The effect of concurrent semantic categorization on delayed serial recall

The role of working memory loads on immediate and long-term sentence recall

It is well-established that both phonological and semantic knowledge influence verbal working memory. However, the focus has primarily been on understanding phonological effects despite evidence of semantic influences. Articulatory suppression is a well-established task for preventing phonological processing. Methods to prevent semantic processing have rarely been used in the past, highlighting a need for developing a semantic interference task. We, therefore, conceptualised two novel tasks - an animacy categorisation and semantic relatedness judgement task. This study explored the impact of phonological (articulatory suppression) and semantic loads (animacy categorisation and semantic relatedness judgement) on immediate and delayed sentence recall. Additionally, sentence concreteness (concrete vs. abstract sentences) indexed semantic knowledge in verbal working memory. Across two studies, immediate recall revealed that articulatory suppression (preventing phonological processing) increased the size of the concreteness effect, while the novel semantic tasks (preventing semantic processing) reduced it suggesting that our semantic tasks were indeed imposing a semantic load. Further, relative long-term performance showed that more new words were remembered in articulatory suppression, whereas recall was disproportionately impaired in the semantic relatedness task. Our experimental paradigm offers phonological and semantic suppression tasks that can be used in parallel to investigate the interactions between working memory and language.

The role of phonological and semantic representations in verbal short-term memory and delayed retention

It has been suggested that phonological representations play a central role in verbal short-term memory, but when semantic knowledge has been investigated, it has also been shown to influence verbal short-term memory. Explaining this interaction between verbal short-term memory and the linguistic system has produced different theoretical positions: whether semantic knowledge is used to redintegrate phonological traces or if there is direct activation of both phonological and semantic knowledge upon encountering a word. The present study employed a new paradigm to systematically examine phonological and semantic representations in verbal short-term memory as well as long-term impacts. Across two experiments, a list of words was presented sequentially, followed by a probe word. Participants were to judge whether the probe word rhymed or was synonymous with any items on the list. Delayed memory was also tested. In Experiment 1, we found that immediate performance was better for synonym than rhyme judgements, and this continued to be the case after a brief delay. In Experiment 2, under a fast-encoding, running-span paradigm, we found similar activation of phonological and semantic knowledge. Nevertheless, accuracy was again higher for items probed with the semantic than rhyme cue in the long term. Results showed that indeed there are short-term semantic effects, in addition to phonological effects. Further, semantic processing can occur in a highly automatic and rapid manner, with strong influence on long-term memory. These findings provide a new perspective on viewing verbal short-term memory as operating more dynamically within the context of a complex linguistic system.

Can activated long-term memory maintain serial order information?

The maintenance of serial order information is a core component of working memory (WM). Many theoretical models assume the existence of specific serial order mechanisms. Those are considered to be independent from the linguistic system supporting maintenance of item information. This is based on studies showing that psycholinguistic factors strongly affect the ability to maintain item information, while leaving order recall relatively unaffected. Recent language-based accounts suggest, however, that the linguistic system could provide mechanisms that are sufficient for serial order maintenance. A strong version of these accounts postulates serial order maintenance as emerging from the pattern of activation occurring in the linguistic system. In the present study, we tested this assumption via a computational modeling approach by implementing a purely activation-based architecture. We tested this architecture against several experiments involving the manipulation of semantic relatedness, a psycholinguistic variable that has been shown to interact with serial order processing in a complex manner. We show that this activation-based architecture struggles to account for interactions between semantic knowledge and serial order processing. This study fails to support activated long-term memory as an exclusive mechanism supporting serial order maintenance.

Word imageability and orthographic neighbourhood effects on memory: a study in free recall and recognition

This study investigated the effects of word imageability and orthographic neighbourhood size, as well as their combined effects, in free recall and recognition memory. A total of 45 young adults performed recall and recognition tasks on the same word materials. Word imageability and orthographic neighbourhood size were orthogonally manipulated across four word conditions: low-imageability words - high N, saveur [flavor], low-imageability words - low N, total [total], high-imageability words - high N, carré [square] and high-imageability - low N, nuage [cloud]. The results show that word imageability facilitates memory performance in both free recall and recognition tasks, while the effect of orthographic neighbourhood size was exhibited only in the recognition task. Finally, the orthographic neighbourhood effect was found to depend on word imageability. The implications of the results are discussed according to semantic and orthographic word characteristics with regard to the memory processes involved in free recall and recognition tasks.

Verbal Working Memory as Emergent from Language Comprehension and Production

This article reviews current models of verbal working memory and considers the role of language comprehension and long-term memory in the ability to maintain and order verbal information for short periods of time. While all models of verbal working memory posit some interaction with long-term memory, few have considered the character of these long-term representations or how they might affect performance on verbal working memory tasks. Similarly, few models have considered how comprehension processes and production processes might affect performance in verbal working memory tasks. Modern theories of comprehension emphasize that people learn a vast web of correlated information about the language and the world and must activate that information from long-term memory to cope with the demands of language input. To date, there has been little consideration in theories of verbal working memory for how this rich input from comprehension would affect the nature of temporary memory. There has also been relatively little attention to the degree to which language production processes naturally manage serial order of verbal information. The authors argue for an emergent model of verbal working memory supported by a rich, distributed long-term memory for language. On this view, comprehension processes provide encoding in verbal working memory tasks, and production processes maintenance, serial ordering, and recall. Moreover, the computational capacity to maintain and order information varies with language experience. Implications for theories of working memory, comprehension, and production are considered.

An item-level analysis of lexical-semantic effects in free recall and recognition memory using the megastudy approach

Psycholinguists have developed a number of measures to tap different aspects of a word's semantic representation. The influence of these measures on lexical processing has collectively been described as semantic richness effects. However, the effects of these word properties on memory are currently not well understood. This study examines the relative contributions of lexical and semantic variables in free recall and recognition memory at the item-level, using a megastudy approach. Hierarchical regression of recall and recognition performance on a number of lexical-semantic variables showed task-general effects where the structural component, frequency, number of senses, and arousal accounted for unique variance in both free recall and recognition memory. Task-specific effects included number of features, imageability, and body-object interaction, which accounted for unique variance in recall, whereas age of acquisition, familiarity, and extremity of valence accounted for unique variance in recognition. Forward selection regression analyses generally converged on these findings. Hierarchical regression also revealed that lexical variables accounted for more variance in recognition compared with recall, whereas semantic variables accounted for more unique variance above and beyond lexical variables in recall compared with recognition. Implications of the findings are discussed.

Short-term memory and long-term memory are still different

A commonly expressed view is that short-term memory (STM) is nothing more than activated long-term memory. If true, this would overturn a central tenet of cognitive psychology-the idea that there are functionally and neurobiologically distinct short- and long-term stores. Here I present an updated case for a separation between short- and long-term stores, focusing on the computational demands placed on any STM system. STM must support memory for previously unencountered information, the storage of multiple tokens of the same type, and variable binding. None of these can be achieved simply by activating long-term memory. For example, even a simple sequence of digits such as "1, 3, 1" where there are 2 tokens of the digit "1" cannot be stored in the correct order simply by activating the representations of the digits "1" and "3" in LTM. I also review recent neuroimaging data that has been presented as evidence that STM is activated LTM and show that these data are exactly what one would expect to see based on a conventional 2-store view. (PsycINFO Database Record