Sleep Quality and Subjective Tiredness on Associative Memories

Associative memory (AM) is the ability to make an association between two unrelated items. AM tasks are administered in a range of settings, for example in the clinical diagnosis of a cognitive impairment and in psychological experimental research. External factors such as tiredness, time of day (ToD) and caffeine intake may affect scores on cognitive tests. Understanding the influence of such external factors on AM is important to help accuracy of scoring the tests. In this study, forty cognitively-healthy young adults completed a sleep, tiredness and caffeine questionnaire followed by an AM task. Significant effects on the AM task of sleep quality and subjective tiredness rating were observed. Participants reporting higher sleep quality the night before the testing session recognised more AM pairs correctly. Furthermore, as current subjective tiredness rating increased, participants recognised fewer correct AM pairs. Overall, these novel findings highlight the need to consider an individual’s self-reported sleep quality the night before the testing session as well as their subjective tiredness rating at the time of testing when administering AM tasks. This may have important implications for the accuracy of scoring AM performance in clinical and research settings where such tasks are administered.