Sleep as a support for social competence, peer relations, and cognitive functioning in preschool children.

This article was downloaded by: [University of Colorado at Boulder Libraries] On: 28 December 2014, At: 07:13 Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

Behavioral Sleep Medicine Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/hbsm20

Sleep as a Support for Social Competence, Peer Relations, and Cognitive Functioning in Preschool Children a

a

a

Brian E. Vaughn , Lori Elmore-Staton , Nana Shin & Mona ElSheikh

a

a

Human Development & Family Studies, Auburn University Published online: 14 Feb 2014.

Click for updates To cite this article: Brian E. Vaughn , Lori Elmore-Staton , Nana Shin & Mona El-Sheikh (2014): Sleep as a Support for Social Competence, Peer Relations, and Cognitive Functioning in Preschool Children, Behavioral Sleep Medicine, DOI: 10.1080/15402002.2013.845778 To link to this article: http://dx.doi.org/10.1080/15402002.2013.845778

PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions

Downloaded by [University of Colorado at Boulder Libraries] at 07:13 28 December 2014

Behavioral Sleep Medicine, 12:1–15, 2014 Copyright © Taylor & Francis Group, LLC ISSN: 1540-2002 print/1540-2010 online DOI: 10.1080/15402002.2013.845778

Sleep as a Support for Social Competence, Peer Relations, and Cognitive Functioning in Preschool Children Brian E. Vaughn, Lori Elmore-Staton, Nana Shin, and Mona El-Sheikh Human Development & Family Studies Auburn University

Evidence that sleep influences social and cognitive adaptation for school-age children and adolescents is accumulating rapidly, but less research focuses on the role of sleep for adaptive functioning during early childhood. We addressed these questions using actigraphy to assess sleep duration, sleep quality, and variability in sleep schedules in relation to a range of social/emotional and cognitive measures, including receptive vocabulary, emotion understanding, peer acceptance, social skills, social engagement, and temperament. Children in a convenience sample (N D 62, 40 boys, mean age D 4.15 yrs, 67% European American) wore actigraphs for 4–7 days, with sleep and wake states determined using Sadeh’s scoring algorithm. Older children spent less time in bed at night and ethnic minority children (mostly African Americans) slept less at night and had lower sleep efficiency than did European American ethnic status children. Bivariate relations (controlling for sex, age, and ethnicity) between sleep variables and child adaptation scores showed that sleep duration was positively associated with peer acceptance, social skills, social engagement, receptive vocabulary, and understanding of the causes of emotions. Fewer variables were associated with nighttime sleep quality and variability and these tended to be related to outcome variables suggestive of behavioral and emotional regulation. Results suggest that sleep parameters are broadly implicated in the adjustment of preschool age children.

That sleep is a critically salient biological state of infancy and childhood is evident from the fact that children spend half (or more) of their lives sleeping through early childhood (e.g., Jenni, Molinari, Caflisch, & Largo, 2007) and are still sleeping for about eight hours/day in adolescence and adulthood (Iglowstein, Jenni, Molinari, & Largo, 2003). Central nervous system development is intimately intertwined with the duration and quality of sleep (e.g., Walker & Stickgold, 2006); furthermore, sleep insufficiency and poor sleep quality predict This work was completed while all authors were employed at Auburn University. Lori Elmore-Staton is now employed at Mississippi State University, School of Human Sciences. Nana Shin is now employed at Ewha Womans University, Department of Child Development, Seoul, South Korea. Correspondence should be directed to Brian E. Vaughn, Human Development & Family Studies, 203 Spidle Hall, Auburn University, Auburn, AL 36849. E-mail: [email protected]

1


2

VAUGHN, ELMORE-STATON, SHIN, EL-SHEIKH

problems in daytime functioning for school-age children, including mood, quality of social behavior, and school performance (e.g., Sadeh, 2007). Although studies linking sleep with child outcomes in nonclinical samples have increased in the last decade, the normative course of sleep development and the outcomes associated with normal individual differences in sleep patterns are not well documented. Moreover, in comparison with the sleep literatures covering the infancy and school age periods, the sparseness of research coverage for early childhood is noteworthy and potentially very important because the ecology of early childhood has undergone substantial change in recent decades. That is, the majority of preschool age children (i.e., nominally, 36–66 months of age) are no longer receiving the bulk of their daytime care from a biological parent but rather are cared for in some form of group care (Aud et al., 2012). Our purpose, therefore, is to explore aspects of young children’s sleep including measures of sleep duration, sleep quality (e.g., sleep efficiency, nighttime activity), and night-to-night variability in sleep schedules as these relate to aspects of social/emotional and cognitive adaptation for children receiving care in an early education center. Empirical studies with both infants and school-age children support the role of sleep for normal adaptive functioning across cognitive (e.g., Bernier, Carlson, Bordeleau, & Carrier, 2010; Buckhalt, El-Sheikh, Keller, & Kelly, 2009; see Dewald, Meijer, Oort, Kerkhof, & Bögels, 2010 for a recent review and meta-analyses) and socioemotional functioning domains (e.g., Chorney, Detweiler, Morris, & Kuhn, 2008; El-Sheikh, Kelly, Buckhalt, & Hinnant, 2010; and see Astill, Van der Heijden, Van IJzendoorn, & Van Someren, 2012, for a meta-analysis). These studies suggest that normative differences in sleep duration and quality are associated with a range of differences in adaptive functioning for school-age children. Lemola et al. (2011) reported that sleep duration and latency to fall asleep after going to bed both were associated (positively with sleep duration, negatively with poor sleep quality) with trait optimism, selfesteem, and social competence in school-age children. Conversely, school-age children who sleep less and/or whose sleep is disrupted (e.g., by frequent night waking) are reported to have elevated levels of emotional problems, peer problems, hyperactivity, and other social difficulties when compared to peers sleeping longer each night without disruptions (Waiter et al., 2005). Additional research in cross-sectional and longitudinal samples has linked sleep duration and sleep quality with aspects of emotion and aggressive behavior in school-age children (e.g., Chervin, Dillion, Archbold, & Ruzicka, 2003; Goodnight, Bates, Staples, Pettit, & Dodge, 2007). In their meta-analysis of studies of sleep and problem behaviors, Astill et al. (2012) concluded that sleep problems are consistently associated with both externalizing and internalizing problem behaviors, and longitudinal studies suggest that sleep durations during infancy and early childhood predict elevated levels of hyperactive/impulsive behaviors at school entry (e.g., Couchette et al., 2007). Sleep duration and quality also influence cognitive and academic functioning for school-age children. Sadeh, Gruber, and Raviv (2002) found that reaction times for information processing tasks were negatively associated with sleep duration (i.e., shorter response latencies when children slept longer) and positively associated with sleep disruption measures (i.e., more errors as night waking episodes increased). Steenari et al. (2003) also reported that poorer sleep quality was associated with incorrect responses on working memory tasks, even after controlling for the effects of age, and El-Sheikh, Buckhalt, Cummings, and Keller (2007) found that aspects of sleep quality, from both self-reports and actigraphy measures, were associated with school-age children’s tests of academic achievement.


