Phonological similarity effects in simple and complex span tasks

Three experiments were conducted to examine the effect of phonological similarity in simple and complex memory span tasks. In Experiment 1, participants performed either a simple or a complex span task, and the memoranda within lists were either phonologically similar or distinct. Phonologically similar lists consisted of words that rhymed.The simple span task was word span. There were two complex span tasks; one was the original reading span task, and the other was a variant of reading span in which all the sentences within a list were contextually related. The classic phonological similarity decrement was observed in word span. In contrast, phonological similarity facilitation was observed in both versions of reading span. This facilitation effect was further investigated in Experiment 2 using two new versions of reading span. In Experiment 2, the sentences in reading span were either short or long, and the memoranda were presented separately from, and were unrelated to, the sentences. Again, words within phonologically similar lists rhymed, and again, facilitation was observed. In Experiment 3, phonological similarity was operationalized in terms of feature overlap, rather than rhyme. The classic phonological similarity decrement was still observed in word span, but facilitation was not observed in complex span. The results suggest that phonological similarity, when operationalized using words that rhyme, serves as a list retrieval cue and that complex span tasks are more dependent on cue-driven memory retrieval mechanisms than are simple span tasks.     

Phonological similarity effects on detecting change in simple arrays

In two experiments, we investigated the effects on change detection and identification of the phonological similarity of the names of drawn objects shown in simple arrays. Experiment 1 examined the effects of phonological similarity on report of identity changes (in which one object was replaced by another) in a five-item array and Experiment 2 its effects on reporting switch changes (in which objects exchanged places). Phonological similarity did not impair change detection, and identification of new objects on change trials was more accurate in Experiment 1. H owever, phonological similarity significantly reduced change detection and identification of objects that switched location in Experiment 2. The results indicate different roles for a visual short-term memory system such as the visuospatial sketchpad and for phonological coding and storage in detecting and identifying replaced objects and object locations in arrays.     

Phonological similarity and lexicality effects in children's verbal short-term memory: concerns about the interpretation of probed recall data

Probed recall tasks are often used to assess aspects of children's verbal short-term memory development because they are not subject to potentially confounding output effects. However, the marked recency effects that are observed in probed recall means that these tasks are potentially insensitive to experimental manipulations when later serial positions are probed. This clouds the interpretation of data from probed recall studies in which children of different ages are presented with to-be-remembered lists of different lengths. In two experiments we examined the magnitude of phonological similarity and lexicality effects in both 5- to 6- and 8- to 9-year-old children. In each case performance on probed recall tasks was contrasted with that seen on tests of serial recognition. The results indicated that probed recall tasks are potentially less sensitive to experimental manipulations in younger than older children. However, comparable effects of both phonological similarity and lexicality were seen in both age groups using serial recognition procedures. These findings have implications for the interpretation of other studies that have examined the development of verbal short-term memory using probed recall and for theoretical accounts of the development of phonological similarity and lexicality effects in children.     

Phonological similarity and lexicality effects in children's verbal short-term memory: Concerns about the interpretation of probed recall data

Probed recall tasks are often used to assess aspects of children's verbal short-term memory development because they are not subject to potentially confounding output effects. However, the marked recency effects that are observed in probed recall means that these tasks are potentially insensitive to experimental manipulations when later serial positions are probed. This clouds the interpretation of data from probed recall studies in which children of different ages are presented with to-be-remembered lists of different lengths. In two experiments we examined the magnitude of phonological similarity and lexicality effects in both 5- to 6- and 8- to 9-year-old children. In each case performance on probed recall tasks was contrasted with that seen on tests of serial recognition. The results indicated that probed recall tasks are potentially less sensitive to experimental manipulations in younger than older children. However, comparable effects of both phonological similarity and lexicality were seen in both age groups using serial recognition procedures. These findings have implications for the interpretation of other studies that have examined the development of verbal short-term memory using probed recall and for theoretical accounts of the development of phonological similarity and lexicality effects in children.     

Visual similarity effects in immediate verbal serial recall

The role of visual working memory in temporary serial retention of verbal information was examined in four experiments on immediate serial recall of words that varied in visual similarity and letters that varied in the visual consistency between upper and lower case. Experiments 1 and 2 involved words that were either visually similar (e.g. fly, cry, dry; hew, new, few ) or were visually distinct (e.g. guy, sigh, lie; who, blue, ewe ). Experiments 3 and 4 involved serial recall of both letter and case from sequences of letters chosen such that the upper- and lower-case versions were visually similar, for example Kk, Cc, Zz, Ww , or were visually dissimilar, for example Dd, Hh, Rr, Qq . Hence in the latter set, case informationwas encoded interms of both the shape and the size of the letters. With both words and letters, the visually similar items resulted in poorer recall both with and without concurrent articulatory suppression. This visual similarity effect was robust and was replicated across the four experiments. The effect was not restricted to any particular serial position and was particularly salient in the recall of letter case. These data suggest the presence of a visual code for retention of visually presented verbal sequences in addition to a phonological code, and they are consistent with the use of a visual temporary memory, or visual "cache", in verbal serial recall tasks.     

