Abstract
Nature-based education has grown exponentially throughout the United States. However, it has yet to be determined to what extent these programs are preparing children for formal schooling in kindergarten and beyond. This study directly assessed school readiness (i.e., early literacy and executive function) skills of children who attended a nature-based preschool (n = 82; M age = 47.75 months) in comparison to children in a non-nature preschool setting (n = 58; M age = 50.16 months) in the fall and spring of one school year. Nature-based classrooms were shown to spend, on average, two hours more outside than the non-nature classrooms. Children at both locations developed skills in early literacy and some aspects of executive function (e.g., working memory and inhibitory control) at similar rates. Other aspects of executive function, such as behavioral self-regulation, were associated with greater growth for children attending non-nature classrooms. This study suggests high-quality nature-based preschools can be successful at promoting many areas of children’s school readiness but may need to be more intentional when supporting the development of some aspects of executive function.
Keywords
Nature-based education is a growing educational practice throughout the United States due to the numerous socioemotional and physical benefits for children from learning outdoors (Bartlett, 1996; Fjørtoft, 2001; McCurdy et al., 2010). From 2008 to 2017, the number of nature-based early childhood programs in the U.S. has increased from 20 to over 250 (Merrick, 2016; North American Association for Environmental Education (NAAEE), 2017), with this number doubling to over 585 nature-based early childhood programs in 2020 (NAAEE, 2020). In addition, recent global health issues have led parents, teachers, and administrators to search for safe and in-person options to schooling (Inside-Outside, 2020), particularly for young children. Proponents of nature-based education argue that the outdoors can be used as an effective classroom setting, but that nature should also be integrated into the daily curriculum to promote learning (Sobel, 2016). This study investigates whether a nature-based approach to learning supports the development of the academic and socioemotional skills children need to be prepared for kindergarten.
Nature-based education includes a number of curricular approaches, including programs that go by the following names: nature-based preschools, forest kindergartens, and forest schools. Although programs vary in the amount of time spent outside (Larimore, 2016), they all incorporate opportunities for children to have frequent experiences with nature, which is thought to support their development and build a lasting connection to nature. The current study focuses specifically on nature-based preschools. As of 2023, nature-based preschools could be found in more than 45 states in the United States. Despite the substantial increase in nature-based programs, most information about the educational practices employed in these settings is based on anecdotes. It is currently unclear whether this approach can lead to the academic and socioemotional gains, such as executive function, that young children need to be prepared for kindergarten.
Nature-Based Classrooms
While there are many different models of teaching within nature-based early childhood education, all involving different amounts of time spent outdoors, curriculum used, length of the program, the ages served, and role of parents and families (NAAEE, 2017), the current study focuses on nature-based preschools specifically. Nature-based preschools are typically licensed early childhood programs for 3–5 year olds, where nature is core in the curriculum and children spend at least 30% of their class day outdoors unless the weather is dangerous (Bailie, 2010; Larimore, 2019). For example, rainy weather could keep a non-nature classroom indoors for an afternoon, but a nature-based classroom might see this event as an opportunity for children to collect and learn about worms who have come above ground (e.g., Jacobi-Vessels, 2013). Further, in a nature-based preschool nature is incorporated into and connects across all learning spaces (Finch & Bailie, 2015; Larimore, 2019). These spaces can include an indoor space, natural outdoor play area, and areas beyond the boundary of the play area (Larimore, 2019; Warden, 2012, 2015). Nature-based preschools typically use an emergent curriculum where activities emerge from children’s experiences and interests in the natural world (Finch & Bailie, 2015; Larimore, 2019; Warden, 2012). As a result, all three spaces are used as an intentional setting for academic learning (e.g., literacy, math, science), in addition to motor and social development (Finch & Bailie, 2015; Larimore, 2011; Natural Start Alliance, 2017).
Nature-based preschools are becoming more common in the United States (NAAEE, 2020) and much has been written about how to embed nature within classrooms and curriculum (Natural Start Alliance, 2017). Yet, it is still unclear how teaching practices in nature-based preschools compare to more non-nature approaches and how nature-based pedagogy impacts children’s development. In fact, nature-based learning scholars have called for additional research related to learning outcomes, mechanisms of influence, and implications for policy and practice (Jordan & Chawla, 2019). Specifically, they posed the question, “How do nature-based preschools and kindergartens compare with conventional early childhood programs that emphasize indoor learning in terms of preparing children for school readiness?” (Jordan & Chawla, 2019, p. 5). The current study is among the first to begin to answer this question by providing data on how educators support preschoolers’ school readiness within a nature-based educational framework.
Differences in Nature-based and Non-nature Classrooms
Although high-quality nature-based and non-nature programs have similar developmental goals for children, we hypothesize the fundamental differences in pedagogy may influence child outcomes. In particular, time spent outdoors, utilization of outdoor space, and use of emergent curriculum are philosophically different across the two program types.
Time Spent Outdoors
One of the fundamental differences between nature-based and non-nature programs is the amount of time each program spends outdoors. Nature-based preschools typically spend between 30–100% of their classroom time outdoors (Bailie, 2010; Larimore, 2019). While the amount of time indoors varies by program, most programs are only indoors if the weather is dangerous. At a non-nature preschool, children typically spend less than 60 minutes outside daily (Byrd-Williams et al., 2019; Reilly, 2010), with the length of outdoor time being heavily influenced by the minimum necessary for licensing.
