The Influence Of Working Memory Span On Adult's Computational Estimation Strategy Choices

Number processing and mathematical calculation is a field of research with a growing interest in cognitive neuroscience. One of the most fascinating findings in the area of arithmetic processing is that people use several strategies to solve problems. Some new technologies, such as EEG, fMRI and ERP, are widely used as the objective and effective research means. Especially, the ERPs technology is a valuable means to research cognitive processes (eg. perception, attention and memory) and cognitive functions. Arithmetic estimation strategy in event-related brain potentials will become a new research trend in cognitive neuroscience. But the researches of adult arithmetic estimation and strategy selection was few, especially that using ERP technology. The current study investigated whether working memory capacity is directly correlated with adult's strategy selection, and it is good to further understand the brain mechanism and intrinsic mechanism of strategy selection. The study explores the estimation strategies in complex multiplication tasks using both behavioral experiments and event-related brain potentials (ERPs).The results showed that,(1)Among four conditions, there were no significant differences in RTs and the correct percents between high-working memory and low-working memory individuals.(2) As far as strategy execution is concerned, in no-choice condition, there were no significant differences of the accuracy between the conditions of rounding-up and rounding-down. There were no significant differences of the RTs between the conditions of rounding-up and rounding-down, neither in low-working memory individuals nor in high-working memory individuals.(3)From the perspective of the adaptivity of estimation strategy, there were no significant difference in the adaptivity of estimation strategy between high-working memory and low-working memory individuals. But, in choice-condition and the best-condition, both low-working memory individuals and high-working memory individuals were inclined to using the rounding-down strategy, but low-working memory individuals used more rounding-down strategy than the high-working memory individuals.(4) The results from the ERP experiment showed that in the 0-300 time window, the ERPs elicited in the three experimental conditions(rounding-up, rounding-down, and choice condition) didn't have any differences either in high-or in low-working memory subjects. It suggests that there's no difference in the encoding stage. The ERPs showed difference in 300-1200ms, which indicates that three experimental conditions do have different processing procedures in both groups. In other words, the strategy selection and strategy execution process of the three conditions is different.To sum up, the following conclusions were drawn:(1) Working memory span may be not significantly affected adult's strategy selection. The strategy conditions may be the main factors of adult's strategy selection.(2)The ERP differences in 300-1500ms indicate that adult's computational estimation strategy selection and strategy execution occurred in this time window. In the process of strategy selection, the brain regions transform frontal zone to top area. The areas activated in low-working memory and high-working memory individuals had no significant difference.