| 摘要: | 近年來的研究已經證實作業轉換能力的訓練和轉移效果，但是對這個相當重要的執行功能而言，作業轉換歷程的哪個成分可以被訓練和轉移仍待探討。本研究目的在探討：1) 作業轉換歷程的不同階段在作業轉換訓練後之訓練和轉移效果；2)不同年齡組群訓練是否產生不同訓練效果。 我們使用了加減轉換的作業做為訓練作業，並使用隨機轉換的序列讓受試者無需主動去監控當下的作業，而是看到提示出現再作決定。訓練時程的前測、訓練階段和後測都包含了一個標準作業，用來衡量作業轉換能力的改變，另外，訓練前後測階段都包含一些轉移作業，包含相同或不同的認知能力作業，以評估訓練效果轉移到其他作業時，這些轉移作業與訓練作業相似程度的影響。 實驗1A和1B中，四個單一向度的加減轉換作業被用來訓練受試者的作業轉換能力，經過了三週共十次的訓練後，雖然年青組或老年組的加減運算表現都進步，但是兩組受試者都沒有出現在轉換代價上訓練或轉移的效果。不過，老年人的訓練效果似乎有比年輕人大的傾向。在實驗2A和2B中，我們以類似的加減轉換作業，在兩週的期間訓練受試者達四次，同時增加了每次訓練的長度，並且在轉移作業上設計不同的作業難度來衡量訓練後的轉移效果。然而我們仍舊沒有觀察到訓練和轉移的效果。我們認為在實驗1和實驗2中所使用的單一向度作業，相較於其它發現了訓練和轉移效果的(雙向度)作業轉換作業，缺乏了「干擾控制」成分。為了進一步求證干擾控制在作業轉換能力訓練和轉移效果中的重要性，實驗3使用了雙向度的作業轉換作業來訓練年輕受試者。結果觀察到顯著的訓練和轉移效果，然而我們並沒有觀察到在唸色作業上的轉移效果，這可能顯示干擾控制能力訓練效果的特定性。 總結來說，本研究顯示作業轉換能力在雙向度的情境下才能產生有效的訓練和轉移效果。意即，作業轉換歷程中所包含的干擾抑制成分對訓練效果有其重要性。其次，對訓練後的轉移效果而言，干擾抑制成分的加入並不足以產生不同認知領域(唸色作業)的轉移效果，其它工作記憶成分可能也佔有重要角色。 Although recent research has demonstrated training and transfer effects for task-switching, it remains to be clarified which component(s) for this important ability of executive functions was influenced by training. The current study aimed at exploring the componential process(es) that contributes to training and transfer effects in task-switching. Following the same vein, age differences were also compared. We adopted the plus-and-minus paradigm as the training task, and implemented random switching sequence in order to study the training and transfer effects while participants did not have to actively keep track of the task to be performed. A criterion task was performed throughout pre-training, training, and post-training sessions to evaluate training effect, while a few different transfer tasks which were only performed at pre- and post-training sessions to assess near and far-transfer of training. In Experiment 1A and 1B, participants were trained on four revised versions of univalent plus-minus switching task for ten sessions within a period of three weeks. Neither training nor transfer effect was found in both age groups. However, there was a trend of larger training effect in mixing cost for the older than the young group. In Experiment 2A and 2B, participants were trained with the same plus-minus switching tasks for six training sessions within two weeks. The Cue-Target Interval (CTI) and task difficulty of the training task was set between the levels adopted in the near-transfer task. Yet again there was no training or transfer effect associated with age, CTI, or difficulty. We speculated that the training of univalent switching, as adopted in both Experiment 1 and 2, lacked the interference-control process in bivalent switching tasks adopted in other studies which found transfer effect. We assessed the role of interference-control process in Experiment 3 with only young adults by using bivalent stimulus to require a higher extent of interference control for task-switching. The results showed significant training and transfer effect in the mixing cost. However, there was no far-transfer effect in the Stroop task, suggesting domain-specificity in the interference-control process. Taken all results together, the current study showed that the training and near-transfer could be more reliably induced by training in the bivalent than in the univalent task-switching paradigm, and that the merely adding interference control may not sufficient to induce the far transfer effect in Stroop-type tasks, other working memory load may also contribute to far-transfer effects after task-switching training. |