Outdoor Space
Another difference between nature-based and non-nature programs is how each program utilizes their outdoor space. Nature-based programs typically have two distinct outdoor spaces for children to learn in: a managed outdoor space and an area “beyond” the fence (Larimore, 2019; Warden, 2012, 2015). A managed outdoor space is a regularly used outdoor environment designed to facilitate children’s learning and play (NAAEE, 2019). These are also referred to as play space, outdoor classroom, or outdoor learning environment. These spaces offer similar experiences to those of a more traditional playground, with opportunities for children to climb, swing, dig, and balance; however, these activities are done with natural features that can change and grow (NAAEE, 2019). For example, instead of playing on a play structure, children at a nature-based program may be observed climbing a tree or walking on fallen logs. In addition to the managed outdoor space, nature-based programs often incorporate experiences “beyond” the fence in “wild” spaces (NAAEE, 2019). Experiences in these spaces allow children to access a range of local ecosystems and explore the differences between these ecosystems. In contrast, non-nature programs primarily utilize an outdoor play space with traditional play elements (e.g., swing set, play structure, etc.). When non-nature programs do go outside, this time is primarily used as an opportunity for a break, with many teachers missing opportunities to enhance children’s learning and capitalize on children’s interest in the outdoors (Maynard & Waters, 2007).
Emergent Curriculum
The National Institute for Early Education Research has provided some guidance on how a high-quality preschool should support children’s emerging interests (Espinosa, 2002). Both preschool types typically endorse a philosophy that promotes child-directed learning with a set daily schedule (Frost et al., 2012; Samuelsson & Johansson, 2006). While prior research shows non-nature preschools are more likely to focus on teacher-planned activities and specific subject content knowledge (Bennett & Tayler, 2006), nature-based preschools often base activities in seasonal events occurring in nature (Finch & Bailie, 2015). This allows teachers to approach teaching using an emergent curriculum, where lessons develop based on what is happening in the natural environment and the curiosity of the children (Finch & Bailie, 2015; Klaar & Öhman, 2014). For example, a nature-based classroom may have planned to spend the first week of spring learning about flowers; however, the lesson could be adapted to one about how plants survive winter temperatures if there is still snow on the ground. It is unclear how this more flexible approach to instruction impacts the classroom environment and overall learning goals of the program.
Interactions with Nature and Child Development
In addition to understanding the philosophical differences in each approach, the efficacy of nature-based preschool programs must be considered in light of state standards for kindergarten readiness, which emphasize language and early literacy development, social, emotional, and physical health development, and early math, science and social studies skills (California Department of Education, 2008; Michigan State Board of Education, 2005; New Jersey State Department of Education, 2014). There is evidence to suggest that spending time outdoors benefits children physically, academically, and social-emotionally, yet more work is needed to examine the benefits of nature as a school setting for preschool children.
Physical Benefits
Children who participate in more outdoor activities, particularly in nature, are less likely to have asthma, myopia, and chronic pain issues (McCurdy et al., 2010). Additionally, access to natural play areas have been shown to improve coordination, balance, and agility; prevent sickness (Fjørtoft, 2001); and help reduce stress in children (N. M. Wells & Evans, 2003). When looking at nature-based education facilities, researchers have suggested that playing in nature can provide children an opportunity to be more adventurous and take appropriate risks, which can build confidence and teach children to make personal judgments (Finch & Bailie, 2015). Building on existing knowledge about the benefits of nature for physical health (Fjørtoft, 2001; McCurdy et al., 2010), the current study investigates whether nature-based programming supports children’s development in other areas, specifically in academic and socioemotional skills.
Academic Benefits
In general, nature-based education has been found to support academic outcomes in children. In a systematic review looking at children 4 to 12 years old, nine out of eleven studies reported an improvement in educational outcomes, including reading, spelling, mathematics, writing, literacy, science, disposition to learn, and learning motivation for children who took part in nature-based learning (N. C. Miller et al., 2021). Of the two studies that did not show improvement, one did not report statistical significance and the other showed neutral effects on academic attainment. However, only two studies in this review included preschool aged participants, one with physical development as their primary outcome and the other with science achievement as their primary outcome. While these results are promising, the current study focuses specifically on language and literacy skills in preschoolers, as early accomplishments in these areas are predictive of academic success in elementary and middle school (Duncan et al., 2007; McClelland et al., 2006).
Although different from non-nature preschool classrooms, nature-based classrooms endeavor to foster early language and literacy development by allowing children to investigate the natural world around them. While these subjects are not explicitly studied in nature-based classrooms, allowing children to explore their natural world can provide opportunities for growth in receptive and expressive language, print knowledge, and writing skills (Conezio & French, 2002). Researchers have found that children gain and solidify literacy skills when they have the opportunity to use these skills in meaningful ways (Christie & Roskos, 2006; Duke et al., 2006). Proponents of nature-based education argue that interacting with nature can provide children with meaningful opportunities for conversation and literacy (Streelasky, 2019). For example, Harwood and Collier (2017) discuss the many ways a nearby forest helped to enhance communication and storytelling in one classroom, specifically through children’s play and literacy framing. In addition to early literacy skills, nature-based programs have been shown to frequently use science journals throughout their classrooms. These journals allow children to practice their emergent writing skills while also practicing sounding out the letters needed to spell science-specific words as they label their observations (Brenneman & Louro, 2008). Moving beyond preschool classrooms, nature-based elementary classrooms have been shown to increase the motivation to read, write, and draw, particularly in children who previously struggled with participating in literacy activities, because children wanted to learn more about what they were witnessing in nature (Eick, 2011).
Socioemotional Benefits
In addition to academic benefits, it is important to examine to what extent nature-based education is related to socioemotional development, given recent policy reports stressing its importance in helping children to succeed within an educational setting (Zelazo et al., 2016). In regard to children’s interpersonal and social skills, natural environments have been shown to help stimulate interactions between older children (Bixler et al., 2002), while also helping them develop independence and autonomy (Bartlett, 1996). Teachers have reported noticeable decreases in children’s antisocial behaviors, such as violence and bullying, when schools incorporate more diverse natural environments for children to play in (Malone & Tranter, 2003). Additionally, teachers report that children exhibit increases in behavioral self-regulation, creativity, and self-confidence after being in nature; they also noted that children had increased socialization skills, problem-solving skills, and ability to focus (Brussoni et al., 2017), which are critical skills children need to be successful in school. While a majority of prior research has mainly focused on children’s play in natural environments, work is just beginning to look at how nature-based educational settings impact children’s development. When looking at nature-based preschools specifically, one study has shown that these types of programs help to increase peer play skills in children when compared to children who attend a non-nature preschool (Burgess & Ernst, 2020). Some have also suggested that nature-based educational settings can enhance children’s critical thinking and leadership skills and allow children to develop social and emotional skills through play in nature (Finch & Bailie, 2015). These results are promising; however, more work needs to be done to see if these findings replicate beyond this initial study.
