Phonetic variability across talkers imposes additional processing costs during speech perception, often measured by performance decrements between single- and mixed-talker conditions. However, models differ in their predictions about whether accommodating greater phonetic variability (i.e., more talkers) imposes greater processing costs. We measured speech processing efficiency in a speeded word identification task, in which we manipulated the number of talkers (1, 2, 4, 8, or 16) listeners heard. Word identification was less efficient in every mixed-talker condition compared to the single-talker condition, but the magnitude of this performance decrement was not affected by the number of talkers. Furthermore, in a condition with uniform transition probabilities between two talkers, word identification was more efficient when the talker was the same as the prior trial compared to trials when the talker switched. These results support an auditory streaming model of talker adaptation, where processing costs associated with changing talkers result from attentional reorientation.

说话者之间的语音可变性在语音感知过程中增加了额外的处理成本，通常通过单个和混合说话者条件之间的性能下降来衡量。然而，模型对适应更大的语音可变性（即更多的说话者）是否会带来更大的处理成本的预测有所不同。我们在快速单词识别任务中测量了语音处理效率，在该任务中，我们操纵了听到的说话者（1、2、4、8 或 16）个听众的数量。与单一说话者条件相比，每个混合说话者条件下的单词识别效率较低，但这种性能下降的幅度不受说话者数量的影响。此外，在两个说话者之间具有统一转移概率的条件下，与说话者切换时的试验相比，当说话者与先前的试验相同时，单词识别更有效。这些结果支持谈话者适应的听觉流模型，其中与改变谈话者相关的处理成本来自注意力重新定向。