Autobiographical memories are memories one has of their life experiences. Although decades of research have provided insights into the mechanisms underlying memory retrieval from different perspectives (e.g., biological, cognitive, evolutionary, forensic, and clinical), there is still much about the retrieval process that is not well understood. The present thesis, therefore, aimed to bridge the gaps in the literature by examining autobiographical memory retrieval at both between-subjects and within-subjects levels. Given the multidimensional nature of autobiographical memory, the second chapter of this thesis explored whether and to what extent the six aspects of memory (i.e., memory accuracy, memory specificity, recollective experience, memory functionality, rumination, and executive functioning) are related. In the first study, 53 pairs of monozygotic and 39 pairs of dizygotic twins watched a video of a simulated theft and later answered a recognition test measuring accuracy for items in the video. In between, participants retrieved 10 personal events with the help of cues and rated these memories on recollective experience. They also completed questionnaires measuring functionality and rumination, along with five tasks measuring the mental flexibility, visuospatial processing, inhibition, and the forward and backward verbal learning processes of executive functioning. Findings from Study 1 revealed that not all aspects of autobiographical memory are related. Whereas rumination and memory functionality were related, memory accuracy, memory specificity, recollective experience, and executive functioning appeared to function more independently. To validate the findings of Study 1, a second study was conducted with a sample of 153 undergraduate students from the University of Nottingham Malaysia. Participants followed the exact same procedure as Study 1. Although the results of Study 2 largely resembled those of Study 1, Study 2 additionally found an association between recollective experience and memory functionality. Using the data from Study 1 of Chapter 2, Chapter 3 of this thesis examined whether the six aspects of autobiographical memory are heritable. Because most of the correlations from Studies 1 and 2 were not significant, we conducted two exploratory factor analyses to determine whether there were underlying factor structures across the different aspects. The factor analyses revealed one new factor: working memory capacity (which is a combination of visuospatial processing and forward and backward verbal learning). Despite some reliability issues, findings from Chapter 3 revealed support for additive genetic contributions to rumination and working-memory capacity. Whereas the previous chapters examined memory retrieval on a between-subjects level, Chapter 4 goes a level lower, and examines autobiographical memory retrieval on a more within-subjects level. Studies have shown that visual imagery and working memory are both important during the retrieval of autobiographical memories. However, their exact contributions during memory retrieval remains unclear. To address this gap in the literature, Chapter 4 compared the relative contributions of visual imagery and working memory during the retrieval of autobiographical memories using a dual-task paradigm. In the first study, 46 participants retrieved their autobiographical memories while following a moving dot, viewing a Dynamic Visual Noise (DVN), or viewing a blank screen. The memories retrieved were then rated on phenomenological properties, such as recollective experience, vantage perspective, emotional intensity, and emotional valence. Due to some technical and methodological limitations in Study 1, a follow-up study was conducted with 95 participants. Findings from both studies revealed that inhibiting visual imagery processing only delayed the memory retrieval process but did not affect the phenomenological quality of the memory retrieved. Furthermore, although taxing the working memory delayed the retrieval process, the phenomenological quality of the memories remained unaffected. The findings of the current thesis highlight the importance of examining autobiographical memory more holistically. For instance, the associations between functionality and rumination, and between functionality and recollective experience, found in the present thesis suggest potential mechanisms that warrant further investigation. Furthermore, because the present thesis found support for the influence of additive genetics on the rumination and working memory capacity aspects of autobiographical memory, future studies should aim to identify the genes associated with these different aspects as this would deepen our understanding of the contributions of additive genetics and the environment on autobiographical memory retrieval. A better understanding of autobiographical memory retrieval would also aid clinicians in increasing the efficiency of the treatment of different clinical disorders, like depression and PTSD. This in turn, would help people develop healthier coping strategies, and lead better lives.
Kristine Anthony (Sat,) studied this question.