Abstract: Blocking is an interesting phenomenon in learning. When a cue can predict the outcome effectively, it will block learning of other cues. Some versions of the error-driven learning have been incorporated into most category learning models and suggested that features useful for categorizations would block learning of other features. According to error-driven views, no matter the category has a theme or not, features can be used to classify all exemplars perfectly would block learning of other features. In contrast, some researchers indicate that different from association learning, category learning is a high level cognitive processing and people would like to learn more features than classification. When there is a theme in category, the theme knowledge helps to strengthen the activation of features and more features are learned. Are there some cognitive mechanisms in category learning in addition to error-driven mechanism? In a blocking paradigm, the category learning mechanisms have been investigated in three experiments by testing the knowledge effect in category learning. In experiment 1, rote features were defined as defining features to investigate whether the theme knowledge affected category learning. No feature learning superiority has been found in the theme knowledge condition. One possibility was that the rote defining features made participants had difficulty in getting the theme knowledge. In experiment 2, defining features were changed to knowledge features and besides defining features some features had been learned. It indicated that the theme knowledge in the category helped to learn more features and blocking effect disappeared. Experiment 3 got the same results while the defining knowledge features had been fixed on the top of exemplar. When there was a theme in category, the disappearance of blocking effect in category learning indicated that category learning was not solely driven by error-reduction. The cognitive mechanism in category learning helped to make use of theme knowledge and learn more features. A primary conclusion can be made that there are both error-driven mechanism and cognitive mechanism in category learning.

Key words: category learning, blocking, theme knowledge, error-driven

摘要： 三个实验采用阻碍效应研究范式探讨主题知识对类别学习的影响。实验1探讨定义特征维度为机械特征时，主题知识对类别学习的影响；实验2和实验3，通过考察定义特征维度为知识特征时，类别学习中阻碍效应的大小，继续探讨主题知识对类别学习的影响。实验结果发现：（1）当定义特征维度为机械特征时，主题知识的存在没有促进类别学习。这可能因为定义特征维度为机械特征，主题知识难以发现所致；（2）当定义特征维度为知识特征时，类别学习中的阻碍效应消失，证明主题知识的存在促进了类别学习。研究结果再次支持了类别学习不仅仅受到减少归类错误驱动的观点。

关键词: 类别学习, 阻碍效应, 主题知识, 错误驱动