SLEEP AS A SUPPORT FOR SOCIAL COMPETENCE

3

Although some studies have included younger children in their samples, very few examined the data for preschool-age children separately from older participants. A few studies have focused exclusively on healthy (i.e., without diagnosed sleep problems or other clinical health problem) preschool-age children and some of these have examined sleep during early childhood as a correlate of adaptive social and cognitive functioning outside of the family context. Bates, Viken, Alexander, Beyers, and Stockton (2002) found that sleep disruptions (indexed in their study by measures of night sleep and bedtime variability reported by mothers) were negative correlates of teachers’ ratings of child adjustment and positive correlates of their ratings of problem behaviors. Komada et al. (2011) also reported that Japanese mothers’ reports (1,746 children between 2 and 5 years of age) of greater variability in bedtimes were associated with externalizing problem behaviors (also reported by mothers). Although the relevant studies for preschool children are few, findings suggest that results reported for school-age children and adolescents are also present in samples of younger children. Studies of cognitive/academic outcomes for healthy preschool children are also sparse. In a study of 3- to 5-year-olds attending full-day child care (N D 59, 58% African-American), Lam, Mahone, Mason, and Scharf (2011) found that nighttime sleep duration was a positive, significant correlate of receptive vocabulary, but that daytime sleep duration (i.e., naps) was negatively associated with performance on cognitive tests. Jung, Molfese, Beswick, JacobiVessels, and Molnar (2009) found that parent reports of sleep duration, but not sleep problems, predicted scores for General Conceptual Ability (from subscales of the Differential Ability Scales; Elliot, 1990) in a sample of 67 preschool children tested annually over three consecutive years in program (from age 3 through age 5). Karpinski, Scullin, and Montgomery-Downs (2008) found that parent-reported sleep-disordered breathing negatively predicted executive function indicators (i.e., planning, inhibition, working memory) in a sample of 39 children (mean age 52 months, 90% European/American) assessed using standard laboratory tasks. Bernier, Beauchamp, Buvette-Turcot, Carlson, and Carrier (2013) also found sleep effects on executive function indicators, in a longitudinal study linking infant sleep to cognitive assessments at age 4. Taken together, relations between sleep duration, quality, and variability and a range of social/emotional and cognitive outcomes in early childhood are comparable to findings reported for older children and adolescents. Nevertheless, studies of sleep during early childhood remain sparse and most results have not been replicated. Moreover, very few studies have examined outcomes based on directly observed child behavior in preschool classrooms and none that we could find reported results that controlled for potential effects of age, ethnic status, and sex. These are serious lacunae in the database because most preschool-age children are spending the bulk of their waking hours in some form of center-based care and it is in this context that they are acquiring the behaviors, attitudes, values, and goals that together constitute social competence with peers (Vaughn et al., 2009; Waters & Sroufe, 1983). Because sleep patterns begin to stabilize during early childhood as well, it is important to determine the nature of relations between sleep and the social/emotional processes characteristic of socially competent preschool children. Finally, in many published studies, parent reports are the primary sources for both the assessment of sleep variables and the outcomes associated with those variables, raising questions about mono-informant effects. Very few studies have assessed sleep using objective measures (e.g., actigraphy) to supplement (or supplant) parent reports and some of those studies have


4


failed to find significant associations between actigraphy-based sleep parameters and parent reports on outcome measures (e.g., Goodlin-Jones, Tank, Liu, & Anders, 2009). Finally, no single study has attempted to relate sleep parameters to a broad range of social/emotional and cognitive outcomes for a sample attending full-day programs. Our analyses address these issues. The study takes advantage of an ongoing, comprehensive study of social/emotional and cognitive adaptation in a sample of children from middleclass families attending a model early childhood education center accredited by the National Association for the Education of Young Children. Children generally enter the study as 3year-olds and data collection ends when they graduate to public or private schools after their fifth birthday. The sample is ethnically mixed, suggesting that any potential ethnic differences should not be confounded by SES differences, and more than 90% of age-eligible children in the center have participated in the larger study. Social/emotional assessments include observations and interviews that yield indicators of peer social competence as well as teachers’ ratings of temperamental attributes that have been collected since the inception of the study (October 1, 2000). An emotion knowledge assessment was initiated in the fifth year of data collection (Denham & Couchod, 1990), and tests of receptive vocabulary (i.e., Peabody Picture Vocabulary Test IV, Dunn & Dunn, 2007) and behavioral self-control (i.e., Head to Toes Task, Ponitz et al., 2008) were added in the sixth year for subsets of children in the annual waves of data collection. Sleep data were collected for about 33% of participating children in the seventh and eighth years of the study. Because the sample is nonclinical, we focused on the positive correlates of sleep as well as on suboptimal or dysfunctional outcomes associated with normative sleep problems. We anticipated that children with longer sleep durations, better sleep quality, and less night-to-night variability in bedtimes and wake times would be advantaged across the range of adaptation domains assessed relative to peers with less optimal sleep. METHOD Participants Sixty-two 3–5-year-old children from the larger study (Table 1 displays demographic information) provided data for this report. Participants attended a university-managed early education TABLE 1 Demographic Information

