hadn't been thinking about the task, they were asked how difficult they found it to disengage from that thought. This was a measure of the stickiness of their thinking.

Yang and van Vugt found that the participants who reported more sticky thinking made more mistakes on the task. Also, those who had scored relatively highly in the initial sticky thinking questionnaire took longer to decide to hit a key, when that was appropriate.

When the researchers looked at the EEG data, they also found that periods of sticky thinking were accompanied by an increase in alpha wave activity, which has been linked in earlier work to daydreaming and an unfocused mental state.

Yang and van Vugt conclude that "the study supported the idea that sticky thinking could explain the decision-making impairment among individuals who are more vulnerable to depression and worry."

There is one particular limitation that's worth nothing, however: 17 of the 21 participants who'd initially scored highly for sticky thinking were women, while the other group was reasonably gender-balanced. Further research is now needed to investigate whether this gender difference might have had any impact on the results.

Read the paper in full:
Yang, H., & van Vugt, M. (2025). "Sticky" thinking disrupts decision making for individuals with a tendency toward worry and depression. Emotion, 25(4), 997–1010. https://doi.org/10.1037/emo0001449

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