乘法估算中的策略转换成本

Strategy Switch Costs in Multiplication Estimation

灵活的策略转换是个体根据情境高效解决问题的重要能力之一。本研究分别在强制转换和自由转换两种范式下,探讨乘法估算中不同难度的策略转换是否需要转换成本。结果发现,个体使用两种不同难度的策略时均存在对称策略转换成本,且从较难策略转换到简单策略存在策略顺序困难效应。对称的策略转换成本中出现策略顺序困难效应,表明策略顺序困难效应与对称的策略转换成本可以共存。

To solve the problems in the present situation efficiently,one of the most important abilities of individuals is to flexibly use the strategy switching.The multi-strategy use facilitates one to flexibly alternate between different strategies,with the demands of problems and situations.Thus,two key issues with regard to cognitive strategies are:how the switching come strategies about and when switching strategies must be accompanied by switch costs.The present work contributes to solve these issues.It shows that participants obtain poorer performance when they use different strategies on two consecutive trials than when they use the same strategy in multiplication estimation in two different conditions.Arithmetic estimation competence,as an important part of the mathematical ability,cannot be replaced when solving problems.Estimating strategy is widely used when we make decisions.Therefore,exploring the switch costs for individuals between different strategies is important.It helps us to implement targeted training to improve individual mathematical cognitive ability.This can also be useful for normal development individuals to get a good learning ability about estimation.In this study,we used within-item paradigm in two kinds of situation.During the different-situation,we attempted to know when to start to switch strategies,and whether Chinese college students needed strategy switch cost,by double-digit multiplication estimate tasks.In two experiments,participants had to give approximate products to two-digit multiplication problems(e.g.,47×63).They were arranged for which strategy to use(Experiment 1)or they could choose among strategies(Experiment 2).It meant that Experiment 1 used the compulsive switching paradigm of strategy,in order to explore the strategy switch costs in the compulsive switching condition.In Experiment 2,we used the free switching paradigm,which could reflect the autonomy of individuals,in order to explore people’s ability of strategy switching and the cost of switching in the free strategy switching paradigm.For the participants,they had poorer performance when they used different strategies on two consecutive trials than when they used the same strategy in both the compulsive switching paradigm and the free switching paradigm.Therefore,they had symmetrical strategy switch costs.Furthermore,we also found strategy sequential difficulty effects during strategy execution:People were slower after having executed a difficult strategy than after having executed an easier strategy.It indicates that strategy sequential difficulty effects are not exclusively present in the asymmetrical strategy switch costs,and strategy sequential difficulty effects could be separated from the asymmetrical strategy switch costs.The results show that both strategy choices and strategy execution are influenced by problem and strategy characteristics,as well as by participants’working memory capacities.Under the condition of free strategy switching,participants can take the initiative to switch to the optimal strategy,reflecting that the individual has higher subjective initiative in the strategy transformation.We discuss possible processes underlying these strategy switch costs.Overall,this study focuses on strategy switch costs and it is expected to provide important information for the field of strategy switching.