Child Characteristics Age Ethnicity European American African American Others Sex Boys Girls

Frequency (N)

Percent (%)

Mean (SD)

—

—

4.15 (.62)

41 18 3

66 29 5

— — —

40 22

65 35

— —



5

center located in a metropolitan area in the Southeastern United States. This National Association for the Education of Young Children (NAEYC) accredited child care center was created as a partnership among the city, some of its major enterprises, and a public university. Families enrolling children at this center are middle-class by the standards of the local community (e.g., more than 90% of parents have university level degrees, and the majority work in professions requiring postgraduate training). The center provides full-day care and education services for children ages six weeks to five years. Participants in the larger study were enrolled in seven classrooms (each data collection year) that contained children between 3 and 5 years of age at the beginning of the academic year (between 110 and 120 in each academic year, with approximately half being older children who had attended the center in the previous academic year). All children included in our analyses spent 6–9 hours each weekday in the center. Children included in the present sample did not differ significantly from children not included for any of the outcome variables reported in the Results section. Procedures Sleep data collection was embedded in the larger project described above. Different teams of observers and interviewers were responsible for each aspect of data collection. For this report, in addition to measures of sleep, we selected indicators of positive social/emotional adaptation in the classroom and measures of cognitive functioning. We also included measures indicative of poorer classroom adaptation and behavioral reactivity (e.g., negative sociometric nominations, initiated negative interactions, behavioral reactivity and regulation) that prior studies (see Astill et al., 2012) suggest are related to sleep disturbances or insufficiencies. All protocols for the study, including the sleep assessments, were approved by the appropriate Institutional Review Board prior to participant recruitment. Classroom observation, child interviews, and teacher evaluations of child behavior were typically initiated in October of the academic year and continued until children in all participating classrooms had been assessed (typically by April). Sleep assessments were obtained between November and May (with a break between midDecember and the end of January) and were scheduled so as to occur within ˙ one month of classroom data collections. Sleep assessments. For the sleep assessments, letters describing the study aims and procedures and requesting consent from parents were distributed in all classrooms with children of age three years and older. The overall rate of participation across classrooms was 36% (5 children per classroom). All families consenting to their child’s participation received $100 compensation for their time and effort. The actigraph (Ambulatory Monitoring Motionlogger) was placed on the child’s nondominant wrist by a researcher. Parents were instructed to allow the child to wear the watch continuously for 7 consecutive days (i.e., 1 week), except during baths or water play. Children who wore the watch for fewer than 4 weekday nights were not included in this sample. During sleep data collection, parents kept a diary of their child’s sleep pattern and recorded sleep-wake times; the latter were used to corroborate actigraphy recordings (83% of families returned complete sleep diary information). For the 11 children whose parents did not return completed sleep diaries, an expert in actigraphy scoring, who also coded all actigraphy data for the study, decided on sleep onset and offset times. Due to the 24-hour activity assessment and


6


the age of the participants, a clear distinction could be made between sleep and wake states; no cases were missing due to the absence of sleep logs. Sleep parameters were averaged over the nights that the actigraph was worn. For this report, actigraph indices of sleep duration were (a) duration of bedtime (i.e., time in minutes from first epoch scored as sleep to end of last epoch scored as sleep) and (b) total minutes of sleep (i.e., duration of bedtime less all waking intervals during the night). Actigraph indices of sleep quality included (a) sleep efficiency (% of minutes scored as sleep compared to overall time spent in bed), (b) the overall activity index (% of epochs with greater than 0 activity score), and (c) sleep latency (number of minutes from first activity count below 100 to sleep onset). Sleep onset and morning wake time variability were scored as the standard deviations for these parameters over the days that the child wore the actigraph. Classroom assessments. Peer acceptance was assessed using two sociometric tasks. Trained assistants administered a nomination picture-sociometric (McCandless & Marshall, 1957) and a paired-comparisons picture-sociometric task (Vaughn & Waters, 1981). Head and torso photographs of participating children were prepared for each sociometric measure. Care was taken to ensure the child knew the names of each classmate before administering the tasks. The nomination task was administered first and both were completed in a quiet area outside the child’s classroom to minimize distractions. Following standard conventions for sociometric data, scores were standardized within classroom prior to analysis. For sociometric nominations, positive and negative choices were elicited. Each child was presented with an array (randomly mixed for each child) of photographs of his/her classmates. From this array, each child chose three peers whom he or she especially liked and three whom he or she did not especially like. Positive and negative scores were calculated as the total number of times a child was chosen by peers both positively and negatively. Totals were averaged across all children making nominations in each class. For the paired-comparisons task, children viewed each pair of children on a laptop computer and made a choice concerning, “Which of these two children do you especially like?” (i.e., number of pairs judged D N .N 1/=2 for each classroom). The researcher administering the task monitored the child’s apparent interest and stopped the session if the child became distracted. Most children completed the task in a single 15–20-minute session and none took more than two sessions. The average score was calculated as the sum of choices received from peers divided by the number of peers making choices. The standardized scores for the nomination and paired-comparison tasks were significantly correlated .r D :46/ and these were averaged to create a composite “Peer Acceptance” score. We also retained the negative nominations sociometric score (also standardized within classroom) as a potential sleep variable correlate. The California Child Q-sort (CCQ, Block & Block, 1980) was used to characterize the profile of behaviors, personality attributes, and attitudes of all participating children from the larger study. Q-sort observers worked in teams of two for each classroom. Each observer spent approximately 20 hours observing all children participating in the larger study in a given classroom and taking notes on the behaviors and attributes of individual children over this period. Each child was observed on several different days across a variety of activity settings (e.g., meal times, small groups, indoor and outdoor free play, transitions such as standing in lines, cleanup, etc.). After completing the observations, each observer described all



