Abstract:
It is now firmly established that remembering the past and imagining the future rely on common underlying cognitive and neural processes, with both abilities involving retrieval of autobiographical memory (AM) and being self-referential in nature. These processes are also closely related to other features of subjective experience, including identity, emotions, and personal goals. Given these links, it may be of no surprise that alterations in remembering the past and imagining the future are associated with various forms of psychopathology. In Major Depressive Disorder (MDD), the literature has focussed primarily on two different qualitative aspects of past and future thinking: specificity and emotional valence. Specifically, MDD is characterised by a tendency to generate past and future events reduced in specific quality (i.e., overgenerality) and predominantly negative in emotional valence (i.e., negative bias). The studies in this thesis investigate the nature of specificity and emotional valence of both past and future autobiographical events in MDD. In Study 1, we investigated the specificity of both past and future autobiographical events, using two scoring methods to assess event specificity: the commonly-used Autobiographical Memory Test (AMT) and that of the Autobiographical Interview (AI). Study 1 replicates previous findings suggesting reduced specificity of autobiographical events in MDD. Study 1 extends on these findings to suggest overgeneral thinking in MDD is particularly marked for future thinking. In Study 2, we examined the content and emotional valence of both past and future autobiographical events. Study 2 replicates previous findings suggesting a negative bias in the processing of remembered and imagined autobiographical events in MDD. Expanding on previous findings, the results of Study 2 suggest that MDD is characterized by a tendency to generate more negative and fewer positive autobiographical events, irrespective of temporal direction (e.g., past or future). These findings indicate that alterations in specificity and emotional valence affect both memory recall and future thinking in MDD, and suggest that both may contribute to the onset and maintenance of depressive illness.