Executive function skills are an area that has been found important for academic readiness in preschool and beyond (McClelland et al., 2007; Schunk & Ertmer, 2000). Executive function includes the mental processes that enable a person to plan, focus attention, remember instructions, and juggle multiple tasks successfully (Garon et al., 2008). Models of executive functions often incorporate skills related to inhibitory control (i.e., one’s ability to control impulses), cognitive flexibility (i.e., one’s ability to switch attention), and working memory (i.e., one’s ability to hold onto and use information; Ackerman & Friedman-Krauss, 2017). Each of these skills individually has been shown to be related to children’s academic performance (Olson et al., 2005; Skibbe et al., 2019; Zelazo et al., 2003). Although inhibitory control, cognitive flexibility, and working memory have their own unique function and contribution to learning, research argues that the integration of these three components also helps to guide goal-directed behavior, specifically in young children (Best et al., 2009; Diamond, 2013; Garon et al., 2008; McClelland et al., 2007, 2014). This integration of all three EF processes is required for children to navigate the demands of school successfully (McClelland & Cameron, 2012).
There are many theoretical frameworks that provide context on the ways in which EF development may differ in nature-based and non-nature preschool classrooms. First, Attention Restoration Theory (ART) posits that time in natural environments helps restore one’s ability to concentrate (Kaplan & Kaplan, 1989). This suggests that children who attend nature-based preschools would have greater EF than children at non-nature programs due to spending more time in nature. However, there has yet to be support for this theory in young children, and empirical evidence with adults has shown mixed findings (Ohly et al., 2016). Second, the EF model proposed by Diamond (2013) suggests that EF skills can develop differently based on different environmental contexts (Munakata & Michaelson, 2021). It is possible that children will develop certain EF skills differently depending on whether they attend a nature-based preschool or a non-nature one. For example, nature-based classrooms may better support cognitive flexibility in children due to their focus on emergent curriculum, whereas the program structure of a non-nature classroom may better support children’s behavioral self-regulation due to the more consistent schedule. Finally, in addition to different environmental contexts to support EF skills, these skills may develop differently in each setting due to how the environments support different interactions between children and educators. Vygotsky’s sociocultural theory states that children’s higher mental functions (e.g., EF) are developed from children’s interactions and thus are taught, either formally or informally, within social contexts (Vygotsky, 1978). It is possible that the more structured activities within non-nature preschool programs lend themselves better to social interactions that support the development of certain EF skills, while the interactions more likely to occur at nature-based preschool programs support the development of other EF skills. While there is theoretical support for the nature-based preschools supporting children’s EF development, empirical evidence is lacking, and we need to examine these differing perspectives within a nature-based preschool setting.
While not examined in a nature-based preschool setting specifically, time in nature has been shown to provide a unique setting for the development of EF skills. Children who have more contact with nature are shown to have increased attention spans, creative thought processes, problem solving abilities, self-discipline, and behavioral self-regulation (Burdette & Whitaker, 2005). Children with ADHD were able to concentrate better after a walk in the park than after a walk through downtown or a neighborhood (Faber-Taylor & Kuo, 2009). For children ages 5 and 6, researchers found positive relations between the amount of time a child spends outside daily and their attention skills (Ulset et al., 2017). In addition, preschoolers who had taken a walk in nature performed better on attention tasks and spatial working memory tasks than children who went on a walk in an urban area (Schutte et al., 2017). However, further research needs to be done to determine if and how executive function skills develop in a nature-based preschool in comparison to non-nature preschools.
The Current Study
Our overarching aim is to investigate how preschoolers are being prepared for kindergarten in a nature-based program compared to a non-nature preschool. With this purpose in mind, our work was guided by two research aims.
1) Investigate the amount of time each type of preschool spends outdoors during a typical day.
2) Determine if children who attend a nature-based preschool develop early literacy and executive function skills at a similar rate as children who attend a non-nature preschool.
Method
Participants
Classroom Observation
This study included two preschools in suburban areas in the Upper Midwest that were both considered high-quality per the state’s quality rating improvement scale. The state’s quality rating assessment looked at five areas of each program when determining the level of quality. The five areas examined to determine quality were the learning environment, daily routine, adult-child interactions, curriculum planning and assessment, and the safety and health of the environment. These quality indicators were aligned with the state’s early childhood standards of quality, along with national indicators from the National Association for the Education of Young Children (NAEYC), the National Association for Family Child Care (NAFCC), and the Classroom Assessment Scoring System (CLASS; Pianta et al., 2008). One school self-identified as nature-based. The non-nature preschool was also accredited by NAEYC and operated as a laboratory school for the preparation of future teachers. The director of the nature-based preschool reached out to our research team for formal evaluation, after they had previously collected anecdotal evidence from families and teachers about the benefits of the nature-based approach. The non-nature school was then selected after researchers searched for a program similar in quality as well as demographics. The constructs investigated as part of this study (i.e., early literacy and executive function) were up to the discretion of the research team and chosen to reflect important, but separate, skills needed for kindergarten readiness. Both schools served children ages 3 to 5 years old. In addition to the self-described nature-based approach, the nature-based preschool used Creative Curriculum (Dodge, 1988) as its curriculum and Teaching Strategies Gold (Lambert et al., 2015) for child-level assessment. The non-nature preschool varied in curriculum by classroom with one using the Reggio-Emilia approach, one the Project Approach, and one High/Scope (Schweinhart & Hohmann, 1992).