7

participating children using the CCQ items. Prior to data collection, all observers were trained in the meanings of the items and instructed regarding items whose content they were not likely to observe (such items were placed in the center of the Q-sort). The items were sorted into a rectangular distribution with equal numbers of items (9 piles of 11, with the 100th item placed in the center category). In the larger study, cross-observer Q-correlations (i.e., complete sort for observer 1 complete sort for observer 2) ranged from .40 to .95 across children with a median of .66. Sorts were averaged across observers for each item prior to calculating the final profile scores. Two summary scores were derived: (a) Ego-undercontrol, and (b) Egoresiliency (see Block & Block, 1980). These were computed by correlating the aggregated Q-sort profile for a given child with “criterion profiles” of the hypothetical child at the extreme pole of the undercontrol and the resiliency dimensions that had been generated from sorts by experts in preschool children’s behavior who shared a common interpretation of the two constructs (Block & Block, 1980). These personality dimensions reflect the child’s characteristic degree of activity/reactivity (Ego-undercontrol) and the capacity to shift the characteristic level of reactivity in response to environmental demands (Ego-resiliency). Cross-rater agreement (intra-class correlations) for the two years of data collection being reported here were .82 and .83, respectively. The two construct scores were standardized within classroom. Interaction and visual regard observation protocols follow the procedures described by Vaughn and associates (Shin et al., 2011a; Vaughn et al., 2009), who validated the derived scores as indicators of child social competence. Together, these are indicators of a social competence factor labeled “Social Engagement/Motivation.” Observations of initiated interaction and visual attention given to peers (collected by assistants who were not involved in Q-sort observations) are indicators for this dimension. These were collected throughout the preschool day, with the constraint that observations were not initiated unless at least half of the children enrolled in the class were present. Observers were trained to use the interaction and visual attention codes and reached percent agreement levels of 80% or higher (kappas > .67) with their co-observers prior to formal data collection. Two observers collected these data in each classroom. For initiated interaction, observers worked from class rosters and watched each participating child in class on a given day for a 15-s interval. At the end of the interval, the assistant recorded identifiers for all children with whom the target child interacted, a separate code identified the initiator of the interaction, and a third code indicated whether the overall tone of the interactive episode had been emotionally positive, negative, or neutral. A completed class roster (for all children present on a given day) constituted a “round” of the class. Each observer completed 10–25 observation rounds of the class each observation day. Approximately 200 rounds of observation were completed in each classroom (100 by each observer). All social contact was coded as an interaction, even when the contact was casual and may not have elicited a response from the recipient (e.g., a child standing in line briefly puts her hands on the shoulders of the child in front of her). To be coded as a positive initiation, some indicator of positive affect (e.g., smile, laugh) had to be observed in one or both interactants and no indicators of negative affect (anger, rejecting a suggestion, aggressive behavior) in either partner could be present. To be coded as a negative initiation, one or both interactants had to be observed displaying anger, fussing, crying, or forcibly rejecting a suggestion or offer. Interactions in which a simple refusal (e.g., to play with, to give up a toy) was observed were not coded as negative initiations, unless one or both children also displayed anger, fussing, and so forth. All other interactions were coded as neutral. To adjust for differences in numbers of


8


absences from the classroom during observation periods, interaction codes were converted to rates by dividing a child’s total score by the number of observation rounds for which she/he was present in the classroom. The rate scores were standardized within classroom. Two children who were absent for more than 50% of observation rounds were not included in analyses of the interaction data reported here. Rounds of visual regard observation were interspersed with the interaction observations (usually 5 interaction rounds, 5 visual regard rounds, etc.). Working from class rosters, an observer watched a target child for 6 s and then recorded identifiers for peers to whom the target directed visual regard. A given child was observed for each round of the class when his/her name appeared on the class roster, and no child was observed twice in a single round before all children present were observed once. Again, approximately 200 observation rounds were collected in every classroom. The final score for a child was the sum of looks and glances received from peers (see Vaughn & Waters, 1981). Rate scores were calculated by dividing the total score for a given child by the number of observation rounds for which that child was present, to adjust for absences. Rate scores were standardized within classroom. Vaughn et al. (2009) have reported that positive and neutral initiated interaction scores and the visual attention received score are significantly associated and load together on a single factor. Consequently, we averaged the three standardized scores to create a “Social Engagement/Motivation” composite score. As noted above, initiated negative interactions were also coded. We calculated (and standardized within classroom) an initiated negative interaction score and retained it as a possible correlate of the sleep variables. Three measures relevant to cognitive development, emotions, and self-regulation were administered individually: (a) the PPVT-IV (Dunn & Dunn, 2007); (b) a modified version of Denham’s emotion knowledge tasks (e.g., Denham & Couchoud, 1990) that used facial photos of emotion states; and (c) the Head to Toes task, a widely used procedure to assess aspects of children’s effortful control capacity (Ponitz et al., 2008). The PPVT-IV was administered in a quiet area away from the classroom by an experienced examiner. The age-adjusted standard score served as our receptive vocabulary indicator. A trained researcher administered the emotion knowledge tasks in a laboratory room located in the child care center. The child was shown photos representing discrete emotions and first asked to name the emotion states shown. Then the child was given the emotion label and asked to point to the appropriate photo. Finally, the child was asked to provide a rationale for why the pictured child in the photo would feel the expressed emotion. Scores were the number of correct responses in each phase of the task. We used the third question (i.e., rationale) as our indicator of emotion knowledge because it requires the child to reason about the emotion state depicted rather than simply recall an emotion label. The Head to Toes task was also administered in the laboratory room on a different day than either of the other two assessments. The child was first told to touch his or her head when the examiner said to “touch your head,” and then to touch feet when the examiner said, “Touch your feet.” No child failed to respond correctly. Next, the experimenter told the child to act in the opposite manner when told to “touch your feet/head” (i.e., if told to “’touch your head,” the child should touch feet and vice versa). The child repeated the instruction (if told to touch the head, touch my toes). Four practice trials were administered to provide training, and corrective feedback was given if the child did not act in accord with the new instruction. Then 10 test trials were administered without feedback. Scores were the number of spontaneous correct responses



