During infancy, humans typically spend most of their time asleep. It is intuitively plausible that this state is important for development and well-being. But there has been a surprising dearth of knowledge regarding the causal role of sleep for specific cognitive processes during this period. Recent experimental evidence has revealed a causal role of sleep for early memory processes. By supporting the consolidation and further processing of recently acquired memories, sleep shapes emerging knowledge networks. In addition, infants’ sleep patterns likely shape their learning environment by influencing caregiver sleep and behavior. Based on recent research, recommendations for policy and practice include (a) allowing individualized sleep schedules in child care settings, (b) providing easily accessible information on sleep and sleep promotion to caregivers, (c) integrating findings from sleep research in the training of early childhood educators, and (d) providing flexible parental leave arrangements that promote sufficient sleep in infants and caregivers.
BarrR.DowdenA.HayneH. (1996). Developmental changes in deferred imitation by 6- to 24-month-old infants. Infant Behavior and Development, 19(2), 159–170. https://doi.org/10.1016/S0163-6383(96)90015-6
BergerR. H.MillerA. L.SeiferR.CaresS. R.LebourgeoisM. K. (2012). Acute sleep restriction effects on emotion responses in 30- to 36-month-old children: Sleep restriction and emotion in toddlers. Journal of Sleep Research, 21(3), 235–246. https://doi.org/10.1111/j.1365-2869.2011.00962.x
4.
BergerS. E.ScherA. (2017). Naps improve new walkers’ locomotor problem solving. Journal of Experimental Child Psychology, 162, 292–300. https://doi.org/10.1016/j.jecp.2017.04.021
5.
BritoN. H.FiferW. P.AmsoD.BarrR.BellM. A.CalkinsS.FlynnA.Montgomery-DownsH. E.OakesL. M.RichardsJ. E.SamuelsonL. M.ColomboJ. (2019). Beyond the Bayley: Neurocognitive assessments of development during infancy and toddlerhood. Developmental Neuropsychology, 44(2), 220–247. https://doi.org/10.1080/87565641.2018.1564310
6.
DearingE.McCartneyK.MarshallN. L.WarnerR. M. (2001). Parental reports of children’s sleep and wakefulness: Longitudinal associations with cognitive and language outcomes. Infant Behavior and Development, 24(2), 151–170. https://doi.org/10.1016/S0163-6383(01)00074-1
7.
DiekelmannS.BornJ. (2010). The memory function of sleep. Nature Reviews Neuroscience, 11(2), 114–126. https://doi.org/10.1038/nrn2762
8.
EdnickM.CohenA. P.McPhailG. L.BeebeD.SimakajornboonN.AminR. S. (2009). A review of the effects of sleep during the first year of life on cognitive, psychomotor, and temperament development. Sleep, 32(11), 1449–1458. https://doi.org/10.1093/sleep/32.11.1449
9.
Engle-FriedmanM.MathewG. M.MartinovaA.ArmstrongF.KonstantinovV. (2018). The role of sleep deprivation and fatigue in the perception of task difficulty and use of heuristics. Sleep Science, 11(2), 74–84. https://doi.org/10.5935/1984-0063.20180016
10.
FriedrichM.MölleM.FriedericiA. D.BornJ. (2020). Sleep-dependent memory consolidation in infants protects new episodic memories from existing semantic memories. Nature Communications, 11(1), 1298. https://doi.org/10.1038/s41467-020-14850-8
11.
FriedrichM.WilhelmI.BornJ.FriedericiA. D. (2015). Generalization of word meanings during infant sleep. Nature Communications, 6, 6004. https://doi.org/10.1038/ncomms7004
HayneH.BonifaceJ.BarrR. (2000). The development of declarative memory in human infants: Age-related changes in deffered imitation. Behavioral Neuroscience, 114(1), 77–83. https://doi.org/10.1037/0735-7044.114.1.77
16.
HemmiM. H.WolkeD.SchneiderS. (2011). Associations between problems with crying, sleeping and/or feeding in infancy and long-term behavioural outcomes in childhood: A meta-analysis. Archives of Disease in Childhood, 96(7), 622–629. https://doi.org/10.1136/adc.2010.191312
17.
