Dissertations and Theses

Date of Award


Document Type





mood, memory, arcadian, rythyms


"Studies have proposed that sleep following the presentation of emotional information aids in the consolidation of memory for the emotional elements of the stimuli. Some of these studies have used a paradigm that may have been affected by the confounding influence of circadian factors. Mood may follow a circadian rhythm and research suggests that mood at the time of recall can influence the content of the memory recalled. This study was meant to determine whether the enhanced memory for emotional stimuli in the morning following a night of sleep is a function of the circadian rhythm of mood. Better recall of emotionally negative material in the morning may be due to circadian variation in negative mood resulting in enhanced emotional recall based on a mood-congruent effect rather than due to the consolidation of emotional memory caused by sleep. One hundred and fifty-one participants viewed negative and neutral scenes comprised of either negative or neutral objects on neutral backgrounds. After a night of sleep, 64 participants returned and were randomly assigned to a control group or to a positive or negative mood induction group. Participants then completed the recall and recognition tasks followed by the Morningness-Eveningness Questionnaire, a sleep diary, and a demographics questionnaire. Induced mood did not change participants’ performance on the recognition and recall tasks. It was found that participants’ mood was more negative in the evening that in the morning, and that induced mood did not affect recall or recognition memory. However, individual difference in mood at the time of learning, mood at the time of testing, and the percent of optimal sleep attained during the night between testing and learning were related to measures of performance on the recall and recognition tasks."



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