9

on the test trials (i.e., without corrective feedback). A separate score for “self-corrected” trials (i.e., trials in which the child started to make an incorrect response, but changed to the correct response without experimenter feedback), for both practice and test trials, was also included as an outcome variable. Consistent with Ponitz et al. (2008), performance on the practice and test portions of the task was significantly correlated with age in this sample and 11 younger children failed every test trial (mean ages 3.8 years vs. 4.2 years, for children successfully performing on at least one trial). As part of the larger project, teachers rated children’s behavior using scales from the Child Behavior Questionnaire (Rothbart, Ahadi, Hershey, & Fisher, 2001). We used the Attention Focusing scale as an indicator of effortful control, a summary construct described by Rothbart et al. that has been used as an indicator of regulatory capacity in previous studies of preschool children (e.g., Fabes et al., 1999). Together, these assessments broadly describe social/emotional and cognitive functioning during early childhood. We expected that sleep parameters reflecting the duration of nighttime sleep, sleep quality, and less variability in sleep onset and wakeup times would be associated with more optimal levels of adaptive functioning across these measures. RESULTS Preliminary Analyses We first examined distributions of the nighttime sleep variables to identify outliers (i.e., cases with scores greater than 3.5 SDs from the means, which may indicate a malfunction on the actigraphy watch). One case had outlier values on overall sleep minutes, sleep efficiency, and sleep activity. This case was excluded from subsequent analyses (final N D 61). Table 2 presents the associations among the sleep variables. Because both sleep duration indicators were highly correlated .r D :77/, we created a composite score to reduce the number of subsequent tests conducted. Sleep efficiency and the sleep activity index were also highly correlated .r D :77/ and a composite was created (after reverse scoring the activity index). The two sleep variability indicators were not significantly correlated and sleep onset variability TABLE 2 Correlations Among Nighttime Sleep Variables (Averages Over All Nights; N D 61) Sleep Variables Bedtime Duration Min. Total Sleep Minutes Sleep Efficiency Sleep Activity Index Sleep Latency Minutes Variability Sleep Onset Variability Wake Time Mean

— .77*** .19 .05 .09 .16 .01 537

— .77*** .47*** .27* .11 .25 468

— .77*** .47*** .10 .25 87%

— .44*** .17 .26* 46

— .08 .14 10

Note. Means rounded to nearest whole number, except for sleep onset and wake variability means. *p < :05; ***p < :001.

— .01 .04

— .06


10


was not a significant correlate of the other sleep variables. Consequently, we only retained the wake time variability score for subsequent analyses. Thus, four sleep variables were used to test relations with social/emotional and cognitive adaptation variables. We then examined potential associations between demographic status variables (sex, age, ethnicity) and both the sleep and outcome variable sets. ANOVAs were calculated using sex and ethnicity as IVs and age as a covariate. Only one ANOVA revealed a single main effect. European American (EA) children had higher scores for the composite nighttime sleep duration variable than other ethnic status children, F .1; 55/ D 25:29, p < :001. No other main effects were significant and no interactions were significant in any analysis. ANOVAs for the outcome variable set revealed significant effects of age for the PPVT standard score, the emotion cause score, and the test trials score for the Head to Toes task. Older children achieved higher scores for emotion cause and Head to Toes tasks, but had lower PPVT standard scores. A significant main effect of ethnic status was found for Peer Acceptance, emotion cause, and Ego-resilience. All differences favored EA children. Nonsignificant trends (i.e., p < :10) for ethnic status also favoring EA children were observed for the PPVT score. No main effects of sex reached significance, but trends were observed for the Social Engagement composite, test trials on the Head to Toes task, the Ego-undercontrol, and negative sociometric nominations. Girls had lower scores on all of these variables excepting the Head to Toes test trials. These results justify our inclusion of sex, ethnicity, and age as control variables in the analyses of relations between the sleep and outcome variable sets.

Sleep and Adaptive Functioning Partial correlations (controlling for age, ethnic status, and sex) between the four sleep parameters and the adaptive functioning variables taken from the larger study are presented in Table 3 (outlier removed). The sleep duration composite had significant correlations with the

TABLE 3 Partial Correlations between Sleep Parameters and Adaptive Functioning Variables (Age, Sex, and Ethnicity Controlled) Night Sleep Duration Peer Acceptance Social Engagement Ego Resiliency Ego-undercontrol Initiated Negative Interaction Negative Nominations PPVT-IV standard score Emotion Cause Head to Toes: Test Head to Toes: Self-correct CBQ Attention Focus (teacher) ap

< :10; *p < :05; **p < :01.

.33** .28* .27* .10 .01 .08 .45** .39** .09 .29* .19

Night Sleep Efficiency/Activity .15 .11 .09 .25a .31* .10 .06 .10 .09 .00 .06

Night Sleep Latency .11 .17 .14 .05 .21 .28* .18 .02 .12 .03 .25a

Variability Wake Onset .05 .24 .22 .28* .28* .03 .01 .15 .01 .33** .05



11

PPVT standard score, the emotion cause score, the Peer Acceptance and Social Engagement composites, Ego-resilience, and the Head to Toes self-correction score. The sleep quality composite was significantly associated with initiation of negative interactions and had a trendlevel association with Ego-undercontrol (both signed negatively). Sleep latency was significantly associated with negative sociometric nominations (signed negatively) and had a trend-level association with temperamental Attention Focusing (signed positively). Waking variability was associated with initiating negative interactions, Ego-undercontrol, and the self-correction score on the Head to Toes task, all signed positively. Because demographic status variables had significant associations with several of the classroom adaptation variables, we probed for potential moderating effects of sex and/or ethnic status for those outcome variables significantly associated with demographic indicators in preliminary analyses, using hierarchical regression models. Age was included as a covariate in these regressions and was entered at the initial step in each analysis. The sleep variables were centered prior to analysis and interaction terms were created to test for moderation effects. Six regressions were computed for interactions with ethnicity and four were computed to test for interactions with sex. In no analysis was the interaction term significant, suggesting that relations between sleep and outcome variables are not moderated by either ethnicity or sex.

