Influences of task and notation on symbolic numerical cognition
Authors:   , Wong Becky 
Published: November 2024

In the world around us, symbolic numbers occur in different notations such as Arabic numerals (e.g., “4”) and number words in different languages such as English (i.e., “four”) and Chinese (i.e., “四”). Through education and cognitive development, humans are able to engage symbolic numerical cognition, which is the ability to represent and process numerical information about magnitude (i.e., quantity) and order (Gilmore et al., 2018) for symbolic numbers. Currently, the factors that influence the representation and processing of symbolic numbers are under theoretical and empirical debate. This thesis investigated the influences of task and notation on symbolic numerical cognition over a series of three related studies. Study 1 examined the influences of task and notation on the processing of numerical magnitude. In this behavioural study, adults who showed a balanced profile of language dominance in English and Chinese completed intentional and non-intentional tasks of magnitude processing. The results revealed that magnitude processing is dependent on task and occurred primarily under intentional task conditions. Additionally, magnitude processing was found to be independent of the notation in which the stimuli were presented. Study 2 investigated the influences of notation and direction on the processing of numerical order. In this behavioural study, adults who were bilingual in English and Chinese completed an intentional task of order processing. The numbers were presented in ascending/descending order, or in a mixed direction. The results indicated that order processing is dependent on direction and occurred for ascending/descending trials only. Order processing was also found to be independent of the notation in which the stimuli were presented. In addition, better order performance among numbers presented as Arabic numerals was significantly associated with higher mathematical achievement. Study 3 examined the influence of notation on the representation and processing of symbolic numbers. In Experiment 1, adults who showed a balanced profile of language dominance in English and Chinese completed a task of non-intentional numerical processing, the fMRI numerical adaptation paradigm. In Experiment 2, the same participants completed a task of intentional numerical processing, the behavioural larger/smaller than 5 task. The overall pattern of behavioural and neuroimaging data suggested that the representation and processing of number symbols was dependent on task and occurred under intentional task conditions only. Across the studies, the behavioural data consistently revealed that task, rather than notation, influences symbolic numerical cognition. However, the brain imaging data in Study 3 suggested that a notation dependent account for the neural representations of number symbols cannot be conclusively excluded. Furthermore, although notation did not generally affect the nature of magnitude or order processing for symbolic numbers, the data indicated that notation influences overall performance in tasks of numerical processing. Specifically, performance for numbers presented as Arabic numerals was consistently better than for number words. Together, the findings in this thesis contribute to current theoretical and empirical understandings regarding the influences of task and notation on magnitude and order processing for symbolic numbers and how this information is represented in the human brain.