Bottleneck Influences on the Processing Stages of Word Production

Word production proceeds through the processing stages of lemma selection, phonological word-form selection, and phoneme selection. We assessed whether each of these processing stages is subject to a central processing bottleneck, causing it to delay a concurrently performed task. Subjects named line-drawn pictures as they performed a three-tone auditory discrimination task. In Experiment 1, subjects named pictures that completed cloze sentences; lemma selection was manipulated with highand low-constraint cloze sentences, and phonological word-form selection with pictures that had highand low-frequency names. In Experiment 2, subjects named pictures while ignoring visually presented distractor words; lemma selection was manipulated with conceptually related distractors and phoneme selection with phonologically related distractors. All manipulations except the phoneme-selection manipulation delayed tone-discrimination responses as much as picture-naming responses. The results suggest that the early stages of word production – lemma and phonological word-form selection – are subject to a central processing bottleneck, while the later stage – phoneme selection – is not.