Development of Critical Thinking in Pre-Service Early Childhood Education Teachers Using Scientific Inquiry Practices in STEM Projects

Critical thinking (CT) is increasingly recognized as a transversal competence within STEM education, yet it is often addressed implicitly in preservice teacher training. This study analyzes the development of critical thinking in 130 Preservice Early Childhood Education Teachers (PECETs) who, during the 2024–2025 academic year, participated in a training programme designed from a STEM perspective and grounded in scientific inquiry. A mixed-methods approach was used to examine the teaching unit elaborated by PECETs with a rubric that assessed stages of inquiry, as well as to analyze their final reports for evidence of connections between CT and STEM. The findings revealed strong scientific thinking but only superficial links to STEM and CT suggesting progress in participants’ scientific reasoning and analytical and reflective competence. However, evidence of explicit STEM integration and CT justification remained limited. These results confirm the formative potential of inquiry-based STEM education for supporting CT development in early childhood preservice teacher education, while highlighting the need for more explicit scaffolding of inquiry phases, structured reflection opportunities, and collaborative argumentation tasks to strengthen conceptual integration and deepen critical engagement with scientific evidence.