Seeing Flames, Perceiving Quantity: Approximations of Fire Intensity Across Development.

Between three and six years of age, children become better able to detect smaller differences in non-symbolic visual quantities. This includes judging which set of objects are greater in number and area. These findings suggest that the underlying approximate magnitude representations, which facilitate the estimation of these quantities, become more precise with age into adulthood. Such parallels in developmental trends raise questions about the extent to which they are observed across different non-symbolic quantities. The present study addressed this question using a novel quantity: visual fire intensity. Like number and area, fire intensity can be estimated using visual cues and has real-world implications. However, it is unclear whether young children accurately compare fire intensities and if there are age-related differences in performance. The present study investigated the developmental trend of young children's visual perception of fire intensity. Over 70 three- to six-year-olds completed a comparison task where they judged which of two train engines had a more intense fire. Based on non-symbolic quantity research, the ratio (relative difference) between the intensity of two simulated fires was varied across trials to be smaller versus larger. Significant ratio and age effects were observed: children were more likely to select the train with the greater-intensity fire as being 'more' the larger the ratio and the older the child. These results suggest that young children are sensitive to differences in fire intensity using visual cues and have increasingly precise estimates by six years of age. This developmental pattern indicates that approximate magnitude representations support perceptions of ecologically relevant, dynamic quantities such as fire intensity.