Morton J, Marcus S M, Ottley P
J Exp Psychol Gen. 1981 Dec;110(4):568-93. doi: 10.1037//0096-3445.110.4.568.
The stimulus suffix paradigm has been used to establish the importance of precategorical acoustic storage (PAS) as a theoretical construct in the investigation of attention and speech perception. Morton and Chambers concluded that sounds must have typical "speechlike" properties extracted at an early stage of processing in order to act as suffixes. In this article we use the suffix effect to investigate the conditions under which a sound is treated by the acoustic system as speechlike. On the basis of our findings we then perform other studies that reaffirm the essentially precategorical nature of the memory source termed PAS by Crowder and Morton. In Experiments 1-13 we demonstrate the complex basis on which sounds are classified. Our experiments show that a completely regular sound, in which a single pitch pulse from a naturally spoken vowel was repeatedly reproduced, still produced a substantial suffix effect. In addition a natural sound had to be quite severely filtered before the suffix effect began to vanish. However, a combination of regularity and filtering proved very effective, the two dimensions dramatically interacting in neutralizing the effect of the sound as a suffix. In two further experiments (14 and 15) we show that the classification parameters can be shifted by changing the acoustic properties of the stimulus list. However, forcing the subjects to make a linguistic classification of suffix sounds did not lead to any changes in their potency as suffixes. The classification of sounds, and thus the suffix effect, is an acoustic question, not a subjective one. The distinction between subjective and acoustic influences was further demonstrated when subjects rated a variety of sounds for their naturalness and for their similarity to the original suffix (Experiments 17-22). These measures showed themselves sensitive to the filtering operations we performed but, unlike measures of suffix effectiveness, were insensitive to regularity. Another suffix that produced a full suffix effect was shown to be rated as very nonspeechlike. Contrary to recent claims, these results reinforce our view of a distinction between central, subjectively controllable factors and a strong precategorical effect that is automatic in action and is based on the decision of whether a sound is speechlike.
刺激后缀范式已被用于确立前分类声学存储（PAS）作为一种理论结构在注意力和言语感知研究中的重要性。莫顿和钱伯斯得出结论，声音必须在处理的早期阶段提取出典型的“类语音”属性，才能作为后缀起作用。在本文中，我们利用后缀效应来研究声音在何种条件下被声学系统视为类语音。基于我们的研究结果，我们随后进行了其他研究，这些研究再次证实了克劳德和莫顿所称的PAS记忆源本质上的前分类性质。在实验1 - 13中，我们展示了声音分类的复杂基础。我们的实验表明，一个完全规则的声音，即自然说出的元音中的单个音高脉冲被反复重现，仍然会产生显著的后缀效应。此外，在后缀效应开始消失之前，自然声音必须经过相当严格的滤波。然而，规则性和滤波的结合被证明非常有效，这两个维度在抵消声音作为后缀的效果方面显著相互作用。在另外两个实验（14和15）中，我们表明通过改变刺激列表的声学属性可以改变分类参数。然而，强迫受试者对后缀声音进行语言分类并不会导致它们作为后缀的效力发生任何变化。声音的分类，以及后缀效应，是一个声学问题，而不是一个主观问题。当受试者对各种声音的自然度以及与原始后缀的相似度进行评分时（实验17 - 22），主观影响和声学影响之间的区别得到了进一步证明。这些测量结果显示它们对我们进行的滤波操作敏感，但与后缀有效性的测量不同，对规则性不敏感。另一个产生完全后缀效应的后缀被证明被评为非常不像语音。与最近的说法相反，这些结果强化了我们的观点，即中央的、主观可控的因素与强大的前分类效应之间存在区别，前分类效应是自动起作用的，并且基于声音是否为类语音的判断。