Combined there were six classrooms in this study serving preschool-aged children (n = 3 nature-based classrooms; 3 non-nature classrooms). Five of the six classrooms were half-day programs (i.e., 3 hours) and one in the non-nature setting was a full-day program (i.e., 6 hours). Sessions within each classroom ranged in length from 2–4 days per week. Both programs had at least three adults in the classroom with a maximum of 20 children ranging in age from three to five years old.
Direct Assessments
Nature-based Preschool
Eighty-two children were recruited from the morning and afternoon sessions at the nature-based preschool (N = 27 female, 55 male). Children ranged in age from 3 to 5 years old (M = 47.75 months, SD = 7.04). Mothers were asked to report their highest level of education; 1.2% completed high school (n = 1), 17.1% attended some college (n = 14), 46.3% attained an undergraduate degree (n = 38), and 32.9% completed graduate/professional school (n = 27). In this sample, most of the children (90.2%) were identified as white (n = 74); in addition, 2.4% of children were American Indian/Alaskan (n = 2), 3.7% were Asian/Pacific Islander (n = 3), and 3.7% reported that their child was best represented by another ethnicity not listed (n = 3). This is reflective of nature-based preschools in general, with a national survey on enrollment in nature-based programs indicating approximately 83% of the children enrolled were white, 1% American Indian/Alaska Native, 6% Asian, and 1% as other.
Non-nature Preschool
Fifty-eight children participated from the non-nature preschool (N = 29 female, 29 male). Children ranged in age from 3 to 5 years old (M = 50.16 months, SD = 6.51). Mothers were asked to report their highest level of education; 6.9% attended some high school (n = 4), 1.7% had a high school degree (n = 1), 10.3% completed some college (n = 6), 31% attained an undergraduate degree (n = 18), and 48.3% completed graduate/professional school (n = 28). In this sample, 67.2% children were identified as white/Caucasian (n = 39), 12.1% as Asian/Pacific Islander (n = 7), 3.4% as Black/African American (n = 2), 3.4% as American Indian/Alaskan (n = 2), as 1.7% Hispanic/Latino (n = 1), and 12.1% as “other” (n = 7).
There were no significant differences in maternal education (t(90.09) = −.14, p = .89), or household income (t(90.88) = .22 p = .83) between the two preschools. However the nature-based preschool had significantly more white/Caucasian children (t(88.64) = 3.27, p = .002) and more boys than the non-nature program did (t(117.85) = 2.02, p < .05). In addition, the nature-based preschool was shown to have more native speakers in attendance (t(70.48) = 2.80, p = .007), when reported by parents. Finally, children who attended the non-nature preschool were shown to be older by approximately two months (t(125) = −2.08, p = .03) and more had an individualized education plan (IEP; t(70.80) = −2.79, p < .007). As a result of the differences in demographic characteristics, demographic characteristics that differed significantly by preschool location were used as covariates in further analysis. See Table 1 for the full demographic characteristics of each preschool.
Demographic Information of Study Participants by Preschool Type
Note: *p<.05; **p<.01
Measures
Each classroom was observed to investigate the average amount of time children at each type of program spent outdoors. Observations were scheduled at the teachers’ convenience and on days when they were following their typical classroom schedule. For all six classrooms, data collection lasted three hours, which for five of six classrooms was the entirety of the class session. Observers noted the time each classroom went outdoors and returned to the indoor classroom.
Direct assessments were used to measure child outcomes in the fall and spring of one school year. After parents consented to have their child participate in this study and filled out a demographic questionnaire, trained research assistants then obtained verbal assent from the child and then took the child to a quiet space to conduct the assessment battery. For children at the non-nature preschool, testing usually took place in a hall or a quiet side room. For children at the nature-based preschool, testing occurred in the indoor classroom space while lessons were continuing outside. Testing sessions lasted approximately 30 minutes and assessments were given in random order.
Early Literacy
Phonological Awareness
The phonological awareness subtest of the Test of Preschool Early Literacy Skills (TOPEL; Lonigan et al., 2007) was used to measure children’s understanding of the sound structure of language using elision and blending tasks. Elision tasks required children to drop part of a word to create a new word (e.g., “Point to shoot without /t/”). The blending task required children to combine words or sounds to make new words (e.g., “What word do these make? Hot—Dog.”). The pause between words was approximately one second. Total correct items were added up and are transformed into a standard score, based on age (M = 98.26, SD = 15.90). The internal consistency was above .90 for 3 to 5 year olds.
Letter Name Knowledge
The Quick Letter Name Knowledge (Q-LNK) assessment (Tortorelli et al., 2017) was used to measure participants’ knowledge of letter names. This measure was developed using Item Response Theory as a way to accurately assess children’s letter name knowledge from eight items (Bowles et al., 2014). Children were assessed using one of the six possible forms and asked to identify lower- and upper-case letters presented to them. In order to ensure accurate comparisons between children’s letter name knowledge, children’s assessment score (range 0–8) was translated to their Expected Total Letters Known (Range 0–52). Reliability for the different forms ranged from .89 to .92.
Letter Sound Knowledge
The Letter Sound Knowledge (LSK) assessment (Piasta et al., 2016) was used to measure participants’ knowledge of the sound’s letters produce. Similar to the Q-LNK, Item Response Theory was used to accurately assess children’s knowledge of letter sounds from six items. Children were assessed using one of four possible forms and asked to pronounce the sounds associated with letters (Range 0–6). In order to ensure accurate comparisons between children’s letter sound knowledge, their raw score was converted to a scale to measure a child’s expected letter sound knowledge (Range 0–26). All forms of this measure have shown reliability between .89 and .93.
Executive Function
Inhibitory Control
The National Institutes of Health -Toolbox (NIH-TB) Flanker Inhibitory Control and Attention Test (Weintraub et al., 2013) was used to measure children’s ability to inhibit visual attention to irrelevant task dimensions. On each trial, a central target (fish are used for children younger than 8 years old) is flanked by similar stimuli on both sides. The task is for the child to identify the direction of the central fish. Raw scores were used in analysis; possible scores ranged from 0 to 40. Reliability was measured at 0.96.
