Memory Processes in Morning Recall after Multiple Night Awakenings

Abstract

Some episodes of mental sleep experience which are reported after multiple awakenings during sleep are not recalled in the morning. Have they decayed or are they temporarily inhibited to retrieval? Responses of 10 men were recorded for four non-consecutive nights; they were awakened each night four times after 9 win. of REM sleep. Upon each awakening they were asked to report their mental sleep experience, and in the morning they were asked to re-report these experiences. Where subjects were unable to provide a spontaneous morning report they were prompted using a probe, the probe being the first contentful proposition of the corresponding night report. Subjects were aware of this design. All the night and morning reports were subjected to linguistic analysis. Spontaneous morning reports were significantly less frequent than night reports, but the use of the probe significantly increased the frequency of morning reports. Both spontaneous and probed morning reports and their corresponding night reports shared similar linguistic structures, but the probed reports and their corresponding night reports were shorter. The percentage of contents common to night and morning reports was similar for both spontaneous and probed morning reports, as was the stability of the serial position of those contents. We suggest that, with respect to settings with only one night awakening, multiple awakenings increase retrieval difficulty for entire episodes of mental sleep experience but not for single contents.