The development of scientific reasoning in preschoolers: hypothesis testing, evidence evaluation and argumentation from evidence

Although research on scientific reasoning has shown that young children have poor skills in epistemic activities such as evidence evaluation or experimentation; recent research demonstrated that they have powerful learning mechanisms in making causal predictions from evidence patterns or performing experiments to reveal causal relations that are not readily available to them. Although these abilities are informative concerning early epistemic activities, little is known about whether young children can reason scientifically. The ability to coordinate hypotheses and evidence; and having a metacognitive understanding of the hypothesis–evidence relation are the two foundational abilities for scientific reasoning. In three empirical studies, the present thesis investigated the development of these two abilities in 4- to 6-year-old preschoolers in three epistemic activities; namely, hypothesis testing, evidence evaluation, and argumentation from evidence. Study 1 showed that older preschoolers can differentiate between epistemic goals of hypothesis testing and practical goals of effect production, which suggest that the epistemic categories of hypotheses and evidence; and the ability to coordinate the two is already present in the late preschool years. Study 2 revealed that preschoolers can generate disconfirming evidence in order to refute false causal claims and they can reflect on the relation between beliefs and evidence. Study 3 showed that 5- and 6-year-olds can reflect on the relation between their knowledge states and confounded evidence. The findings of the three studies suggest that the foundational abilities for scientific reasoning, understanding the inferential relation of hypothesis and evidence and the reflective ability over this relation are present in preschoolers