Phonological similarity in working memory

That phonologically similar words in a short-term memory test are more difficult to recall than phonologically dissimilar words is a well-known phenomenon. This effect is the phonological similarity decrement. In the present study, we examined whether this phonological similarity decrement is present when additional semantic information is available, as in a reading span test, as compared with a standard presentation, or in the context of an operation span test. The results revealed a phonological similarity facilitation. Phonologically similar words were remembered better than phonologically dissimilar words.     

Phonological similarity and the irrelevant speech effect: implications for models of short-term verbal memory

Three experiments studied the interaction between irrelevant speech and phonological similarity within both the remembered and the irrelevant auditory material. Phonological similarity within the remembered list impaired performance in both baseline and irrelevant speech conditions, whereas phonological similarity between the remembered and ignored irrelevant items did not influence performance. Although there was a tendency for similarity within the irrelevant items to reduce interference, this proved to be a less robust finding. Implications for the theoretical interpretation of the irrelevant speech effect are discussed.     

Phonological similarity and the irrelevant speech effect: Implications for models of short-term verbal memory

Three experiments studied the interaction between irrelevant speech and phonological similarity within both the remembered and the irrelevant auditory material. Phonological similarity within the remembered list impaired performance in both baseline and irrelevant speech conditions, whereas phonological similarity between the remembered and ignored irrelevant items did not influence performance. Although there was a tendency for similarity within the irrelevant items to reduce interference, this proved to be a less robust finding. Implications for the theoretical interpretation of the irrelevant speech effect are discussed.     

Stimulus similarity decrements in children's working memory span

Two experiments investigated the impact of the relationship between processing and storage stimuli on the working memory span task performance of children aged 7 and 9 years of age. In Experiment 1, two types of span task were administered (sentence span and operation span), and participants were required to recall either the products of the processing task (sentence-final word, arithmetic total) or a word or digit unrelated to the processing task. Experiment 2 contrasted sentence span and operation span combined with storage of either words or digits, in tasks in which the item to be remembered was not a direct product of the processing task in either condition. In both experiments, memory span was significantly greater when the items to be recalled belonged to a different stimulus category from the material that was processed, so that in sentence span tasks, number recall was superior to word recall, and in operation span tasks, word recall was superior to number recall. Explanations of these findings in terms of similarity-based interference and response competition in working memory are discussed.     

Individual differences in phonological learning and verbal STM span

A relationship between phonological short-term memory tasks (e.g., nonword repetition, digit span) and vocabulary learning in both experimental and real-life conditions has been reported in numerous studies. A mechanism that would explain this correlation is, however, not known. The present study explores the possibility that it is the quality of phonological representations that affects both short-term recall and long-term learning of novel wordlike items. In Experiment 1, groups with relatively good and poor span for pseudowords were established. The good group was found to perform better at explicit memory tasks tapping the incidental learning of a limited stimulus pool used in an auditory immediate serial pseudoword recall task. In Experiment 2, the results of Experiment 1 were replicated when experience of correct recall was controlled. In Experiment 3, the immediate recall performance of the good group was found to benefit more than that of the poor group from syllable repetition within stimulus pools. It is concluded that the efficiency of a process that creates phonological representations is related both to short-term capacity for verbal items, and to long-term phonological learning of the structure of novel phonological items.     

Interference between maintenance and processing in working memory: the effect of item-distractor similarity in complex span

Four experiments examined the effect of phonological similarity between items and distractors on complex span performance. Item-distractor similarity benefited serial recall when distractors followed the items they were similar to, but not when distractors preceded the items they were similar to. These findings are predicted by C-SOB (contextual serial order in a box), a computational model of complex span. The model assumes that distractors are involuntarily encoded into memory, being associated to the preceding item's list position. Distractors interfere with items by superposition of distributed representations that are associated to the same position. Superposition distorts item memory; this distortion is less severe when the distractor is similar to the item. Further support for the assumption that distractors are encoded at the position of the preceding item comes from the finding that intrusions of distractors at recall tended to come from the position of the target item. In addition, intruding distractors tend to replace items to which they are similar, showing that lack of distinctiveness also contributes to interference.     