DISCUSSION Researchers have documented that parameters of sleep are fundamental supports for adaptive social and cognitive functioning for school-age children, adolescents, and adults (e.g., Walker, 2009). Our primary goal was to determine the extent to which implications of sleep were equally broad for preschool-age children. The results suggest that sleep during early childhood is associated with a range of social, emotional, cognitive, and regulatory aspects of adaptation and that these results are little affected by age, ethnicity, and sex, even though these demographic variables are also associated with both sleep and outcome variables. Overall, our findings suggest that more optimal sleep supports preschool children’s adaptive functioning, as it does during other age periods. However, we also observed that sleep duration, quality, and variability supported different domains of adaptation. Of the three sleep aspects, duration seems the most implicative across multiple domains of functioning. Sleep duration measures had significant associations with two classroom social competence composites (i.e., Peer Acceptance, Social Engagement/Motivation) and Ego-resiliency, with intellectual functioning (PPVT vocabulary scores, knowledge of emotion causes), and with self-correction in the Head to Toes task. Sleep quality and variability had fewer significant associations with adaptive functioning variables than was true for sleep duration. Sleep quality variables were significant, negative correlates of initiating negatively toned interactions with peers and of negative nominations on the sociometric task, although different sleep quality variables were associated with each of the two outcome variables. Variability in wake time was a positive correlate of both Ego-undercontrol and initiating negative interactions, and this variable was also a positive correlate of self-correction responses in the Head to Toes task. The number of significant associations with sleep quality and sleep variability is modest; however, the variables for which significant associations were observed converge with previous


12


reports that have focused on sleep quality and variability. For example, Bates et al. (2002) reported that sleep variability was associated with teacher reports of problem behaviors, which is consistent with our findings for initiating negative interactions and Ego-undercontrol (i.e., reactivity). Even the seemingly anomalous association with self-correction in the Head to Toes task is consistent with a pattern of acting before thinking, which reflects the undercontrol of impulse implied by our reactivity measure. Our finding that sleep duration was positively correlated with social and cognitive competence replicates results reported in prior studies for school-age and preschool children. For example, Lemola et al. (2011) found significant associations between sleep duration and measures of social competence, self-esteem, and optimism. In our data, sleep duration was a positive correlate of Peer Acceptance and Social Engagement/Motivation, two aspects of peer social competence (Vaughn et al., 2009) and Ego-resiliency, which is defined by Block and Block (1980) in a way that implies emotional and behavioral regulation. Our finding that nighttime sleep duration is positively associated with receptive vocabulary (i.e., PPVT-IV standard scores) reproduces results reported by Lam et al. (2011), who also used the PPVT to index receptive vocabulary, and we found that sleep duration was also a positive correlate of reasoning about emotion states. We considered this emotion knowledge score as a “cognitive” emotion variable and it is not surprising that it was associated with the PPVT standard score (age, sex, and ethnicity controlled, partial r D :44). However, a post hoc regression testing whether sleep duration might mediate this relation suggested that both were unique predictors of child emotion knowledge. Taken together, our findings suggest that preschool children show most of the same kinds of strengths and vulnerabilities in relation to sleep that are found for older children and adolescents. Continuities of effects across age periods notwithstanding, we note that sleep quality variables had fewer significant associations with variables from our outcome domains than did the sleep duration composite. This is noteworthy because studies of older children more frequently highlight sleep quality as a correlate or predictor of adaptive functioning (e.g., Buckhalt et al., 2009; El-Sheikh et al., 2007; Steenari et al., 2003). Our study was not intended to replicate prior studies and it differs in many ways from studies of school-age children (e.g., we did not gather family functioning data and did not test for academic achievement as in the Buckhalt and ElSheikh reports). Moreover, sleep quality variables (but not sleep duration) were associated with a measure of attachment security in a subset of the children from the present study (Vaughn et al., 2011). Future sleep research with preschool children should include measures of family relationships and family functioning in order to test more complex interactive relations (e.g., Buckhalt et al., 2009; El-Sheikh, 2011). It would also be informative to conduct such research longitudinally to determine when and how individual differences in sleep parameters contribute to child functioning and how sleep parameters interact with other social and psychobiological parameters to influence the quality of adaptation during early childhood. There are also limitations to our study that may constrain the generality of our results. First, these data were collected in a moderately sized, middle-class sample and children were attending a model early childhood education program. However, this sample constraint might be expected to reduce the effect sizes of associations and we detected several significant associations that replicate results reported elsewhere. If our results were, in fact, influenced by the sample, we would expect larger effect sizes in a sample more diverse with respect



13

to socioeconomic status and program quality. Second, we do not report on daytime sleep parameters in this report. This decision was prompted by two considerations. Lam et al. (2012) reported negative associations between daytime nap duration and PPVT scores, although nighttime sleep duration was a positive predictor of the PPVT scores, which suggests that daytime naps may serve different functions than nighttime sleep for preschool children. Furthermore, a post hoc analysis of night and daytime duration scores for our dataset indicated a nonsignificant association between them (rs D :004, .06, for overall duration and overall sleep minutes, respectively). Thus, children with longer nighttime sleep durations did not necessarily sleep for more or fewer minutes in daytime naps. Additional post hoc analyses revealed that naptime sleep had nearly chance level associations with the outcome battery. Combining these nighttime and naptime variables could only have diluted effects of the nighttime duration variables and might have obscured meaningful relations between sleep and outcome variables. Finally, this is a cross-sectional study and directionality of effects for model variables cannot be determined. Despite these limitations, our findings suggest that nighttime sleep is an important support for good-quality daytime functioning for healthy preschool children in full-day child care. Whereas most research on sleep during early childhood has used clinical (i.e., diagnosed sleep problem) samples and parent reports of sleep duration, quality, and/or variability, our findings come from a sample of low-risk, nonclinical participants in which sleep was measured objectively using actigraphy. Individual differences for sleep parameters are mostly within the expected, “normal” ranges; nevertheless, we found that longer nighttime sleep with fewer disruptions and with less variability for wake-up times are associated with more optimal social and cognitive functioning during early childhood. Our findings suggest that normative sleep problems impact children’s adaptive functioning in group care settings and they justify more detailed and longitudinal studies of sleep in young children to determine whether sleep insufficiency and/or sleep fragmentation interferes with cognitive and emotional processes in the same manner that these effects have been demonstrated in adults (e.g., Banks, Eddy, Agstadt, Nathan, & Phan, 2007; Jones & Harrison, 2001; Randazzo, Muehlbach, Schweitzer, & Walsh, 1998). Finally, because our findings will inform decision making about sleep schedules for young children, they should be brought to the attention of parents and childcare providers.

