Number comparison and number ordering as predictors of arithmetic performance in adults: Exploring the link between the two skills, and investigating the question of domain-specificity

ABSTRACT

Recent evidence has highlighted the important role that number-ordering skills play in arithmetic abilities, both in children and adults. In the current study, we demonstrated that number comparison and ordering skills were both significantly related to arithmetic performance in adults, and the effect size was greater in the case of ordering skills. Additionally, we found that the effect of number comparison skills on arithmetic performance was mediated by number-ordering skills. Moreover, performance on comparison and ordering tasks involving the months of the year was also strongly correlated with arithmetic skills, and participants displayed similar (canonical or reverse) distance effects on the comparison and ordering tasks involving months as when the tasks included numbers. This suggests that the processes responsible for the link between comparison and ordering skills and arithmetic performance are not specific to the domain of numbers. Finally, a factor analysis indicated that performance on comparison and ordering tasks loaded on a factor that included performance on a number line task and self-reported spatial thinking styles. These results substantially extend previous research on the role of order processing abilities in mental arithmetic.

KEYWORDS:

• Arithmetic skills
• distance effect
• mental number line
• number comparison
• number ordering

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Kinga Morsanyi http://orcid.org/0000-0002-7550-1454

Notes

1. In the following, we focus exclusively on symbolic comparison tasks (and do not discuss distance effects on the dot comparison task further). Besides methodological issues regarding the dot comparison task (e.g., Fuhs & McNeil, 2013; Gilmore et al., 2013; Szűcs et al., 2013), another reason for this is that recent findings have questioned whether distance/ratio effects in the case of symbolic and non-symbolic comparison reflect similar processes (Lyons et al., 2015).

2. Although our study did not include an examination of the SNARC effect, we believe that the general issues that we raise in these sections are highly relevant to our investigation.

3. Extreme items within each triad are the items that have the greatest distance between them when the items appear in the correct order (e.g., in the case of 2, 7, 4, the extreme items are 2 and 7, and the distance between them is 5). Thus, a distance of 2 means that the numbers were adjacent.

4. All number and month triads used in the study are listed in Table A in the Appendix.

5. A stepwise regression analysis where the number and month comparison and ordering tasks were used as predictors of arithmetic performance yielded the same result, retaining the number-ordering and number comparison tasks as significant predictors of arithmetic performance and excluding the month-ordering and month comparison tasks.

6. Using number comparison as the mediated variable is in line with developmental findings (Lyons et al., 2014). Whereas, in the case of young primary school children, number comparison performance is the best predictor of maths skills, in higher grade children, number ordering becomes the strongest numerical predictor of maths skills. Given that ordinal processing becomes more important than comparison skills with development, it is an important question whether, in the case of adult participants, comparison skills have any independent predictive value after their shared variance with ordering skills is taken into consideration.

7. This can be considered as additional evidence that months were not converted into numbers by participants.