Exploring the interface between number words and perceptual magnitudes

As humans, we reason about quantity in at least two distinct ways—through our intuitive, approximate perception of quantity and through precise number words. With sufficient development, these two systems interface and interact, allowing us to make quick judgments with crude precision (e.g., how many items are in our shopping basket). To date, two theories have been proposed to explain the underlying mechanism of this interface between perception and language. Under the first—the associative mapping theory—children create item-specific associations between particular number words (e.g., “ten”) and the perceptual representations that they most frequently experience. While under the second—the structure mapping theory—children map number words to their perceptual representations by realizing the inherent similarity in the representational structure of the two systems (e.g., both are linear dimensions where higher values represent more/greater amounts). Existing literature has almost exclusively focused on understanding how children create this interface in one domain of quantity (i.e., number), leaving the critical question of how children map number words to other, non-numeric domains of quantity (e.g., length, area) entirely open. This thesis explores when and how children map number words to a broader spectrum of quantities by examining their estimation abilities in number, length, and area. We find that while the perception of number, length, and area are largely independent of each other, estimation accuracy and variability are tightly linked and show a similar age of maturity, supporting the structure mapping account. These results are discussed in the broader context of how language and perception interact and change with development.Arts, Faculty ofPsychology, Department ofGraduat