Play is an integrative process, and the skills acquired in it—overcoming impulses, behavior control, exploration and discovery, problem-solving, reasoning, drawing conclusions, and attention to processes and outcomes are foundational cognitive structures that drive learning and motivation. Loose parts play is a prominent form of play that many scholars and educators explicitly endorse for cognitive development (e.g., divergent thinking, problem-solving). It is unique among play types because children can combine different play types and natural or manufactured materials in one occurrence. While educators and policymakers promote the benefits of loose parts play, no previous research has explored the direct relationship between preschool-age children’s indoor loose parts play experiences and cognitive development. We address this gap by bringing together the relevant literature and synthesizing the empirical studies on common play types with loose parts, namely object and exploratory, symbolic and pretend, and constructive play. We also focus on studies that examine children’s experiences through loose parts, highlighting the impact of different play types on learning through the reinforcement of cognitive skills, such as executive function, cognitive self-regulation, reasoning, and problem-solving. By examining the existing literature and synthesizing empirical evidence, we aim to deepen our understanding of the relationship between children’s play with loose parts and its impact on cognitive development. Ultimately, pointing out the gaps in the literature that would add to the body of knowledge surrounding the benefits of play for cognitive development and inform educators, policymakers, and researchers about the significance of incorporating loose parts play into early childhood education.

Children’s engagement with toys and play materials can contribute to the foundational cognitive processes that drive learning. Loose parts are interactive, open-ended materials originally not designed as toys but can be incorporated into children’s play (e.g., acorns, cardboard, and fabric). Practitioners and researchers widely endorse loose parts for fostering creativity, divergent thinking, and problem-solving skills. Despite these recommendations, research on their specific role in young children’s cognitive development remains limited. This systematic review examines how indoor loose parts play has been studied in relation to young children’s (0–6 years) cognitive development. Following PRISMA guidelines, searches in bibliographic databases and forward and backward citation tracking identified 5721 studies published until December 2024. We identified 25 studies and evaluated the quality and risk of bias. Studies focused on children’s general cognitive outcomes, language development, and specific cognitive subdomains, with many reporting positive associations between children’s play materials and cognitive development. However, five studies found no such associations, and another seven did not address the relationship between play materials and outcomes. Despite methodological variation across studies, our systematic review identified a relationship between play materials similar to loose parts and children’s problem-solving, creativity, academic skills (reading and math), and both convergent and divergent thinking. Notably, only one study explicitly used the term “loose parts.”Our review identified empirical and methodological gaps regarding the relationship between play materials and cognitive development, which can inform future research.

What is the foundational knowledge that children rely on to provide meaning as they construct an exact symbolic number system? People and animals can quickly and accurately distinguish small exact quantities (i.e., 1 to 3). One possibility is that children’s ability to map small quantities to spoken number words supports their developing exact number system. To test this hypothesis, it is important to have valid and reliable measures of the efficiency of quantity-number word mapping. In the present study, we explored the reliability and validity of a measure for assessing the efficiency of mapping between small quantities and number words – speeded naming of quantity. Study 1 (N = 128) with 5- and 6-year-old children and Study 2 (N = 182) with 3- and 4-year-old children show that the speeded naming of quantities is a simple and reliable measure that is correlated with individual differences in children’s developing numeracy knowledge. This measure could provide a useful tool for testing comprehensive theories of how children develop their symbolic number representations.

Children incorporate items found in their environment into their play, transforming everyday objects and materials into an opportunity for exploration. Termed loose parts, these versatile, natural, or manufactured materials (e.g., cardboard, pipes, buttons, sticks) are widely recommended for supporting children’s early STEM learning. Limited empirical work has documented children’s indoor STEM behaviours with loose parts. Using a within-subjects experimental design, we examined children’s early STEM behaviours and engagement ( N = 60; 32 females, 28 males; Mage = 58.6 months, SD = 10.9) during unstructured solitary play with loose parts and toys that have limited function and affordance (e.g., toy percussion instruments; control). We conducted observations of children’s STEM behaviours. Children’s cognitive functioning, executive function, and home learning environment were also assessed via standardized measures and parent reports. Children demonstrated significantly more STEM behaviours with loose parts than in the control condition. There was no credible evidence that these behaviours differed by sex. Cognitive functioning predicted STEM Engagement Score with loose parts, with children’s verbal comprehension being the strongest predictor in the control condition. Children’s executive function and parents’ attitudes regarding play and engagement in play activities at home predicted constructing structures, which were the most common STEM behaviours. This study thus demonstrates that loose parts may offer a powerful opportunity for STEM-related early learning; however, children’s cognitive capacities and home experiences should be considered, rather than assuming uniform benefits.

Mounting longitudinal evidence demonstrates that young children's numeracy knowledge before kindergarten determines their mathematics achievement path in primary grades and high school graduation. Mathematics education and children's play do not have to be binary and compete for time in early learning and childcare learning environments. Indeed, researchers demonstrate that play and planned mathematical activities enrich one another and ultimately contribute to children's learning outcomes. Guided play, in which educators combine planned learning experiences with the child-directed nature of play, focuses on learning outcomes through adult scaffolding. This chapter synthesizes research on how play experiences can be an organic but powerful process for scaffolding and elevating young children's mathematical understanding in light of current evidence from early numeracy research. In the conclusion of this chapter, evidence-based recommendations are introduced for facilitating children's developing numerical competencies and activating existing knowledge through guided play.

Children incorporate what they find in their environment into their play, transforming everyday objects and materials into creativity and exploration. Termed loose parts, these versatile, natural or manufactured materials (e.g., cardboard, pipes, buttons, beads) are widely recommended for supporting young children’s early STEM engagement. While engaging, there is limited empirical work documenting young children’s indoor STEM behaviours through direct observation. Foundational research is needed to delineate how children’s cognitive capacities, home learning environment, and STEM engagement interact during early play to inform more targeted and developmentally grounded STEM education in early years. Using a within-subjects experimental design, we examined children’s STEM behaviours and engagement (N = 60, 32 girls, M = 58.6 months, SD = 10.9) during unstructured solitary play with loose parts and with toys with limited function and affordance (i.e., toy percussion instruments, control). Children’s cognitive functioning, executive function, and home learning environment were assessed via standardized measures and parent reports. Children demonstrated significantly more STEM behaviours with loose parts, particularly constructing, exploring mathematical concepts, communicating intentions, and reasoning about how things work. These behaviours did not differ by sex. Linear regression analyses showed that cognitive functioning predicted STEM engagement with loose parts, while verbal comprehension was the strongest predictor in the control condition. Construction behaviours were the most common STEM behaviours. Parents’ attitudes toward play and children’s executive functioning predicted construction behaviours. Findings underscore the importance of aligning play-based learning environments with children’s cognitive profiles and home experiences, rather than assuming uniform benefits from loose parts across all children.