Poster #39 - The development of multiple non-symbolic ratio representations in children

• In Event: 3-106 - Poster Session 11
  In Poster Session: PS 11 Section - Cognitive Processes

Integrative Statement

Young children can rapidly extract quantity information from their environments, be it in terms of discrete or continuous dimensions (e.g. numerosity or line-lengths) – and they can do this even before they learn symbolic numbers. Converging studies suggest that the ability to process intuitive (or analog) magnitude is universal and functional early in development (e.g., Feigenson, 2007). This representation of magnitudes follows Weber’s law, whereby discriminability or perceptual acuity decreases as the ratio between compared magnitudes approaches 1. Several researchers have sought to chart the developmental trajectories of perceptual acuity for magnitudes of various types and formats (e.g. Odic, 2017).
However, some have called for research that foregrounds the role that perceptual sensitivity to ratio plays in magnitude processing (e.g. Sidney et al., 2017). Indeed, emerging research suggests that there is a primitive ability to process nonysmbolic ratio itself (e.g., ratios instantiated by juxtaposing two line segments, Figure 1) (e.g. Jacob, Vallentin & Nieder, 2012). Lewis, Matthews, and Hubbard (2015) dubbed this ability as the ratio processing system (RPS). However, existing RPS studies have mostly focused on adults and used limited types of ratio stimuli. Thus, there is little understanding of how the RPS develops in children or how different format influences RPS processing. We investigated the early development of ratio representations using nonsymbolic ratios in various formats.
We present data from sixteen preschool children, twelve 2nd graders, and twenty-two 5th graders from an ongoing study. Children completed a series of nonsymbolic ratio discrimination tasks, choosing the larger of two nonsymbolic ratios. Ratios were presented in four different nonsymbolic formats: dots, lines, circles, and irregular blobs (Figure 1). Due to the novelty of nonsymbolic ratios, all children received a brief PowerPoint lesson introducing the concept of nonsymbolic ratios prior to testing. To manipulate difficulty, the ratio between the ratios compared (i.e., the ratio of ratios) fell into one of 5 ratio bins (3:1, 2:1, 2:3, 3:4, and 5:6). Difficulty increased as the ratio between stimuli approached 1.
All children could make accurate ratio discriminations in various non-symbolic formats. Fifth graders were most accurate and preschoolers were least accurate (p = .008, Figure 2a). There was an effect of format (p <.0001), such that performance was highest with line ratios and lowest with dot ratios. We also found significant effects for ratio bins in all formats (p <.0001), whereby accuracy decreased as ratios become close (Figure 2b-d).
We found that children in each age group could accurately represent nonsymbolic ratios regardless of format tested. This was even true of children with no formal instruction on the concept of ratios or fractions. Children’s ratio representation also followed Weber’s law in all formats, consistent with findings among adults. These results demonstrate that children have perceptual access to the relationally defined ratio magnitude. Future work will explore the relations between simple magnitude acuity (e.g. typical ANS discrimination) and acuity for ratios made from pairs of simple magnitudes.

Authors

• Yunji Park, University of Wisconsin-Madison
  Presenting Author

• Alexandria A. Viegut, University of Wisconsin - Madison
  Non-Presenting Author

• Percival Matthews, University of Wisconsin-Madison
  Non-Presenting Author