Working Memory
The NIH-TB Picture Sequence Memory Test (Weintraub et al., 2013) was used to measure episodic memory in participants. For each trial, pictures are shown, then moved to a fixed location one at a time until the entire sequence is displayed. The pictures are returned to the center and the participants must move them back into the sequence previously demonstrated. Raw scores were used in analysis and possible scores ranged from 0 to 13. Reliability has been measured at 0.78.
Behavioral Self-Regulation
Head-Toes-Knees-Shoulders (HTKS; McClelland et al., 2014) was used to measure children’s behavioral self-regulation. Children were asked to respond with the opposite action of verbal requests (i.e., when told “touch your head,” children touch their toes). After the first section, two more commands and corresponding actions are added (knees/shoulders, shoulders/knees), before the third section changes the actions that correspond to each command (i.e., when told “touch your head,” the child touches their knees, and when told to “touch your knees,” the child touches their head. Same with shoulders and toes). There were three sections total, each with 10 actions for the child to perform for a total of 30 possible items, however, a child can only move to the next section by scoring 4 or more points on the previous section. Correct responses earn the child 2 points; incorrect responses earn 0 points; and 1 point is earned when the child self-corrects his/her actions. Possible scores range from 0 to 60, with higher scores indicating a higher level of behavioral self-regulation. HTKS has shown interrater reliability of .90 and demonstrated predictive validity for academic achievement outcomes (Schmitt et al., 2014; Skibbe et al., 2019).
Results
Time Outside
All preschool classrooms in this study engaged in free play, morning meeting, large group, small group, and choice time. See Table 2 for a detailed breakdown of the amount of time each classroom spent in each activity and the location of each activity (i.e., indoor classroom, outdoor play area, and area beyond the fence). On average, children at the nature-based preschool spent approximately 147 minutes (SD = 43.35) outside, whereas the non-nature preschool spent an average of 36 minutes outside (SD = 9.29). A t-test was used to assess the difference in time spent outdoor at each preschool location, this difference was found to be statistically different between the two sites (t(2.19) = −4.30, p < .05). In addition, the nature-based classrooms were observed leaving the outdoor play area and venturing into the area beyond the fence (i.e., the “beyond” or “wild” spaces). This began as taking a short hike through the woods to get to the next activity. Two nature-based classrooms utilized learning spaces in the woods that had logs/tree stumps set up for children to sit on for their next activity. The third nature-based classroom continued walking, as their activity was to collect various objects they found in the woods. The amount of time each nature-based classroom spent beyond the outdoor play area ranged from 27.06 to 43.30 minutes. Classrooms at the non-nature program did not leave the outdoor play area.
Components of the School Day
Note. The order of activities varied by classroom. Morning Meeting at the non-nature classrooms included planning time. Second Free Play time at non-nature classrooms included transition time to move from indoor classroom to outside.
Children’s Growth in Early Literacy and Executive Function Skills
To determine the rate at which early literacy and executive function skills developed for children at both preschool settings, multiple one-way between-groups analyses of covariance were conducted to measure the growth in children’s skills over the school year. There was a higher rate of refusal when conducting some of the spring assessments from children who attended the nature-based preschool; therefore, growth scores were only calculated for children who had data at both timepoints. Due to differences in the demographic make-up of each preschool location, demographic characteristics that differed significantly across locations were used as covariates in further analysis. Children’s gender, age, if they identified as white, if they were a native speaker, and IEP status were used as the covariates in this analysis. In addition, we further examined the results presented below by conducting the analysis separated by gender at each preschool location. When we conducted the analysis separated by gender, we found the results were equivalent to the findings utilizing the full sample. Thus, we retained the full sample and only present the findings for the full sample below. Means and standard deviations for each assessment at both fall and spring timepoints, separated by group, are presented in Table 3. Children at both preschool locations were shown to have statistically equivalent baseline scores on all assessments (see Table 4).
Descriptive Statistics for Outcome Variables by Preschool Type
Independent Sample T-Test for Baseline Equivalency on Study Variables
Note. M = Mean. SD = Standard Deviation. Fall scores were used to assess baseline equivalency between preschool setting.
Early Literacy
Children who attended the nature-based preschool showed equivalent growth to children who attended a non-nature preschool on all three early literacy skills.
Phonological awareness
There were no significant differences in fall phonological awareness scores for children who attended the nature-based preschool (M = 100.23, SD = 15.08) and children who attended the non-nature preschool (M = 94.60, SD = 16.70); t (111) = 1.85, p = .07). The magnitude of the differences in the means (mean difference = 5.62, 95% CI: −.41 to 11.66) was small (eta squared = .03). Children’s spring phonological awareness scores (nature-based: M = 103.03, SD = 13.82; non-nature: M = 97.60, SD = 17.45) were used to calculate the growth each child made over the school year. After adjusting for participants’ demographic differences (i.e., gender, age, white, native English speaker, and presence of an IEP) there was no significant difference between the two preschools on phonological awareness growth, F (1, 90) = 1.41, p = .24. The mean difference in children’s phonological awareness growth scores, after using a Bonferroni adjustment was 1.33, 95% CI [−.90, 3.55], with a partial eta squared = .015 showing a small effect of classroom type on children’s phonological awareness. This shows children at both preschools gained equivalent phonological awareness skills over the course of the school year.
