Spatial discontinuity between causes and effects is a feature of many scientific concepts, particularly those in the environmental and ecological sciences. Causes can be spatially separated from their effects by great distances. Action at a distance, the idea that causes and effects can be separated in physical space, is a well-studied concept in…

Developmental predictors of children's fraction concepts and procedures at the end of fourth grade were investigated in a 2-year longitudinal study. Participants were 357 children who started the study in third grade. Attentive behavior, language, nonverbal reasoning, number line estimation, calculation fluency, and reading fluency each…

Most children who are congenitally deafblind are severely delayed in their communication development and many will not achieve symbolic understanding and expression. This article discusses developmental markers cited in the research literature as predictive of or facilitative of the development of symbolism. These markers include the growth toward…