How do visual abilities relate to each other?
In vision, there is, surprisingly, very little evidence of common factors. Most studies have found only weak correlations between performance in different visual tests; meaning that, a participant performing better in one test is not more likely to perform also better in another test. Likewise in ageing, cross-sectional studies have repeatedly shown that older adults show deteriorated performance in most visual tests compared to young adults. However, within the older population, there is no evidence for a common factor underlying visual abilities. To investigate further the decline of visual abilities, we performed a longitudinal study with a battery of nine visual tasks three times, with two re-tests after about 4 and 7 years. Most visual abilities are rather stable across 7 years, but not visual acuity. I will discuss possible causes of these paradoxical outcomes.
How Children Discover Mathematical Structure through Relational Mapping
A core question in human development is how we bring meaning to conventional symbols. This question is deeply connected to understanding how children learn mathematics—a symbol system with unique vocabularies, syntaxes, and written forms. In this talk, I will present findings from a program of research focused on children’s acquisition of place value symbols (i.e., multidigit number meanings). The base-10 symbol system presents a variety of obstacles to children, particularly in English. Children who cannot overcome these obstacles face years of struggle as they progress through the mathematics curriculum of the upper elementary and middle school grades. Through a combination of longitudinal, cross-sectional, and pretest-training-posttest approaches, I aim to illuminate relational learning mechanisms by which children sometimes succeed in mastering the place value system, as well as instructional techniques we might use to help those who do not.