HerbertJ.HayneH. (2000). The ontogeny of long-term retention during the second year of life. Developmental Science, 3(1), 50–56. https://doi.org/10.1111/1467-7687.00099
18.
HeymannJ.SpragueA. R.NandiA.EarleA.BatraP.SchickedanzA.ChungP. J.RaubA. (2017). Paid parental leave and family wellbeing in the sustainable development era. Public Health Reviews, 38(1), 21. https://doi.org/10.1186/s40985-017-0067-2
19.
HorvathK.HannonB.UjmaP. P.GombosF.PlunkettK. (2018). Memory in 3-month-old infants benefits from a short nap. Developmental Science, 21(3), e12587. https://doi.org/10.1111/desc.12587
20.
HorvathK.HannonB.UjmaP. P.GombosF.PlunkettK. (2018). Memory in 3-month-old infants benefits from a short nap. Developmental Science, 21(3), e12587. https://doi.org/10.1111/desc.12587
21.
HorváthK.MyersK.FosterR.PlunkettK. (2015). Napping facilitates word learning in early lexical development. Journal of Sleep Research, 24(5), 503–509. https://doi.org/10.1111/jsr.12306
IglowsteinI.JenniO. G.MolinariL.LargoR. H. (2003). Sleep duration from infancy to adolescence: Reference values and generational trends. Pediatrics, 111(2), 302–307. https://doi.org/10.1542/peds.111.2.302
24.
KonradC.DirksN. D.WarmuthA.HerbertJ. S.SchneiderS.SeehagenS. (2019). Sleep-dependent selective imitation in infants. Journal of Sleep Research, 28(1), UNSP e12777. https://doi.org/10.1111/jsr.12777
25.
KonradC.SeehagenS.SchneiderS.HerbertJ. S. (2016). Naps promote flexible memory retrieval in 12-month-old infants. Developmental Psychobiology, 58(7), 866–874. https://doi.org/10.1002/dev.21431
26.
LandryS. H.SmithK. E.SwankP. R.AsselM. A.VelletS. (2001). Does early responsive parenting have a special importance for children’s development or is consistency across early childhood necessary?Developmental Psychology, 37(3), 387–403. https://doi.org/10.1037/0012-1649.37.3.387
27.
LouisJ.CannardC.BastujiH.ChallamelM.-J. (1997). Sleep ontogenesis revisited: A longitudinal 24-hour home polygraphic study on 15 normal infants during the first two years of life. Sleep, 20(5), 323–333. https://doi.org/10.1093/sleep/20.5.323
28.
LovejoyM. C.GraczykP. A.O’HareE.NeumanG. (2000). Maternal depression and parenting behavior: A meta-analytic review. Clinical Psychology Review, 20(5), 561–592. https://doi.org/10.1016/S0272-7358(98)00100-7
29.
MasonG. M.KurdzielL. B. F.SpencerR. M. C. (2021). The memory benefits of two naps per day during infancy: A pilot investigation. Infant Behavior and Development, 65, 101647. https://doi.org/10.1016/j.infbeh.2021.101647
30.
MillerA. L.SeiferR.CrossinR.LebourgeoisM. K. (2015). Toddler’s self-regulation strategies in a challenge context are nap-dependent. Journal of Sleep Research, 24(3), 279–287. https://doi.org/10.1111/jsr.12260
31.
MindellJ. A.LiA. M.SadehA.KwonR.GohD. Y. T. (2015). Bedtime routines for young children: A dose-dependent association with sleep outcomes. Sleep, 38(5), 717–722. https://doi.org/10.5665/sleep.4662
32.
MindellJ. A.MooreM. (2018). Does sleep matter? Impact on development and functioning in infants. Pediatrics, 142(6), e20182589. https://doi.org/10.1542/peds.2018-2589
33.
MorganK.HayneH. (2011). Age-related changes in visual recognition memory during infancy and early childhood. Developmental Psychobiology, 53(2), 157–165. https://doi.org/10.1002/dev.20503
34.
