关键词: 双任务协调, 估算, 策略选择, 策略执行

Abstract:

Strategy is the way and the method of solving problems. Individuals use a variety of strategies when facing arithmetic problems. Strategy flexibility and adaptability is one of the key issues in the researching field of arithmetic cognition. Researchers postulate that central executive system affects the strategy using. For instance, the probability of individuals’ best strategy choice would be in decline and they would make more mistakes in strategy execution under the central executive load condition. Dual task coordination is an important part of the central executive system, reflecting the ability of reasonable allocation of alternation resources to select different processing modes and then to arrange the task processing sequence. Some studies found that the response was slower and less accurate in a dual task situation, and error rate increased. The way of stimulus presentation and reaction sequence affect dual task coordination. This study examined the impact of dual-task coordination on strategy use of computational estimation with two different dual task situations, and aimed at revealing the difference of individuals’ performance in different situations. Use the choice /no choice method, with 40 college students as participants, we investigated the influence of dual-task coordination on individual’s choice and execution of arithmetic estimation strategy. In ExpⅠ, arithmetic estimation task and letter task were presented simultaneously, with letter disappeared when presented after a certain time interval. The arithmetic problems disappeared in half of the trials. Participants were asked to firstly react to arithmetic task, then the reaction of letter task. On the contrary, in ExpⅡ, experimental design and materials were the same as ExpⅠ, but the only difference was participants must react to letter task firstly, and then react to arithmetic task. Dual-task situations had significant impact on individual’s strategy use. In the condition of arithmetic problems disappearing, participants had lower accuracies of both tasks, and they tended to choose the more simple rounding-down strategy. The accuracy of strategy execution was lower in the case of arithmetic problems disappearing. In addition, reaction order of task showed impact on strategy use. In the strategy execution condition, when participants were asked to first response to arithmetic task, dual task of different contexts affected the accuracy of their strategy executions; When first react to letters task, different situations affected both the reaction time and accuracy of individual’s strategy execution. In the strategy selection condition, different dual task situations had a greater impact on adaptive strategy choices in the condition of first reaction to letter task. In conclusion, dual-task coordination can affect individual’s strategy execution and choice, and the effect in the choice situation is greater than that of execution situation. The more difficult the situation is, the more the influence of dual-task coordination on strategy uses. Future research can combine with electrical technology as well as functional magnetic resonance imaging technology (fMRI) to further explore the changes of individuals’ electrical components or activated brain regions under different dual-task situations. Thus, it can provide certain neurophysiological evidences for the findings in the present study.

Key words: dual-task coordination, estimation, strategy choice, strategy execution