FUNDING This research has been supported in part by National Science Foundation grants BCS 06-23019 and BCS 08-43919, by an Alabama Agricultural Experiment Station/Lindsey Foundation grant ALA080-049, and by Hatch Project #ALA042-1-09042.

ACKNOWLEDGMENTS The authors thank the directors, teachers, and parents from the Harris Early Learning Center in Birmingham, Alabama, for their support and cooperation with this research program. We also thank Lisa Krzysik and Bridget Wingo for their assistance with data collection and actigraphy.

14



REFERENCES Astill, R. G., Van der Heijden, K. B., Van IJzendoorn, M. H., & Van Someren, E. J. W. (2012). Sleep, cognition, and behavioral problems in school-age children: A century of research meta-analyzed. Psychological Bulletin, 138, 1109–1138. Aud, S., Hussar, W., Johnson, F., Kena, G., Roth, E., Manning, E., : : : Zhang, J. (2012). The condition of education 2012 (NCES 2012-045). Retrieved from U.S. Department of Education, National Center for Education Statistics: http://nces.ed.gov/pubsearch. Banks, S. J., Eddy, K. T., Angstadt, M., Nathan, P. J., & Phan, K. L. (2007). Amygdala-frontal connectivity during emotion regulation. Social Cognitive and Affective Neuroscience, 2, 303–312. Bates, J. E., Viken, R. J., Alexander, D. B., Beyers, J., & Stockton, L. (2002). Sleep and adjustment in preschool children: Sleep diary reports by mothers relate to behavior reports by teachers. Child Development, 73, 62–74. Bernier, A., Beauchamp, M. H., Buvette-Turcot, A.-A., Carlson, S., & Carrier, J. (2013). Sleep and cognition in preschool years: Specific links to executive functioning. Child Development, 84, 1542–1553. Bernier, A., Carlson, S. M., Bordeleau, S., & Carrier, J. (2010). Relations between physiological and cognitive regulatory systems: Infant sleep regulation and subsequent cognitive functioning. Child Development, 81, 1739– 1752. Block, J. H., & Block, J. (1980). The role of ego-control and ego-resiliency in the organization of behavior. In W. A. Collins (Ed.), Development of cognition, affect, and social relations (Minnesota Symposium on Child Psychology) (Vol. 13, pp. 39–101). Hillsdale, NJ: Erlbaum. Buckhalt, J. A., El-Sheikh, M., Keller, P. S., & Kelly, R. J. (2009). Concurrent and longitudinal relationships between children’s sleep and cognitive functioning: The moderating role of parent education. Child Development, 80, 875– 892. Chervin, R. D., Dillon, J. E., Archbold, K. H., & Ruzicka, D. L. (2003). Conduct problems and symptoms of sleep disorders in children. Journal of the American Academy of Child and Adolescent Psychiatry, 42, 201–208. Chorney, D. B., Detweiler, M. F., Morris, T. L., & Kuhn, B. R. (2008). The interplay of sleep disturbance, anxiety, and depression in children. Journal of Pediatric Psychology, 33, 339–348. Denham, S. A., & Couchoud, E. A. (1990). Young preschoolers’ understanding of emotions. Child Study Journal, 20, 171–192. Dewald, J. F., Meijer, A. M., Oort, F. J., Kerkhof, G. A. M., & Bögels, S. M. (2010). The influence of sleep quality, sleep duration and sleepiness on school performance in children and adolescents: A meta-analytic review. Sleep Medicine Reviews, 14, 179–189. Dunn, L. M., & Dunn, D. M. (2007). Peabody Picture Vocabulary Test (4th ed.). Minneapolis, MN: NCS Pearson. El-Sheikh, M. (Ed). (2011). Sleep and development: Familial and socio-cultural considerations. New York, NY: Oxford University Press. El-Sheikh, M., Buckhalt, J., Cummings, E. M., & Keller, P. (2007). Sleep disruptions and emotional insecurity are pathways of risk for children. Journal of Child Psychology and Psychiatry, 48, 88–96. El-Sheikh, M., Kelly, R. J., Buckhalt, J. A., & Hinnant, J. B. (2010). Children’s sleep and adjustment over time: The role of socioeconomic context. Child Development, 81, 870–883. Fabes, R. A., Eisenberg, N., Jones, S., Smith, M., Guthrie, I., Poulin, R., : : : Friedman, J. (1999). Regulation, emotionality, and preschoolers’ socially competent interactions. Child Development, 70, 432–442. Goodlin-Jones, B., Tang, K., Liu, J., & Anders, T. F. (2009). Sleep problems, sleepiness and daytime behavior in preschool-age children. Journal of Child Psychology and Psychiatry, 50, 1532–1554. Goodnight, J. A., Bates, J. E., Staples, A. D., Pettit, G. S., & Dodge, K. A. (2007). Temperamental resistance to control increases the association between sleep problems and externalizing behavior development. Journal of Family Psychology, 21, 39–48. Iglowstein, I., Jenni, O. G., Molinari, L., & Largo, R. H. (2003). Sleep duration from infancy to adolescence: Reference values and generational trends. Pediatrics, 111, 302–307. Jenni, O. G., Molinari, L., Caflisch, J. A., & Largo, R. H. (2007). Sleep duration from 1 to 10 years: Variability and stability in comparison with growth. Pediatrics, 120, e769–e776. Jones, K., & Harrison, Y. (2001). Frontal lobe function, sleep loss and fragmented sleep. Sleep Medicine Reviews, 5, 463–475.



