Sex differences in number line estimation depend on solution strategies applied

Sex differences in mathematical performance have frequently been examined over the last decades indicating an advantage for males in many domains especially when numerical problems cannot be solved by (classroom-)learnt strategies and/or estimation. Even in basic numerical tasks such as number line estimation, males were recently found to outperform females (Bull et al., 2013) - with sex differenced argued to emerge from different solution strategies applied. To better understand the processes underlying sex differences regarding the spatial representation of number magnitude we used two versions of the number line estimation task, which are assumed to be solved by different strategies: a bounded version with start and endpoint as well as an unbounded version with only the start point and a predefined unit given. Assuming that women tend more strongly to apply known procedures we expected them to be at a particular disadvantage in the unbounded number line estimation task which is less prone to be solved by specific strategies such as proportion judgement but requires more pure numerical estimation. In line with our expectations results indicated more pronounced sex differences for unbounded number line estimation indicating that males performed reliably more accurately than females in this task version. This further adds to recent evidence suggesting that estimation performance in the bounded task version may reflect solution strategies rather than numerical estimation. Additionally, it indicates that gender differences regarding the spatial representation of number magnitude may not be universal, but associated with the solution strategies applied.