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Selected Development Project
Project Title

Sleep on It: Effects of Daytime Naps and Nighttime Sleep on Emotional Processing in College Students

Principal Investigator Dr LAU Esther Yuet Ying
Area of Research Project
Psychological Studies
Project Period
From 01/2017 To 12/2018
  1. To experimentally determine the effects of a daytime nap on three kinds of emotion-related cognitive functions, including (1) emotional memory, (2) emotional reactivity, and (3) inhibitory control in the affective domain in healthy young adults.
  2. To examine if the electroencephalographic (EEG) characteristics, namely REM sleep duration and latency in the nap are associated with post-nap changes in emotional and cognitive functions.
  3. To investigate the impact of prior chronic sleep restriction on the relationship between napping and emotional processing.
  4. To explore the potential effects of pre-existing sleep patterns on the EEG features of the experimental nap.
  5. To explore the potential associations between the EEG features of the nap and subsequent night-time sleep.
Methods Used
200 young adults wore actigraph and completed sleep diary throughout the study protocol as an assessment of their sleep-wake pattern. Participants sleeping less than 6 hours nightly were classified as Short sleepers. On the experimental day, inhibitory control performance was assessed using an Affective Go/No Go (AGNG) task at two sessions, during which neutral, positive and negative faces were used as stimuli signalling Go and No-Go responses. In between the testing sessions, participants were randomized to remain awake or have a 90-minute polysomnography-monitored napping opportunity. Performance on the AGNG between habitual Short/Normal sleepers and Nap/Wake conditions were compared to elucidate the effects of a daytime nap on affective control in individuals of different sleep durations.
Summary of Findings
  • The inhibitory control performance of all groups deteriorated across the day.
  • Short sleepers without a nap had more trouble inhibiting responses induced by the neutral faces than Short sleepers with a nap or Normal sleepers with or without a nap.
  • Short sleepers benefited more from napping than Normal sleepers as their inhibitory control performance for negative faces was comparable to Normal sleepers in the Wake condition.
  • In contrast, a daytime nap did not benefit the Normal sleepers in their inhibitory control performance for negative faces.
  • The benefits of napping on inhibitory control in response to negative faces were found to associate with a specific sleep stage - Rapid eye movement (REM) sleep.
  • Our results highlighted the role of sleep in daytime emotional functioning in terms of controlling our responses to emotional stimuli.
  • Our findings provided preliminary support to the use of strategic napping as a compensation for inadequate night-time sleep among college students for enhancement of emotional functioning.
Selected Output

  1. Lau, E. Y. Y., Wong, M. L., Tseng C. H, Lau, K. N. T., Chung, K. F., & Rusak, B. (2017, October). Influence of chronic short sleep and a daytime nap opportunity on emotion-related inhibitory control in young adults.Poster presented at World Sleep 2017 Congress, Prague, Czech Republic.
  2. Shapiro, C.M., Lee, Y.J., Gooley, J.J., Lau, E.Y.Y., & Shahid, A. (2017, October). Suicide, sleep and circadian rhythms in adolescents. Symposium presented at World Sleep 2017 Congress, Prague, Czech Republic.
  3. Wong, M. L., Lau, N. T., Chung, K.F., Rusak, B., & Lau, E.Y. Y. (2017 June) Youth’s bedtime regularity mediates the association of depression and anxiety with negative attention bias. Poster presented at SLEEP 2017, the 31st Annual Meeting of the Associated Professional Sleep Societies LLC (APSS).
Biography of Principal Investigator

Dr Lau Esther Yuet Ying is an Assistant Professor of Department of Psychology, member of Centre for Psychosocial Health, and the Coordinator of the BSocSc (Psy) Programme of The Education University of Hong Kong. She completed her doctoral training at Dalhousie University, Vancouver Coastal Health, and the University of British Columbia, Canada, specializing in clinical psychology and clinical neuropsychology. She is a registered clinical psychologist of the Hong Kong Psychological Society and a registered psychologist of British Columbia, Canada. Her clinical and research interests include the interaction between sleep and daytime functioning, neuropsychology of medical and psychiatric disorders, and spirituality and mental health. Currently, her primary line of research aims to uncover some of the complex relationships between sleep, emotional and cognitive functioning. She is also actively involved in a series of longitudinal investigations on the various psychosocial factors contributing to the formation and transformation of beliefs in Chinese.

Funding Source

General Research Fund