15

Jung, E., Molfese, V. J., Beswick, J., Jacobi-Vessels, J., & Molnar, A. (2009). Growth of cognitive skills in preschoolers: Impact of sleep habits and learning-related behaviors. Early Education and Development, 20, 713–731. Karpinski, A. C., Scullin, M. H., & Montgomery-Downs, H. E. (2008). Risk for sleep-disordered breathing and executive function in preschoolers. Sleep Medicine, 9, 418–424. Komada, Y., Abe, K. Y., Okajima, I., Asoka, S., Matsuura, N., Usul, A., : : : Inoue, Y. (2011). Short sleep duration and irregular bedtime are associated with increased behavioral problems among Japanese preschool-age children. Tohoku Journal of Experimental Medicine, 224, 127–136. Lam, J. C., Mahone, E. M., Mason, T. B. A., & Scharf, S. M. (2011). The effects of napping on cognitive function in preschoolers. Journal of Developmental & Behavioral Pediatrics, 32, 90–97. Lemola, S., Raikkonen, K., Scheier, M. F., Matthews, K. A., Pesonen, A.-K., Heinonen, K., : : : Kantajie, E. (2011). Sleep quantity, quality and optimism in children. Journal of Sleep Research, 20, 12–20. Ponitz, C. E. C., McClelland, M. M., Jewkes, A. M., Connor, C. M., Farris, C. L., & Morrison, F. J. (2008). Touch your toes! Developing a direct measure of behavioral regulation in early childhood. Early Childhood Research Quarterly, 23, 141–158. Randazzo, A. C., Muehlbach, M. J., Schweitzer, P. K., & Walsh, J. K. (1998). Cognitive function following acute sleep restriction in children ages 10–14. Sleep, 21, 861–868. Rothbart, M. K., Ahadi, S. A., Hershey, K. L., & Fisher, P. (2001). Investigations of temperament at 3–7 years: The Children’s Behavior Questionnaire. Child Development, 72, 1394–1408. Shin, N., Vaughn, B. E., Akers, V., Kim, M., Stevens, S. Krzysik, L. : : : Korth, B. (2011a). Are happy children socially successful? Testing a central premise of positive psychology in a sample of preschool children. Journal of Positive Psychology, 6, 355–367. Shin, N., Vaughn, B. E., Akers, V., Kim, M., Stevens, S. Krzysik, L., : : : Korth, B. (2011b). Are happy children socially successful? Testing a central premise of positive psychology in a sample of preschool children. Journal of Positive Psychology, 6, 366–367. Steenari, M. R., Vuontela, V., Paavonen, E. J., Carlson, S., Fjallberg, M., & Aronen, E. (2003). Working memory and sleep in 6- to 13-year-old schoolchildren. Journal of the American Academy of Child and Adolescent Psychiatry, 42, 85–92. Teti, D. M., Mayer, G. E., Kim, B.-R., & Countermine, M. (2010). Maternal emotional availability at bedtime predicts infant sleep quality. Journal of Family Psychology, 24, 307–315. Touchette, E., Petit, D., Séguin, J. R., Boivin, M., Tremblay, R. E., & Montplaisir, J. Y. (2007). Associations between sleep duration patterns and behavioral/cognitive functioning at school entry. Sleep, 30, 1213–1219. Vaughn, B. E., El-Sheikh, M., Shin, N., Elmore-Staton, L., Krzysik, L., & Monteiro, L. (2011). Attachment representations and sleep quality in preschool age children. Attachment & Human Development, 13, 525–540. Vaughn, B. E., Shin, N., Kim, M., Coppola, G., Krzysik, L., Santos, A. J., : : : Korth, B. (2009). Hierarchical models of social competence in preschool children: A multi-site, multi-national study. Child Development, 80, 1775–1796. Waiter, A. H., Mitschke, A. R., Widdern, S. V., Fricke, L., Breuer, U., & Lehmkuhl, G. (2005). Sleep disorders and behavioural problems among 8- to 11-year-old children. Somnologie, 9, 210–214. Walker, M. P. (2009). The role of sleep in cognition and emotion. Annals of the New York Academy of Sciences, 1156, 168–197. Walker, M. P., & Stickgold, R. (2006). Sleep, memory, and plasticity. Annual Review of Psychology, 57, 139–166. Ward, T. M., Gay, C., Anders, T. F., Alkon, A., & Lee, K. A. (2008). Sleep and napping patterns in 3-to-5-year old children attending full-day childcare centers. Journal of Pediatric Psychology, 33, 666–672. Waters, E., & Sroufe, L. A. (1983). Social Competence as a developmental construct. Developmental Review, 3, 79–97.

Parenting Practices and Perceived Social Support: Longitudinal Relations with the Social Competence of Mexican-origin Children.

Social support, family functioning and parenting competence in adolescent parents.

Social support and cognitive functioning as resources for elderly persons with chronic arthritis pain.

Social Competence with an Unfamiliar Peer in Children and Adolescents with High Functioning Autism: Measurement and Individual Differences.

Cognitive function in preschool children with sleep-disordered breathing.

Social knowledge and social competence: number and quality of strategies as predictors of peer behavior.

Peer status and classroom seating arrangements: a social relations analysis.

Sluggish cognitive tempo and peer functioning in school-aged children: a six-month longitudinal study.

Parenting and Preschool Self-Regulation as Predictors of Social Emotional Competence in 1st Grade.

Neurocognitive, Social-Behavioral, and Adaptive Functioning in Preschool Children with Mild to Moderate Kidney Disease.

Placebo sleep affects cognitive functioning.

Language in young children with neurofibromatosis-1: relations to functional communication, attention, and social functioning.

Relations between emotional and social functioning in children with anxiety disorders.

Executive function is associated with social competence in preschool-aged children born preterm or full term.

Social relations, social support and survival among patients with cancer.

Cognitive structures, language, and emerging social competence in autistic and aphasic children.

Long-Term Cognitive and Behavioral Outcomes following Resolution of Sleep Disordered Breathing in Preschool Children.

Field independence and intellectual functioning in preschool children.

Bullying in preschool: The associations between participant roles, social competence, and social preference.

An epidemiologic study of deciduous molar relations in preschool children.

Self-efficacy as a predictor of self-reported physical, cognitive, and social functioning in multiple sclerosis.

Relations among motor, social, and cognitive skills in pre-kindergarten children with developmental disabilities.

Peer status and the directionality of symptomatic behavior: prime social competence predictors of outcome for vulnerable children.

Social competence among well-functioning adolescents with epilepsy.