Effects of phonetic duration and phonological complexity on immediate recall and articulation rate of English and Chinese words

In testing the hypothesis that the word-length effect can be abolished when the phonological complexity of memory items is controlled, two sets of English and Chinese words were constructed respectively for an English and a Chinese memory span task. The cross-linguistic approach was taken because a natural confound between phonological complexity and spoken duration of the English words would greatly limit the ability to test the hypothesis if English were the only source of information.; To validly test this hypothesis, items were tightly controlled for phonological complexity in terms of number of phonemic and subphonemic units. The phonetic durations between the sets were reliably different as measured in a speeded-repetition condition similar to the rehearsal process. No differences were found in memory spans for the long vs. short sets in both language groups, suggesting that the word-length effect is abolished when the phonological complexity of items is controlled.; To further differentiate the factors of complexity and duration on the word-length effect, a second hypothesis tested whether phonological complexity alone would affect memory span when duration is held constant. Recall was significantly better for words with fewer segments than for words with more segments in both language groups. These results strongly suggest that segmental complexity rather than item duration determines the word-length effect.; To evaluate whether articulatory duration was confounded with phonological complexity, durations were measured in both speeded- and nonspeeded-speaking conditions. It was found that English speakers articulated the more-segment items more slowly than the fewer-segment items only in the speeded condition. However, Chinese speakers articulated the more-segment and fewer-segment items at similar rates in both conditions.; Despite the confound with the English stimuli in testing the effect of segmental complexity on memory span, the hypothesis is still supported by results of the Chinese study, where complexity was not confounded with duration. Ramifications for how to control for durational differences with English stimuli are discussed. Overall, the results help clarify the debate in the literature regarding sources of the word-length effect, providing further details for more precise modeling of phonological working memory.