Letter name knowledge
On average, children who attended the non-nature preschool knew about 5 letters more at the start of the year (M = 23.26, SD = 17.67) than the children who attended the nature-based preschool (M = 18.36, SD = 17.30); however, this difference was not statistically significant (t (122) = −1.52, p = .13). The magnitude of the differences in the means (mean difference = −4.90, 95% CI: −11.27 to 1.45) was small (eta squared = .03). Children’s letter name knowledge growth was calculated from their spring scores (nature-based: M = 24.74, SD = 16.87; non-nature: M = 31.77, SD = 16.84). After controlling for children’s demographic differences, no significant difference was found between children who attend the nature-based and the non-nature preschool, F (1, 92) = .34, p = .56. The mean difference in children’s letter name knowledge growth scores, after using a Bonferroni adjustment was −1.78, 95% CI [−7.79, 4.22]. The partial eta squared = .004, showing a small effect size and demonstrating that children learned a similar number of letters across preschool settings.
Letter sound knowledge
There were no significant differences in letter sound knowledge between children who attended the nature-based preschool (M = 5.23, SD = 6.56) and children who attended the non-nature preschool (M = 6.96, SD = 7.10; t (120) = −1.38, p = .17, two-tailed). The magnitude of the differences in the means (mean differences = −1.73, 95% CI: −4.22 to .76) was small (eta squared = .02). Children at both preschools showed growth in their spring letter sound knowledge (nature-based: M = 7.50, SD = 7.33; non-nature: M = 9.87, SD = 8.76). There was no significant difference in growth in letter sound knowledge between children who attended the nature-based preschool and children who attended the non-nature preschool after controlling for demographic differences, F (1, 91) = .001, p = .97. The mean difference in children’s letter sounds knowledge growth scores, after using a Bonferroni adjustment was −.06, 95% CI [−3.12, 3.01] with an effect size calculated using partial eta squared equaled .000, showing equivalent growth for children at both preschools in their letter sound knowledge with no effect for preschool program type.
Executive Function
Children who attended a nature-based preschool were shown to make equivalent gains on working memory and inhibitory control. However, children who attended the non-nature preschool were shown to make more gains in behavioral self-regulation.
Working memory
There were no significant differences in working memory scores for children who attended the nature-based preschool (M = 2.99, SD = 3.09) and children who attended the non-nature preschool (M = 3.38, SD = 3.13; t (118) = −.70, p = .49, two-tailed). The magnitude of the differences in the means (mean difference = −.40, 95% CI: −1.53 to .73) was very small (eta squared = .004). Children’s growth in working memory was calculated from children’s spring scores (nature-based: M = 4.44, SD = 3.57; non-nature: M = 3.32, SD = 3.90). After controlling for differences in children’s demographic make-up, there was no significant difference between the two schools on working memory growth, F (1, 89) = .023, p = .88. The mean difference in children’s working memory growth scores, after using a Bonferroni adjustment was .12, 95% CI [−1.46, 1.70], partial eta squared = .000, demonstrating that children at both preschools gained equivalent working memory skills over the course of the school year with no effect based on type of preschool program.
Inhibitory control
There were no significant differences in initial scores of inhibitory control skills for children who attended the nature-based preschool (M = 19.98, SD = 10.51) and children who attended the non-nature preschool (M = 19.17, SD = 11.07; t (109) = .39, p = .69, two-tailed). The magnitude of the differences in the means (mean difference = .74, 95% CI: −3.28 to 4.91) was very small (eta squared = .001). Children’s growth in inhibitory control was calculated from children’s spring scores (nature-based: M = 23.38, SD = 11.96; non-nature: M = 26.69, SD = 11.99). Children at both preschools were shown to develop inhibitory control skills in equivalent ways, F (1, 81) = 3.66, p = .06, after controlling for demographic differences. The mean difference in children’s inhibitory control growth scores, after using a Bonferroni adjustment was −5.16, 95% CI [−10.52, .21] with a small effect (partial eta squared = .04) showing no significant difference in inhibitory control skills for children based on preschool type.
Behavioral self-regulation
There were no significant differences in initial scores of behavioral self-regulation for children who attended the nature-based preschool (M = 14.26, SD = 17.62) and children who attended the non-nature preschool (M = 13.47, SD = 16.34; t (111) = .24, p = .81, two-tailed). The magnitude of the differences in the means (mean difference = .79, 95% CI: −5.79 to 7.37) was very small (eta squared = .001). Children’s growth in behavioral self-regulation was calculated from their spring scores (nature-based: M = 13.25, SD = 16.87; non-nature: M = 22.70, SD = 18.59). Children at the non-nature preschool were shown to demonstrate more behavioral self-regulation, F (1, 87) = 16.59, p < .001. The mean difference in children’s behavioral self-regulation growth scores, after using a Bonferroni adjustment was −15.73, 95% CI [−23.40, −8.05]. The effect size was small, with a partial eta squared of .16, showing children who attended a non-nature preschool grew more in their behavioral self-regulation skills.
Discussion
As nature-based programs become more popular within the United States (NAAEE, 2020), it is important to consider to what extent these settings support children’s development during preschool. This study was one of the first to address the research agenda on nature-based learning set forth by the NBLR Network (Jordan & Chawla, 2019). In particular, our goal was to begin to answer the question “How do nature-based preschools compare with conventional early childhood programs that emphasize indoor learning in terms of preparing children for school readiness?” (Jordan & Chawla, 2019, p. 5). Spending more time outdoors has been shown to have numerous health benefits for children (McCurdy et al., 2010) and our results suggest that it can promote development in many areas in ways that are similar to that of a non-nature classroom. Children in both types of programs showed similar rates of development in early literacy skills, working memory, and inhibitory control over the course of one school year. Likely, this reflects the kind of the instruction provided within these settings. However, children in the non-nature preschool setting developed more behavioral self-regulation skills over the course of the year when compared to peers attending a nature-based program, warranting exploration of what nature-based programs can do to better support the development of this skill in young children. Findings are discussed at greater length below.
