Poster E122, Monday, March 27, 2:30 – 4:30 pm, Pacific Concourse
The Conversion across Magnitude and Rank Forms of Numerical Representation
Mei-Jing Lin1, Erik Chihhung Chang1; 1National Central University, Taiwan
The current FMRI study aimed to examine the conversion between the magnitude and rank forms of numerical representation and the corresponding neural mechanisms. Two groups of participants performed visual parity judgments by making spatial and non-spatial responses before receiving hypnotic suggestions that either manipulated magnitude or rank representations, respectively. The behavioral results showed a significant interaction between the type of suggestion and response under the manipulated magnitude condition, indicating that seeing a number line easily elicits the magnitude representation, yet thinking of the magnitude of numbers does not directly elicit the spatial numerical mapping. The linkage between numbers and spatial response was correlated with the activation in the right superior frontal area and left angular gyrus under the manipulated magnitude suggestion, and in the right dorsolateral prefrontal cortex under the manipulated rank suggestion. Conversely, the linkage between numbers and non-spatial response was correlated with the activation in the left ventral intraparietal area under the manipulated magnitude suggestion, and in the right intraparietal sulcus, left ventrolateral prefrontal cortex and left posterior intraparietal sulcus under the manipulated rank suggestion. These findings indicate that: (1) even though the rank and magnitude forms of a number are often associated, they may share distinct features; (2) the magnitude form of numerical representation is stronger than the rank form and is more likely the default concept representation. Taken together, we suggest that how numbers are represented depends on both task demands and individual differences in the cortical mapping between response and numerical forms.
Topic Area: PERCEPTION & ACTION: Vision