Mechanisms of Change of Positive Interventions in Reducing Vulnerability for Depression

Inclusion Criteria: In order to be eligible to participate in this study, all participants must meet all the following criteria: * Participants should be between 18 and 60 years old. Participants should not exceed 60 years of age in order to minimize aging-related decline in information processing; * Participants should display normal intelligence (IQ\>85, as assessed with the Dutch Adult Reading Test and/or having finished an education on at least vocational level) in order to assure sufficient task comprehension. Participants in the remitted Major Depressive Disorder group should meet the following criteria to make sure that participants are at high risk of depressive relapse and currently show no clinically relevant severity of depressive symptoms: * Remitted participants should have experienced at least two depressive episodes, according to criteria defined by the Diagnostic Statistical Manual, version 5 (DSM-5), experienced in past ten years; * Remitted participants should score 21 or lower on the Inventory of Depressive Symptomatology (IDS-SR30), indicative of the absence of clinically relevant depressive symptoms. Exclusion Criteria: Furthermore, individuals who meet any of the following criteria will be excluded from participation in this study: * Fulfilling criteria for any current DSM-5 diagnosis as objectified with the Structured Clinical Interview for DSM-5 (SCID-5); * Daily use of anti-depressive medication, benzodiazepines, methylphenidate, beta blockers or other medication potentially influencing electrocardiogram currently or in the last four weeks; * Recent engagement (defined as in their last episode, or as one year prior to inclusion in case the last episode was more than a year before inclusion) in preventive cognitive therapy including the positive fantasizing technique and/or have recent experiences (defined as daily practice in the past two years for at least two weeks) with mindfulness, meditation, or mindful yoga. This criterion prevents underestimation of true effects of mindfulness and/or positive fantasizing and maximizes treatment effects; * Participation in another clinical intervention study at the moment of inclusion in the study to prevent overlapping intervention effects. Individuals for the Never-Depressed control group who additionally meet any of the following criteria will be excluded from participation of this study: * Presence of symptoms of depression according to the IDS-SR30 (score \> 13), to make sure participants are not currently experiencing clinically relevant depressive symptoms; * Any life-time psychopathology of any disorder as objectified with the SCID-5.