Hitch Graham J, Fastame Maria Chiara, Flude Brenda
Department of Psychology, University of York, York YO10 5DD, UK.
Memory. 2005 Apr-May;13(3-4):247-58. doi: 10.1080/09658210344000314.
Current models of verbal short-term memory (STM) propose various mechanisms for serial order. These include a gradient of activation over items, associations between items, and associations between items and their positions relative to the start or end of a sequence. We compared models using a variant of Hebb's procedure in which immediate serial recall of a sequence improves if the sequence is presented more than once. However, instead of repeating a complete sequence, we repeated different aspects of serial order information common to training lists and a subsequent test list. In Experiment 1, training lists repeated all the item-item pairings in the test list, with or without the position-item pairings in the test list. Substantial learning relative to a control condition was observed only when training lists repeated item-item pairs with position-item pairs, and position was defined relative to the start rather than end of a sequence. Experiment 2 attempted to analyse the basis of this learning effect further by repeating fragments of the test list during training, where fragments consisted of either isolated position-item pairings or clusters of both position-item and item-item pairings. Repetition of sequence fragments led to only weak learning effects. However, where learning was observed it was for specific position-item pairings. We conclude that positional cues play an important role in the coding of serial order in memory but that the information required to learn a sequence goes beyond position-item associations. We suggest that whereas STM for a novel sequence is based on positional cues, learning a sequence involves the development of some additional representation of the sequence as a whole.
当前的言语短期记忆（STM）模型提出了多种用于序列顺序的机制。这些机制包括项目上激活的梯度、项目之间的关联以及项目与其相对于序列开头或结尾位置之间的关联。我们使用一种变体的赫布程序对模型进行了比较，在该程序中，如果一个序列被呈现多次，那么该序列的即时序列回忆能力会得到提高。然而，我们不是重复完整的序列，而是重复训练列表和后续测试列表中序列顺序信息的不同方面。在实验1中，训练列表重复了测试列表中的所有项目-项目配对，无论是否包含测试列表中的位置-项目配对。只有当训练列表重复带有位置-项目配对的项目-项目配对，并且位置是相对于序列的开头而不是结尾来定义时，相对于控制条件才观察到显著的学习效果。实验2试图通过在训练期间重复测试列表的片段来进一步分析这种学习效果的基础，其中片段由孤立的位置-项目配对或位置-项目和项目-项目配对的簇组成。序列片段的重复仅导致微弱的学习效果。然而，在观察到学习效果的情况下，是针对特定的位置-项目配对。我们得出结论，位置线索在记忆中序列顺序的编码中起着重要作用，但学习一个序列所需的信息超出了位置-项目关联。我们认为，虽然对于一个新序列的STM基于位置线索，但学习一个序列涉及对整个序列的一些额外表征的发展。
