The current study aims to reduce the intolerance of uncertainty levels with an internet-based cognitive bias modification intervention in young adults with high levels of intolerance to uncertainty aged between 18 and 40. Furthermore, it aims to examine the intervention's effectiveness on their intolerance to uncertainty, positive and negative emotions, depression and anxiety symptoms, and repetitive thinking.

Intolerance of uncertainty, a common factor in mental disorders (playing a transdiagnostic role), is critical to the development and maintenance of emotional problems (e.g., depression and anxiety) as it disrupts people's daily functioning. Studies have shown that intolerance of uncertainty is closely related to psychological problems, highlighting its importance for psychological interventions. Particularly considering the transdiagnostic nature of intolerance of uncertainty, attempting to reduce this trait in individuals also provides further intervention opportunities for various problems. Therefore, reducing intolerance of uncertainty is the focus of psychotherapy studies. The cognitive-behavioral conceptualization of intolerance of uncertainty emphasizes that people are unable to tolerate uncertainty because they misinterpret ambiguous situations in a biased manner, which leads to psychological problems. Accordingly, intervening in intolerance of uncertainty involves the modification of one's biased interpretations. At this point, Cognitive bias modification (CBM) is a method that involves paradigms in which a person is exposed to a series of stimuli to alter and reduce cognitive biases related to psychopathology. In recent years, the effectiveness of CBM in different psychological problems has been proven. In addition, current studies aim to reduce psychological symptoms through the use of CBM targeting transdiagnostic features and have shown promising results. Despite the importance of intolerance of uncertainty, only one study was found in the literature that examined the effect of CBM on intolerance to uncertainty in a randomized controlled design. In that study, it was concluded that a single-session CBM was successful in reducing intolerance to uncertainty by reducing interpretation biases in individuals. However, the study has some methodological shortcomings and requires further investigation in different samples. From this point of view, the present project aims to investigate the effectiveness of CBM on intolerance of uncertainty. The proposed project will examine the effect of internet-based CBM, focusing on interpretation bias related to uncertainty, on reducing intolerance of uncertainty and general psychological symptoms using self-report and behavioral measures in a randomized controlled design. In this way, the project aims to make a scientific contribution to the relatively limited literature in this area and to reduce participants' emotional symptoms by reducing their intolerance of uncertainty.

Inclusion Criteria:

• Participants' willingness to participate in the CBM-I (Cognitive Bias Modification - Intervention)
• Having high levels of intolerance of uncertainty (receiving scores higher than the median of the initial sample by splitting the data based on the median)
• Having computer and internet access.

Exclusion Criteria:

• Being outside the targeted age range
• Having a psychiatric diagnosis and receiving current treatment
• Scoring psychotic questions and suicide questions above the midpoint on the Brief Symptom Scale
• Having color-blindness

It is planned to add some files to the OSF (Open Science Framework) link created for the study.

Participants will be blinded to which condition they are assigned to. Participants will be assigned codes so that the care provider is also blinded to which condition the participants are in.