The Spatial Bias Caused By Simple Addition And Subtraction Mental Arithmetic

The association between numerical and spatial has been the focus of numerical cognition domain.Previous studies mostly focused on the association between digital and space,such as,the findings of Spatial-Numerical Association of Response Codes effect.But studies about the relationship between complex number task(such as addition and subtraction mental arithmetic task)and space were relatively less.The existing studies about the association between addition and subtraction mental arithmetic and space found that spatial bias induced by mental arithmetic was related with spatial attention shifts on the mental number line.But the magnitude of operation results and semantic link between operation sign and space may affect spatial bias.Hence,the mechanism of spatial bias induced by mental arithmetic has not yet been revealed and need to be further explored.Besides,most previous studies required participants pressed the button to response with their hands.This response style was easy to form left-right pattern in space,and some related interferential variable with both hands movement may affect experimental results.Hence,the present study explored the associations between simple mental arithmetic and space through two experiments by eye tracker and tried to explore the mechanism of spatial bias induced by mental arithmetic and found suitable theoretical explanation.Experiment 1 explored whether addition and subtraction problems composed of single digit can induced spatial bias by means of eye movement response instead of pressing button,and further explored the time course of spatial bias.The results showed that addition and subtraction problems facilitated rightward and leftward eye movement respectively.Experiment 1 indicated that simple addition and subtraction mental arithmetic can induce the horizontal spatial bias.That is,addition mental arithmetic can facilitate the eyes move to rightward space,subtraction can facilitate the eyes move to leftward space.As a special digital symbol,zero doesn't have the nature of magnitude.Hence,based on Experiment 1,Experiment 2 select zero as operands to further explore the mechanism of spatial bias induced by mental arithmetic through Experiment 2A and Experiment 2B.Experiment 2 A select zero as the second operand aiming to explore whether spatial bias is related with spatial attention shifts on the mental number line or the semantic link between operation signs and space affects spatial bias.Experiment 2B select zero as the first operand aiming to further verify whether spatial bias is related with spatial attention shifts on the mental number line.The results of experiment 2A showed that addition and subtraction mental arithmetic which zero as the second operand didn't induce spatial bias.The results of experiment 2B showed that addition and subtraction mental arithmetic which zero was the first operand facilitated rightward and leftward eye movement respectively.Experiment 2 indicated that spatial attention shifts on the mental number line may have an influence on spatial bias induced by simple mental arithmetic.That is,when people represented mental arithmetic,they usually mapped number to the corresponding location of the left-to-right mental number line.They always locate the first operand,then shifts corresponding distance along the direction of results according to the magnitude of the second operand.The above mentioned results and discussions,the conclusion of this study are as follows:Simple addition and subtraction mental arithmetic can induce rightward and leftward spatial bias respectively.Spatial bias induced by mental arithmetic may be related with spatial shifts on the mental number line.