继时呈现条件下类别归纳过程的ERPs研究

ERP Study of Category Induction by Sequentially Presenting Stimuli

采用ERP技术对继时呈现条件下类别归纳过程进行了实验研究。使用几何图形为材料,18名被试在单维属性不告知、单维属性告知、双维属性不告知三种条件下完成类别归纳任务。通过对相关ERP成分的分析得出以下结论:(1)在继时呈现归纳材料的情况下,对刺激的加工是在已有背景基础上对后来呈现的刺激进行选择性加工,从而形成类别;(2)成年人与儿童在类别归纳中认知加工方式可能存在不同,当类别归纳的复杂程度增加时,即在需要归纳的属性从一个变为两个的时候,成年人仍然倾向于通过归纳出类别判断规则用于分类任务,而非通过相似性进行判断;(3)继时呈现材料条件下类别归纳任务中出现的P400可能是标志类别归纳过程完成的ERP成分,而且与对刺激属性加工具体过程无关。

The process of category induction sequentially presenting stimuli was studied with ERP technique. The stimuli were all geometry figures. Eighteen subjects performed three tasks including two uni-dimensional tasks, one of which gave the instruction before each trial and the other one did not, and one multi-dimensional task that the category standard was two dimensions. The ERP analysis supported that （ 1 ） under the circumstance of presenting the stimuli sequentially, the following stimulus was processed based on the context provided by the previous one, then led to the formation of a new category; （2） With the difficulties＇ and dimensions＇ increasing, adults still used rules as strageties for categorization, which was different from the children who preferred similarities. So we infer from the electrophysiology aspect that category induction has an age effect. The cognitive mechanisms of processing stimuli for children and adults may be different ; （3） P400 which appeared in the condition of sequential category induction task might be the symbol of category induction and unrelated with the concrete processing of the attributes of stimuli.