This group will receive an online two-week intervention to train the specificity and savoring of autobiographical memories. During the two-week intervention and the following two weeks, participants will complete continuous assessments (i.e. once a day) rate the their mood (positive and negative affect) as well as the level of positivity, specificity and savoring of positive memories recalled during practice session. For this study, we included continuous assessments to monitor essential project variables throughout the intervention (2 weeks; from Day 0 to Day 15) and then as a follow-up (2 weeks after; from Day 16 to Day 30).

This group will receive no intervention to train the specificity of autobiographical memories. During two weeks (from Day 0 to Day 15), participants will complete continuous assessments (i.e. once a day) to monitor their positive and negative affect.

An autobiographical memory specificity and savoring training has been developed by authors, based on previous training within the frame of Cognitive Bias Modification Interventions (CBM-I; Barry et al., 2019; Hitchcock et al., 2017) and savoring interventions (Bryant et al., 2005; Hanson et al., 2023). The training group will receive a self-guided intervention, which consists of an initial session (lasting 20 minutes approximately) and two-week training, conducted online. Participants will be provided with an online platform for following the intervention in a self-guided modality. The first session aims to give information about autobiographical memory functioning, to train in specificity recall through concrete processing steps and to explain the functioning of the self-guided modality. Then, during the next two weeks, participants will use the online platform once a day for practising the recall of autobiographical memories during 10-15 min approximately.

AMT is the preferred measure to evaluate the degree of specificity of autobiographical memory. During the AMT application, nine verbal cue words of different valence (three positive, three negative and three neutral) will be presented to the participants to perform a recall task of specific personal memories (Dritschel et al., 2014). The specificity of the memories is scored by evaluators following specified criteria (Williams et al., 2007), and then, an overall estimate of the level of specificity of autobiographical memories can be calculated. The assessment will be conducted online, following previous works with the written version of the AMT (Takano et al., 2017). The spanish adaptation (Ros et al., 2018) has shown adequate psychometric properties in young and older populations.

PHQ-9 is a nine-item self-report measure of depressive symptoms. Participants answer the statements using a four-point Likert scale (0= Not at all to 3=Nearly every day) (Kroenke, Spitzer & Williams, 2001). The Spanish version has shown comparable diagnostic validity to the original English version, presenting levels of 88% of sensitivity and 88% of specificity (Diez-Quevedo et al., 2001).