Nature-Based Preschool Classrooms
Nature-based programs were shown to emphasize child-directed learning throughout their daily schedule (Frost et al., 2012; Samuelsson & Johansson, 2006), using a mix of teacher-planned activities (Bennett & Tayler, 2006) and free play opportunities. Although nature-based classrooms were observed to resemble non-nature classrooms in several ways, there was one clear difference; nature-based classrooms worked on many of their curricular goals outdoors. In fact, children who attended the nature-based preschool spent on average 2 hours longer outdoors than children at the non-nature preschool. Consistent with past recommendations for nature-based programs (Kenny, 2013; Larimore, 2011; Sobel, 2014), the nature-based classrooms in this study spent between 1.5 and 3 hours outdoors. While outdoors, children engaged in activities present in a non-nature classroom such as free play and small group and large group activities. In addition, children at the nature-based preschool were allowed to have unstructured time in more remote and naturalized areas (Finch & Bailie, 2015). In contrast, the non-nature classrooms went outdoors for less than the recommended 60 minutes, which is typical of most non-nature classrooms (Byrd-Williams et al., 2019; Reilly, 2010). When the non-nature classrooms were outdoors, few learning opportunities related to early literacy or executive were observed. For example, children were encouraged to run off excess energy and play, while teachers were mainly observed supervising children’s safety and mediating conflicts. This practice is typical in non-nature preschools (Brown et al., 2009; McClintic & Petty, 2015) however, may suggest that non-nature programs are missing opportunities for children to learn in the outdoor environment (White, 2011).
Early Literacy
The nature-based and non-nature preschools provided similar activities for children to learn early literacy skills. Specifically, there was a focus in all classrooms on phonics, letter identification, and early decoding skills. All teachers sang songs throughout their day, which has been shown to support language and literacy skills in children (Hansen et al., 2014; Mizener, 2008; Wiggins, 2007). Many classrooms, at both locations, asked children to generate rhymes during activities, which can help to develop phonological awareness skills (Gillon, 2017). For the development of decoding skills, both preschools focused on children’s understanding of letter names and the sounds associated with them (Kendeou et al., 2009; Roberts et al., 2019). All three of these activities help preschool children gain skills necessary to be ready for future schooling (Downer & Pianta, 2006; Duncan et al., 2007). Findings suggest that high-quality early literacy instruction can be provided in a variety of settings. In addition, early literacy learning activities taking place outdoors setting can be as efficacious as instruction provided indoors.
Executive Function
The findings in this study related to executive function were mixed, as children displayed equivalent growth in working memory and inhibitory control, yet children who attended the non-nature preschool showed more growth in behavioral self-regulation compared to children who attended the nature-based preschool. These results are surprising, as previous work has suggested that more time in nature is beneficial to the development of behavioral self-regulation skills (Burdette & Whitaker, 2005).
Similar growth in working memory and inhibitory control between children who attended either type of preschool program expands the existing literature on the role nature plays in the development of children’s working memory and inhibitory control. Both the nature-based preschool and the non-nature preschool included activities that required mnemonic skills (e.g., children “recalled” where they had played throughout the day). These types of activities have been shown to promote working memory in young children (Bodrova & Leong, 2007). Both types of preschools also included prompts which encouraged children to practice inhibitory control skills. For example, teachers at the nature-based preschool were observed playing “Red light, green light” stop-and-go type games while hiking on the trails. Previous research suggests that repeated exposure to these types of tasks can improve inhibitory control in young children (Dowsett & Liversey, 2000).
When looking at working memory and inhibitory control, this study found equivalent growth between both preschool settings, which is similar to previous research (Faber-Taylor & Kuo, 2009; Ulset et al., 2017). Research shows that inhibitory control and working memory improve for children as they get older (Carlson, 2005; Gade et al., 2017; Kochanska et al., 2001); however, each skill may go through developmental “bursts” at different stages of development (Anderson, 2002). Some researchers have shown that working memory can be improved through specialized training (Green et al., 2012; St Clair-Thompson et al., 2010); others argue that previous studies have been too narrow and haven’t shown working memory training transferable to other tasks (Gade et al., 2017; Shipstead et al., 2012). It is possible that results reflect the particular aspects of executive function studied, as working memory may not be as malleable as previously thought (Rapport et al., 2013). If this is the case, then school setting might have less of an effect on the development of working memory when compared to other aspects of executive function, such as inhibitory control that is developing rapidly (Kochanska et al., 2001).
Unlike other areas of executive function, children in the nature-based program did not develop as many skills related to their behavioral self-regulation, which often involves integrating skills related to working memory, cognitive flexibility, and inhibitory control. This finding conflicts with other work in this area which finds preschool as a time of rapid growth in this area (McClelland et al., 2015), but can possibly be explained in several ways. It is possible that the structure of the nature-based program did not provide sufficient opportunities for children to develop behavioral regulation. Anecdotal evidence from the classroom observations suggested that behavioral self-regulation skills may have been more highly prioritized at the non-nature preschool. At the nature-based preschool, teachers allowed some children to wander away from group meetings to play independently (it is unclear from our observation if this was an allowance made to all the children or an instructional strategy for specific children). In contrast, teachers in the non-nature classrooms were more likely to redirect and manage these behaviors in ways that have been shown to improve executive function skills in children (Diamond & Lee, 2011; Webster-Stratton et al., 2008). It is possible that the structure of non-nature programs provides more opportunities for children to practice behavioral self-regulation skills. For example, at group meetings, children were encouraged to “sit still” and “use an inside voice.” Whereas children at the nature-based preschool spent the majority of class time outdoors where they were allowed to shout and run around, instead of practicing “indoor voices” as in the non-nature classrooms. The differences observed in this study could be due to the amount of time children were required to regulate their behavior.
It is also possible that the nature-based program missed opportunities to support behavioral regulation skill development within their classrooms compared to non-nature classrooms. For example, when many children wanted a turn with a specific toy (a common occurrence in both preschool programs), teachers at the non-nature program were observed creating a list with children to ensure that all children who wanted to play with the toy had a chance. This list was publicly displayed, and children were able to monitor it to see when it would be their turn. Visual prompts like this can be used to develop children’s behavioral self-regulation because they support their inhibitory control, independence, and self-direction (Kenworthy et al., 2014). Lists like this were not observed being utilized at the nature-based preschool, possibly due to limitations with the outdoor environment (e.g., materials needed to post a list outdoors are more extensive than in an indoor classroom).