Phonological similarity and enhanced auditory recency in longer-term free recall

The effect of phonological similarity amongst list items on the modality effect was investigated in free recall with distraction activity interpolated before and after each list word. In Experiment 1 the distractor activity involved counting backward silently mouthing each number, and the modality effect was drastically attenuated by high similarity. This outcome is comparable with that found in immediate recall, and it is consistent with an echoic memory interpretation. In Experiment 2 the same backward-counting task was performed with each number being vocalized, and the modality effect was unaffected by phonological similarity. This outcome leads to the stronger conclusion that, under those conditions at least, the modality effect cannot be echoic. Implications of these findings for general theoretical accounts of the modality effect are discussed.     

Examining the locus of age effects on complex span tasks

To investigate the locus of age effects on complex span tasks, the authors evaluated the contributions of working memory functions and processing speed. Age differences were found in measures of storage capacity, language processing speed, and lower level speed. Statistically controlling for each of these in hierarchical regressions substantially reduced, but did not eliminate, the complex span age effect. Accounting for lower level speed and storage, however, removed essentially the entire age effect, suggesting that both functions play important and independent roles. Additional evidence for the role of storage capacity was the absence of complex span age differences with span size calibrated to individual word span performance. Explanations for age differences based on inhibition and concurrent task performamce were not supported.     

Dissociative style and individual differences in verbal working memory span

Dissociative style is mostly studied as a risk factor for dissociative pathology, but it may also reflect a fundamental characteristic of healthy information processing. Due to the close link between attention and working memory and the previous finding of enhanced attentional abilities with a high dissociative style, a positive relationship was also expected between dissociative style and verbal working memory span. In a sample of 119 psychology students, it was found that the verbal span of the high-dissociative group was about half a word larger than of the medium and low-dissociative groups. It is suggested that dissociative style may be one of only very few individual differences that is directly relevant to consciousness research.     

Phonological awareness and the use of phonological similarity in letter-sound learning

The effects of the phonological similarity between a letter sound and the sound in a spoken word, and phonological awareness on letter-sound learning were examined. Two groups of 41 kindergartners were taught four letter sounds. First, both groups had to learn the associations between four symbols and four familiar words. Next, both groups were taught the letter sounds that were paired to these same symbols. Each letter sound corresponded to the first sound of the word that was previously associated with that symbol in the phonological similarity group, whereas such a relation was absent in the other group. In addition, measures of vocabulary, letter knowledge, and phonological awareness were administered. Phonological similarity facilitated letter-sound learning. Individual differences in phonological awareness had a strong effect on letter-sound learning even after current letter knowledge was controlled. Unexpectedly, the effects of phonological awareness and the ability to use phonological similarity on letter-sound learning were found to be independent.     

The role of verbal ability in the processing of complex verbal information

Summary This study investigated the relation between psychometric mental-ability test scores and several reaction-time measures; a simple-reaction task, a choice-reaction task, the Posner and Mitchell (1967) letter-identification task, and a variation of the sentence-verification task. Scores on the Raven Advanced Progressive Matrices and the Verbal Subtest of the Scholastic Aptitude Test (SATV) were obtained. The less complex information-processing tasks replicate earlier studies in which general intelligence was only marginally related to reaction-time measures. The sentence-verification task systematically varied task complexity. Several direct and derived measures from the task were significantly correlated with psychometric mentalability measures. However, even though a number of precautions were taken to ensure that the sentence-verification task assessed purely verbal-processing efficiency, there was little evidence for an important task-specific relation between verification measures and verbal ability. Moreover, despite its relative verbal complexity, sentence verification did not reflect a greater relationship to verbal ability than other tasks did. Overall, the information-processing efficiency measures used in this study suggested a fairly general, rather than a task-specific, relationship to intellectual ability.The research presented in this paper was conducted while the first author was affiliated with the University of Georgia, U. S. A.     

Phonological priming and cohort effects in toddlers

Adult word recognition is influenced by prior exposure to phonologically or semantically related words (cup primes cat or plate) compared to unrelated words (door), suggesting that words are organised in the adult lexicon based on their phonological and semantic properties and that word recognition implicates not just the heard word, but also related words. We investigate the phonological organisation of the toddler lexicon with two experiments using a picture priming technique. Twenty-four month olds showed inhibition of target recognition in related primed trials compared to unrelated primed trials (Experiment 1) and also in related primed trials compared to unprimed trials (Experiment 2). Further analysis of children’s responding found that this inhibition effect was modulated by the cohort and neighbourhood size of the words tested. Overall, the results indicate a lexical basis for the reported effects and suggest that the phonological properties provide an organisational basis for words in the toddler lexicon.