Mecklinger A, Ullsperger P
Institute for Psychology, Free University, Berlin, Germany.
Electroencephalogr Clin Neurophysiol. 1993 Jun;86(6):395-407. doi: 10.1016/0013-4694(93)90135-i.
We examined the relationship between P3 amplitude elicited by different auditory task stimuli and response-defined categorization requirements. Two experiments were conducted which examined the effects of the categorization of tone pitches (experiment 1) and spoken digits (experiment 2) on P3 amplitude. The categorization requirements were the same in both experiments. Two patterns of results were found in experiment 1: first, when subjects had to categorize an end term within the stimulus scale the largest P3 amplitudes were elicited by this stimulus. Secondly, when all tone pitches had to be categorized separately or when the categorization of the middle tone pitch was required, P3 amplitudes were smallest for the middle tone pitch and increased in amplitude at both ends of the stimulus scale. Different patterns of results were found in experiment 2. When subjects had to categorize 1 out of 5 spoken digits the largest P3 amplitudes were elicited by this digit no matter which position it had on the stimulus scale. In addition, only negligible P3s were found in the condition in which each of the digits had to be categorized separately. It is argued (i) that spoken words yield a higher degree of distinctiveness than tone pitches and (ii) that P3 amplitude is related to the probability of response-defined task categories only to the extent that stimuli can easily be assigned to categories.
我们研究了不同听觉任务刺激所诱发的P3波幅与基于反应定义的分类要求之间的关系。进行了两项实验，分别考察了音调分类（实验1）和语音数字分类（实验2）对P3波幅的影响。两项实验中的分类要求相同。实验1发现了两种结果模式：第一，当受试者必须对刺激范围内的一个端点项进行分类时，该刺激诱发的P3波幅最大。第二，当所有音调都必须单独分类或需要对中间音调进行分类时，中间音调的P3波幅最小，且在刺激范围的两端波幅增大。实验2发现了不同的结果模式。当受试者必须对5个语音数字中的1个进行分类时，无论该数字在刺激范围内处于什么位置，它诱发的P3波幅最大。此外，在每个数字都必须单独分类的条件下，仅发现了可忽略不计的P3波。有人认为：（i）语音比音调具有更高的辨识度；（ii）P3波幅仅在刺激能够轻易地被归类到任务类别中的程度上与基于反应定义的任务类别的概率相关。
