The Influence of Sleep on Declarative Memory in the First Year of Life
Final Report Abstract
The main aim of the project was to investigate relations between sleep and memory processing in the first year of life. In a series of four studies, we consistently found evidence of sleep and memory being closely intertwined early in life, extending previous findings obtained with adult populations. In all studies, we used an imitation procedure where a model demonstrated actions to infants using a hand puppet and the infants’ ability to reproduce these actions was assessed immediately (Study 2) or after delays of 4- (Study 1, Exp. 1; Studies 3 and 4) or 24-hrs (Study 1, Exp. 2). In Studies 1, 3 and 4, an experimental approach was used where infants were randomly assigned to nap, no-nap, and baseline control conditions, providing the opportunity to explore cause-effect relations. In Study 2, a correlational approach was used, supplementing the experimental data. In Study 1 we found that post-learning naps facilitated 6- and 12-month-old infants’ declarative memory consolidation. Study 2 revealed that high quality night sleep was associated with enhanced rates of immediate imitation the following day in 6- but not 12-month-olds. In Study 3 we found that post-learning naps facilitated 12-month-old infants’ ability to apply previously learned information to a novel stimulus. Study 4 showed that post-learning naps enhanced 12-month-old infants’ ability to extract the gist from a learning episode. Together, the studies suggest that sleeping behaviour is an important influence on early human memory. Overall, the project findings were in accordance with our predictions outlined in the original proposal. However, we had to adjust the procedures for Studies 3 and 4 as task difficulty was too high using the originally proposed procedure such that in the adjusted procedure, infants were allowed to practice the target actions prior to the delay. In addition we conducted these studies with 12-month-olds only. Testing fewer infants in Studies 3 and 4 gave us the opportunity to conduct an additional Study (i. e., Study 2) that had not been included in the original research plan. The findings from Study 1 have received international media attention (e.g., Frankfurter Allgemeine Zeitung, New York Times, BBC, TIME Magazine) and has featured in a wide range of sources from science (e.g., ScienceDaily.com, BioScholar.com) to health care (e.g., NHS Choices, NursingTimes.net, MedicalNewsToday.com) and educational and parenting websites (e.g., NurseryWorld.co.uk, Mother and Baby.com.au).
Publications
- (2014). Der Zusammenhang zwischen Schlaf und dem Lernen neuer Informationen bei 6- und 12- Monate alten Säuglingen [Relationship between sleep and learning of new information in 6- and 12-month-old infants]. 49. Conference of the German Psychological Society, Bochum, Germany
Konrad, C., Seehagen, S., Herbert, J., Lockmann, L., & Schneider, S.
- (2014). Does prior sleep facilitate the encoding of new information in 6- and 12-montholds? International Conference on Infant Studies, Berlin, Germany
Seehagen, S., Konrad, C., Lockmann, L., Schneider, S., & Herbert, J. S.
- (2014). Infant sleep and maternal well-being: Associations at 6 and 12 months after birth. International Conference on Infant Studies, Berlin, Germany
Konrad, S., Seehagen, S., Lockmann, L., Herbert, J., & Schneider, S.
- (2014). Naps enhance declarative memory in 6- and 12-month-old infants. International Conference on Infant Studies, Berlin, Germany
Konrad, C., Seehagen, S., Lockmann, L., Schneider, S., & Herbert, J. S.
- (2014). Schlaf unterstützt das deklarative Gedächtnis bei 6- und 12-Monatigen Säuglingen [Sleep facilitates declarative memory in 6- and 12-month-old infants]. 49. Conference of the German Psychological Society, Bochum, Germany
Seehagen, S., Konrad, C., Schneider, S., & Herbert, J. S.
- (2015). Sleep after learning enhances flexibility of memory retrieval in 12-month-old infants. 48th Annual Meeting of the International Society for Developmental Psychobiology, San Sebastian, Spain
Konrad, C., Herbert, J. S., Schneider, S., Lorek, S., & Seehagen, S.
- (2015). Timely sleep facilitates declarative memory consolidation in infants. Proceedings of the National Academy of Sciences of the United States of America, 112(5), 1625- 1629
Seehagen, S., Konrad, C., Herbert, J. S., & Schneider, S.
(See online at https://doi.org/10.1073/pnas.1414000112) - (2016). The relationship between prior night's sleep and measures of infant imitation. Developmental Psychobiology
Konrad, C., Herbert, J. S., Schneider, S., & Seehagen, S.
(See online at https://doi.org/10.1002/dev.21387)