NelsonC. A.ZeanahC. H.FoxN. A.MarshallP. J.SmykeA. T.GuthrieD. (2007). Cognitive recovery in socially deprived young children: The Bucharest Early Intervention Project. Science, 318(5858), 1937–1940. https://doi.org/10.1126/science.1143921
35.
PaavonenE. J.Saarenpää-HeikkiläO.Morales-MunozI.VirtaM.HäkäläN.PölkkiP.KylliäinenA.KarlssonH.PaunioT.KarlssonL. (2020). Normal sleep development in infants: Findings from two large birth cohorts. Sleep Medicine, 69, 145–154. https://doi.org/10.1016/j.sleep.2020.01.009
36.
ParfittY.AyersS. (2014). Transition to parenthood and mental health in first-time parents. Infant Mental Health Journal, 35(3), 263–273. https://doi.org/10.1002/imhj.21443
37.
RamosK. D.YoungclarkeD. M. (2006). Parenting advice books about child sleep: Cosleeping and crying it out. Sleep, 29(12), 1616–1623. https://doi.org/10.1093/sleep/29.12.1616
SchaefferP.AsnesA. G. (2018). What do pediatricians tell parents about bed-sharing?Maternal and Child Health Journal, 22(1), 51–58. https://doi.org/10.1007/s10995-017-2353-5
SeehagenS.CharltonS.StarkeyN.FallaizeA.BrownJ.JonesK. (2021a). The role of prior sleep for divergent thinking in infants. Journal of Sleep Research, e13457. https://doi.org/10.1111/jsr.13457
43.
SeehagenS.HerbertJ. S.ZmyjN. (2021b). Prior sleep timing and visual recognition of emotional faces in 6-month-old infants. Infant Behavior and Development, 65, 101655. https://doi.org/10.1016/j.infbeh.2021.101655
44.
SeehagenS.KonradC.HerbertJ. S.SchneiderS. (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. https://doi.org/10.1073/pnas.1414000112
45.
SeehagenS.ZmyjN.HerbertJ. S. (2019). Remembering in the context of internal states: The role of sleep for infant memory. Child Development Perspectives, 13(2), 110–115. https://doi.org/10.1111/cdep.12321
46.
StatonS. L.SmithS. S.PattinsonC. L.ThorpeK. J. (2015). Mandatory naptimes in child care and children’s nighttime sleep. Journal of Developmental & Behavioral Pediatrics, 36(4), 235–242. https://doi.org/10.1097/DBP.00000000000
00157
47.
StickgoldR.WalkerM. P. (2013). Sleep-dependent memory triage: Evolving generalization through selective processing. Nature Neuroscience, 16, 139–145. https://doi.org/10.1038/nn.3303
48.
TikotzkyL.SadehA.VolkovichE.ManberR.MeiriG.ShaharG. (2015). Infant sleep development from 3 to 6 months postpartum: Links with maternal sleep and paternal involvement. Monographs of the Society for Research in Child Development, 80(1), 107–124. https://doi.org/10.1111/mono.12147
WilliamsS.HorstJ. (2014). Goodnight book: Sleep consolidation improves word learning via storybooks. Frontiers in Psychology, 5, 184. https://doi.org/10.3389/fpsyg.2014.00184
52.
YooS.-S.GujarN.HuP.JoleszF. A.WalkerM. P. (2007a). The human emotional brain without sleep-A prefrontal amygdala disconnect. Current Biology, 17(20), R877–R878. https://doi.org/10.1016/j.cub.2007.08.007
53.
YooS.-S.HuP. T.GujarN.JoleszF. A.WalkerM. P. (2007b). A deficit in the ability to form new human memories without sleep. Nature Neuroscience, 10, 385. https://doi.org/10.1038/nn1851
54.
ZeanahC. H. (2009). The importance of early experiences: Clinical, research, and policy perspectives. Journal of Loss and Trauma, 14(4), 266–279. https://doi.org/10.1080/15325020903004426