These results were surprising as most research shows that unstructured play supports children’s behavioral self-regulation (Colliver et al., 2022; Savina, 2014; Sezgin & Demiriz, 2019). For example, a recent longitudinal study found that the amount of time children engaged in unstructured active play significantly predicted their behavioral self-regulation skills two years later (Colliver et al., 2022). While the current study found less growth in behavioral self-regulation for children who attended the nature-based preschool, it is possible that the benefits of unstructured play on self-regulation take longer to manifest and future work should examine the longitudinal impact of more time in nature for children. It is also possible that moving forward, nature-based preschools should take a “both/and” approach where there is a mix of unstructured nature play and structured instructional time. Recent empirical evidence has shown that children who attend nature preschool programs which take a more blended approach, where a program focuses on early academic skills but incorporates more unstructured nature play than a more traditional program, have significant positive effect on children’s executive function skills compared to children who attend a non-nature program (Ernst et al., 2022).
There is a wealth of data showing that behavioral regulation begins to show rapid, exponential growth around the age of three and a half (Chang et al., 2014; Clark et al., 2013; Montroy et al., 2016; Ponitz et al., 2009; Wiebe et al., 2012), yet many of the children in our study had behavioral regulation scores that decreased over the course of the school year. Approximately, 44% of children at the nature-based preschool decreased in their behavioral regulation skills compared to 14% at the non-nature preschool, which may speak to issues in the length of the assessment battery than the skill development. For example, field notes indicated that there was a higher refusal rate for testing in the nature-based programs during the spring (i.e., around 15%), when the weather was warmer at the assessment site. Even among those children who assented to be assessed, many were concerned that they were missing time outside during testing. Taken together, it is possible that children’s behavioral regulation scores on the nature-based program were detrimentally affected by the assessment process itself; thus, these findings should be interpreted with some caution.
Limitations and Future Directions
The current study provides an important initial comparison of child outcomes at a nature-based preschool compared to a non-nature preschool. We recognize, however, this was one nature-based preschool, which may not be representative of all nature-based preschools. In addition, this study saw a higher rate of refusal at the spring timepoint for children attending the nature-based preschool, compared to children attending the non-nature preschool. While possible reasons for this refusal were discussed previously in this paper, this could also represent assessment biases which future work should examine, while also being mindful of the length of the assessment battery and the order in which assessments are administered.
Several issues related to the generalizability of findings should be considered as part of the present work. First, the demographic make-up of the nature-based preschool was fairly homogenous. Future work should consider the impact these types of programs have on children from more racially and ethnically diverse populations, along with home and preschool settings (i.e., rural, suburban, or urban). Second, due to the small number of classrooms at each preschool site, this study was not able to look at classroom level effects. Future work should consider more classroom observation data to further examine the differences between each pedagogical approach and include multilevel analysis to account for the clustering of children within classrooms. Third, this study did not collect information on teachers’ pedagogical beliefs or year-round curriculum, which could be an important area for future study that can provide a more nuanced picture of the differences between nature-based and non-nature classrooms.
In addition, although the nature-based preschool spent a greater amount of time outdoors than the non-nature preschool, the difference in exposure to nature at both preschools may not have been as great as in previous research due to similarities in program quality and location. For example, the non-nature program incorporated natural materials throughout the indoor classroom and in activities (e.g., a small group activity was to have children paint with leaves). The non-nature preschool was in the process of getting their outdoor play area certified by Nature Explore™ (see D. L. Miller et al., 2013 for benefits of this type of play area). In contrast, previous studies that have investigated the effects of nature have done so with limited interactions with nature (Berman et al., 2008; Dadvand et al., 2015; Faber Taylor & Kuo, 2009; Schutte et al., 2017; N. Wells, 2000) or were correlational in nature (Kuo & Faber Taylor, 2004). The differences in growth could be more pronounced when comparing nature-based programs to non-nature ones with less access to nature.
Finally, future work should also consider whether additional time outdoors could benefit children in other ways such as in the development of gross and fine motor skills and emotional connections to the environment (Eick, 2011; Finch & Bailie, 2015; NAAEE, 2017). Work should be done to explore the longitudinal effects of these programs on children’s skills over time.
Conclusions
In light of current health and safety concerns, stakeholders are looking for alternative ways to engage young children in learning opportunities. One suggestion being considered is moving more classrooms outdoors (C. Inside-Outside, 2020). Administrators can take a lesson from well-established, high-quality nature-based programs. Not only have nature-based preschools been shown to spend significantly more time outside throughout the day, nature-based programs were shown to help children gain early literacy skills and some EF skills in ways that are similar to those situated indoors. As a wider variety of preschool programs are being offered, it is important to ensure that these programs are providing children with skills necessary for school readiness. Preschools set in nature, or in other unique settings, can support children’s development of these skills; however, educators need to be intentional to ensure children are developing the necessary skills needed in formal schooling.
Footnotes
Authors’ Note
The opinions expressed are those of the authors and do not necessarily represent views of the Storer Foundation or the U.S. Department of Education.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The research presented here was supported by grants from the Storer Foundation and the Institute of Education Sciences, U.S. Department of Education (R324A150063).
Note: This manuscript was accepted under the editorial team of Kara S. Finnigan, Editor in Chief.
Authors
ARIANNA E. PIKUS is an assistant professor in the department of Teaching, Learning and Culture at Texas A&M University; email:
LORI E. SKIBBE is a professor in the department of Human Development & Family Studies at Michigan State University; email:
RACHEL A. LARIMORE is the chief visionary at Samara Early Learning, Midland, MI 48640; email:
DAVID SOBEL, professor emeritus, Antioch University New England,