Estimation of magnitudes and numerosity in different formats of stimulus presentation: the numerical ratio effect

Abstract

Introduction. Several researchers discuss the possibility of existence of a common mental system responsible for the estimation of both discrete numerosities and continuous magnitudes. The numerical ratio effect observed during comparison tasks is one of the evidences of an existence of such system. It manifests itself in an increase in response time and a decrease in accuracy as the numerical proportion between the compared arrays of objects or magnitudes increases. This study investigated the numerical ratio effect for different types of tests and stimulus presentation formats in order to explore the interrelationships between systems of magnitude and numerosity estimation. Methods. The sample consisted of 83 students (20% were men, the average age was 20.34 years). The participants of the study performed nonsymbolic comparison tasks, arears comparison task and comparison of nonsymbolic quantity with symbolic numbers task (nonsymbolic – symbolic comparison test). Two formats of stimulus presentation were used during the nonsymbolic comparison test: separate/homogeneous and mixed/heterogeneous. The accuracy of estimation and numerical ratio effect were calculated for each test. Results. The numerical ratio effect was significant in the nonsymbolic comparison tests (for both formats of stimulus presentation) and in the nonsymbolic-symbolic comparison test, but was not significant in the areas comparison test. Numerical ratio effects for different tests do not correlate with each other. It was also shown that the accuracy of the estimation of magnitudes correlates with the results of the nonsymbolic comparison test, and this relationship was stronger for the mixed/ heterogeneous format. Discussion. Results of this study demonstrated that the relationship between magnitude and discrete numerosity estimation systems can vary under different conditions of stimulus presentation. It makes possible to refine the existing theoretical models describing functioning of the Approximate Number System. The obtained results cannot be fully explained by the theory of a unified numerosity/magnitude estimation system. It was shown, however, that the magnitude estimation system does in fact contribute to the estimation of discrete numerosity.

Keywords

• оценка величин
• оценка размеров
• оценка количества
• чувство числа
• несимволическая репрезентация
• эффект пропорции
• эффект конгруэнтности
• визуальные параметры
• несимволическое сравнение
• формат предъявления