Abstract: 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 circum stance 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 anage effect.The cognitive mechanisms of processing stimuli for childrenand adults may be different;(3) P400 which appeared in the condition of sequential category induction task might be the symbol of category inductionand unrelated with the concrete processing of the attributes of stimuli.

Key words: category introduction, event-related potentials(ERPs), p sychological development