Strategy Switching Costs And Its Processing Mechanism In Mathematic Estimate

Flexible strategy switch is an important condition for individuals to solve tasks effectively. In daily life, the strategies switching examples are everywhere. So how the strategies switching come about? Whether person can switch from each strategy on his/her own initiative? In the strategy switching occur, what kind of work the brain to do? When switching strategies must be accompanied by a switching cost? And what is the difference between switching strategies and repeating a strategy? With these problems, this study made the following experiments:In this study, we used within-item paradigm in two kinds of situation. In different situation, we wanted to know when started to switch strategies, Chinese college students whether need strategy switching cost, as well as the strategy switching processing mechanism, by double-digit multiplication estimate tasks. This research consists of two experiments, discussing strategies switching and its cost from behavior and EEG date respectively. Experiment one combines the compulsive switching paradigm of strategy and the within-item task switching paradigm, in order to explore the strategy switching processing mechanism in the compulsive switching condition. In the experiment two, we combined the free switching paradigm and the within-item task switching paradigm, which can reflect the autonomy of individuals, in order to explore persons’ ability of strategy switching, the cost of switching and its processing mechanism characteristics in the free strategy switching paradigm. The results showed:(1) Strategy switching and strategy switching cost were not necessarily relationship,both of them could be separated. That was to say, when the strategy switching occur, the switching cost was not produced necessarily. In the research, both in the compulsive switching condition and the free strategy switching condition, switching from the difficult strategy to simple strategy required switching cost, but from the simple strategy to difficult strategy transformation need no strategy switching cost.(2) Although in both conditions only from difficult strategy into simple strategy exists switching cost, but different conditions, different switching costs. In the compulsiveswitching condition, the switching cost from difficult strategy to simple strategy was appeared in two main time windows: 0 – 200 ms and 200 – 550 ms; And in the free strategy switching paradigm, the switching cost from difficult strategy to simple strategy was appeared only in 0 – 200 ms. These suggested that there is lasted longer conflict in the compulsive switching condition, that is, conflict not only exists in the strategy choice ——according to the clues to implement strategy and participants might want to choose the strategy, but also exists in the execution of strategy, namely the conflict of the participants may produce the existing strategy and enforce the strategy. But under the condition of free strategy switching paradigm, the strategy switching cost only appeared in strategy selection stage, has nothing to do with the strategy implementation phase.(3) Although switching costs between the two strategies were different, the strategy switching processing mechanisms from each other were the same. However the consistency of these strategy switching processing mechanisms was not across different conditions, namely, under the compulsive switching condition, the strategy transformation mechanism is different from that under the free switching strategy condition. These were mainly embodied in the difference of brain activity areas. Although under the both conditions, brain activity areas are in parietal lobe, but in the compulsive switching condition, activity areas of the brain more concentrated in the left hemisphere; While under the condition of free conversion has no hemisphere differences, that is to say, under the condition of free switching, it need a pair of brain work together.(4) Different strategies during the repetition use different processing mechanism, and the repetition processing mechanism were also different in different experimental conditions. Whether in the compulsive switching condition or in the free switching condition, the main different time windows are both 0 – 200 ms. Strategy repetition time window in 0 – 200 ms showed individuals try to make the strategy transformation before the next trail do not tally with the actual requirements of strategy repetition, so it was the process from ready to transform state to repeat the same strategy.(5) Under the condition of free strategy switching, participants can take the initiative to transition to the optimal strategy, reflectng the individual has higher subjective initiative in the strategy transformation.