This article defines the concepts related to symbolic and sign representations, cognition and learning in the early years. The first study experiment of teaching 33 preschool children (19 boys and 14 girls; M = 68, 5 months) the notion of rainbow phenomenon proved the equal effectiveness of the use of both sign and symbolic tools. The second study experiment of teaching 49 schoolchildren (23 boys and 26 girls; M = 102 months) the complex notion of a mathematical function furthered our understanding of the impact of sign and symbolic tools and showed that the use of symbolic tools (metaphors and imagery) as mediators for successful transference to sign representation is effective for children who otherwise experience difficulties mastering new and complex content. The authors discuss the importance of children's play in the early years as a space where children experience and acquire operations with symbols, and the role of symbolic tools in transference to sign representation. The article furthermore provides considerations regarding the challenges and potential policy directions suggested by these research findings.