Characterizing Serial Order Processing in Working Memory and in the Language Domain

Abstract

The present project aimed to characterize the role of serial order within the working memory and language domains by first addressing a) whether serial order processing is domain-general and then b) whether serial order processing underlies vocabulary acquisition. Experiment 1 revealed that order memory in the visuo-spatial domain is qualitatively similar to order memory for verbal memoranda by reporting visuo-spatial equivalents of two well-known effects in verbal STM for serial order, repetition inhibition (e.g., Crowder, 1968) and repetition facilitation (Crowder, 1968). The effects were, however, accompanied by critical differences that may be due to modality-specific processes. Experiment 2 directly investigated whether verbal and visuo-spatial STM rely on common ordering mechanisms using a delayed recall dual-task design that contrasted two types of visuo-spatial interference tasks during a concurrent verbal serial order memory task (digit sequence memory). The visuo-spatial tasks probed either serial order STM or non-serial order (item) STM. Serial-order specific interference effects with the concurrent verbal serial order STM task were found. In experiment 3, we replicated the investigations of Experiment 2 using a word-learning paradigm as a concurrent task in place of the verbal serial order STM task that was previously used. Again interference by a visuo-spatial STM task was found only when it required memory for serial order. In sum, the results suggest that verbal and visuo-spatial STM subsystems rely on common mechanisms for serial order processing. These in turn appear to communicate with domain-specific processing substrates involved in item-level memory representations. Furthermore, the results indicate that such domain-general serial ordering mechanisms are also involved in novel word-learning. Taken together, the present findings provide crucial constraints for modeling of order representations. They also offer insight into mechanisms shared by vocabulary acquisition and STM tasks.