The strategy matters: Bounded and unbounded number line estimation in secondary school children

• Published in: Cognitive development 2020-01, Vol.53, p.100839, Article 100839
• Main Authors: Jung, Stefanie, Roesch, Stephanie, Klein, Elise, Dackermann, Tanja, Heller, Juergen, Moeller, Korbinian
• Format: Article
• Language: English
• Subjects: Basic arithmetic skills; Cognitive science; Development of number magnitude representation; Education; Humanities and Social Sciences; Number line estimation; Proportion-judgment strategy; Psychology; Secondary school
• ISSN: 0885-2014; 1879-226X
• DOI: 10.1016/j.cogdev.2019.100839

Changes in number line estimation (NLE) performance are frequently used as an indicator for the development of the number magnitude representation. For this purpose, two different task versions have been applied: a traditional bounded and a relatively new unbounded NLE task. Previous studies mainly assessed primary school children or adults showing that these tasks differ in terms of i) estimation accuracy and solution strategies employed as well as ii) with respect to their relation to other basic numerical/arithmetic skills. So far, data from secondary school children are scarce for bounded NLE, and even no data is available for unbounded NLE. Thus, we assessed bounded and unbounded NLE in grade levels 5–7 to evaluate a) developmental as well as strategic influences, and b) the relation of bounded and unbounded NLE performance with basic arithmetic skills. Our results show that children employed the use of different solution strategies for bounded (i.e., proportion-judgement) and unbounded (i.e., magnitude-estimation based) NLE. Moreover, only for bounded NLE, estimation accuracy increased with age. Furthermore, estimation performance for bounded but not unbounded NLE was strongly associated with basic arithmetic (addition, subtraction, multiplication, and division). Our findings indicate that the differential results for bounded and unbounded NLE obtained in primary school children seem to generalize to older secondary school children. Presented results substantially contribute to the knowledge about the (consecutive) development of skills pertaining to bounded and unbounded number line estimation.