Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Donald A. Williamson


Mood congruent memory (MCM) in depressed individuals, tends to be biased toward memories consistent with their mood, i.e. negative or unpleasant memories. Although MCM is a robust finding, the large majority of studies have used free-recall paradigms, and that methodology does little to delineate the cognitive mechanisms determining MCM. This study was designed to investigate whether MCM bias is a function of implicit or explicit memory. Implicit memory is taken as a measure of the organization or strength of association of the aspects of a memory representation, whereas explicit memory also taps elaboration that may involve control procedures such as retrieval strategies. Thus a comparison of implicit and explicit MCM bias may provide important information about the involvement of the structure of the memory representation, or the involvement of elaboration processes in MCM. Two groups, a group of clinical depressives and a comparison group, were studied. Each group engaged in an encoding task involving words of varying affective valence. Following this encoding task, all subjects engaged in an explicit memory task (cued recall), and an implicit memory test (word completion). As expected, a MCM bias was found in explicit memory, however, contrary to predictions, no MCM bias was found in implicit memory. This finding was interpreted as supporting the involvement of elaborative mechanisms in MCM. A second finding showed that MCM was found with depression items but not with physical threat words. Thus, the MCM bias in explicit memory is somewhat specific to information that is congruent with depression rather than to all negativistic information.