Number Sense Mediates Sex Differences in the Use of Advanced Arithmetic Strategies

• In Event: Development of Number Sense

Abstract

Critical to arithmetic learning is the acquisition of efficient computational strategies because advanced strategy choice explains differences in accuracy (Laski et al., 2016) and also predicts long-term math outcomes above and beyond accuracy (Casey et al., 2017; Geary, 2011; Torbeyns et al., 2005). Prior research has identified “decomposition,” in particular, as an advanced arithmetic strategy and a powerful predictor of long-term mathematics outcomes. Decomposition, involves transforming a problem into simpler ones using known number facts (e.g., 7+5 = (7+3)+2 = 10+2 = 12). There is some evidence suggesting sex differences favoring males in the use of this advanced strategy. This evidence, however, is confounded as researchers have often lumped different strategies in the “advanced” category (Gaidoschik, 2012; Carr & Alexeev, 2011). Further, little research has investigated how sex differences in the use of arithmetic strategies might be related to sex differences found in other math skills. One consistent early sex difference is that boys have greater numerical magnitude skills, as measured by the number line estimation task (Gunderson et al., 2012; Hutchison et al., 2019; LeFevre et al., 2010; Reinert et al., 2017; Tian et al., 2022). The present research investigated whether sex differences in the use of decomposition strategy are mediated by sex differences in numerical magnitude skills.

Methods
To address this question, we studied two different samples of first-graders, one from the US and the other from Russia. Both studies assessed the use of decomposition strategies and accuracy on the addition and subtraction problems and included a number line measure to assess number magnitude. Study 1 included 96 US first-graders (53% girls); Study 2 included 210 Russian first-graders (49% girls).

Results
The two studies showed parallel results: boys produced more accurate numerical magnitude estimates on the number line task and used decomposition more frequently on the arithmetic task. To test our mediation hypotheses, we conducted bias-corrected bootstrapping mediation analyses. Critically, both studies provided support for the meditation hypothesis, demonstrating partial mediation in Study 1 with lower-income US urban first-graders (see Figure 1) and complete mediation in Study 2 with first-graders from a large Russian city (see Figure 2).

Discussion
The current investigation confirmed the existence of sex differences in numerical magnitude knowledge as measured by the number line task. This finding is consistent with a large body of research documenting a male advantage in number line estimation (Gunderson et al., 2012; Hansen et al., 2015; Hutchison et al., 2019; Tian et al., 2022). Compared to numerical magnitude knowledge, sex differences in the use of decomposition have not been as thoroughly investigated in prior research. For the first time, the present study showed that sex differences in advanced arithmetic strategy use are mediated by numerical magnitude knowledge. Importantly, this pattern was demonstrated across different cultural contexts and levels of performance. The mediation finding is an important step toward identifying a potential causal relation. It raises the possibility that the sex differences in decomposition strategy use emerge, at least in part, because of differences in numerical magnitude knowledge.

Authors

• Marina Vasilyeva
  Presenting Author

• Elida V Laski

• Beth M Casey, Boston College

• Linxi Lu, Boston College

• Muanjing Wang, Boston College

• Hyun Young Cho, Boston College