Depth of phonological recoding in short-term memory

In testing the hypothesis that surface phonetic form is included in short-term memory (STM) representation, the tone sandhi phenomenon in Mandarin Chinese was exploited, and, as a prerequisite, the hypothesis that tonal similarity affects STM of verbal material in a tone language was also tested. In Experiment 1, subjects recalled visually presented sequences of seven monosyllabic Chinese morphemes having either the same tone or different tones. More errors were made on the monotonal sequences than on the multitonal sequences, confirming the effect of tonal similarity on STM. In Experiment 2, subjects recalled visually presented sequences of disyllabic nonsense words. The sequences were designed in such a way that half of them were subject to the tone sandhi rule in Mandarin Chinese, whereas the other half were not. The consequence of applying the tone sandhi rule, as designed, was to make all the first characters in the sequences identical in pronunciation, thus creating potential phonological confusion. More errors, indeed, occurred on the sequences subject to the tone sandhi rule than on those not subject to it, indicating the existence of a surface phonetic representation in STM. The findings in this study provide further insight into the phonological mechanism of STM. Different accounts for this mechanism are also discussed in the light of the new findings.     

The effects of unvocalized music on short-term memory

The studies reported here investigated the role of background music in verbal processing. The experiment was a partial replication of Salame and Baddeley (1989), where the effect of music on the recall of digits, was examined, but included an additional key condition where participants heard instrumental music without the words usually associated with it. In this case we used nursery rhymes. In addition, articulatory suppression was manipulated as a tool to look at the role of working memory in the task. The relationship between long-term memory and working memory was further explored by using an implicit memory task to examine verbal memory effects for words associated with the music but not actually heard. The results indicated that background, instrumental music, long-associated with words, significantly impairs concurrent verbal processing. These long-term memory effects on working memory were, however, not associated with implicit memory effects, and no priming was observed.     

Genetic influences on language impairment and phonological short-term memory

It has been known for some years that specific language impairment (SLI), an unexpected failure to acquire age-appropriate language skills, is highly heritable. However, molecular genetic studies have been hampered by the heterogeneity of the disorder and the predominant lack of clear genotype-phenotype relationships. We review recent studies suggesting that a better understanding of the genetics of SLI might emerge if we move away from clinical criteria for diagnosis to look instead at a theoretically based quantitative and cognitive measure of the phenotype: a test of phonological short-term memory (STM). Deficient phonological STM has been linked to specific genetic loci, and might play a role in determining some types of reading impairment as well as SLI. Identifying those cognitive deficits that work best as indices of heritable phenotypes will help us to uncover the aetiology of developmental disorders.     

The phonological neighbourhood effect on short-term memory for order

There is a growing body of literature that suggests that long-term memory (LTM) and short-term memory (STM) structures that were once thought to be distinct are actually co-dependent, and that LTM can aid retrieval from STM. The mechanism behind this effect is commonly argued to act on item memory but not on order memory. The aim of the current study was to examine whether LTM could exert an influence on STM for order by examining an effect attributed to LTM, the phonological neighbourhood effect, in a task that reduced the requirement to retain item information. In Experiment 1, 18 participants completed a serial reconstruction task where neighbourhood density alternated within the lists. In Experiment 2, 22 participants completed a serial reconstruction task using pure lists of dense and sparse neighbourhood words. In Experiment 3, 22 participants completed a reconstruction task with both mixed and pure lists. There was a significant effect of neighbourhood density with better recall for dense than sparse neighbourhood words in pure lists but not in mixed lists. Results suggest that LTM exerts an influence prior to that proposed by many models of memory for order.     

The effects of unvocalized music on short-term memory

The studies reported here investigated the role of background music in verbal processing. The experiment was a partial replication of Salame and Baddeley (1989), where the effect of music on the recall of digits, was examined, but included an additional key condition where participants heard instrumental music without the words usually associated with it. In this case we used nursery rhymes. In addition, articulatory suppression was manipulated as a tool to look at the role of working memory in the task. The relationship between long-term memory and working memory was further explored by using an implicit memory task to examine verbal memory effects for words associated with the music but not actually heard. The results indicated that background, instrumental music, long-associated with words, significantly impairs concurrent verbal processing. These long-term memory effects on working memory were, however, not associated with implicit memory effects, and no priming was observed.     

The contribution of phonological short-term memory to artificial grammar learning

Three experiments investigated the contribution of phonological short-term memory (STM) to grammar learning by manipulating rehearsal during study of an auditory artificial grammar made up from a vocabulary of spoken Mandarin syllables. Experiment 1 showed that concurrent, irrelevant articulation impaired grammar learning compared with a nonverbal control task. Experiment 2 replicated and extended this finding, showing that repeating the grammatical strings at study improved grammar learning compared with suppressing rehearsal or remaining silent during learning. Experiment 3 found no effects of rehearsal on grammar learning once participants had learned the component syllables. The findings suggest that phonological STM aids artificial grammar learning via effects on vocabulary learning.     

The contribution of phonological short-term memory to artificial grammar learning

Three experiments investigated the contribution of phonological short-term memory (STM) to grammar learning by manipulating rehearsal during study of an auditory artificial grammar made up from a vocabulary of spoken Mandarin syllables. Experiment 1 showed that concurrent, irrelevant articulation impaired grammar learning compared with a nonverbal control task. Experiment 2 replicated and extended this finding, showing that repeating the grammatical strings at study improved grammar learning compared with suppressing rehearsal or remaining silent during learning. Experiment 3 found no effects of rehearsal on grammar learning once participants had learned the component syllables. The findings suggest that phonological STM aids artificial grammar learning via effects on vocabulary learning.     

A developmental phonological short-term memory deficit: a case study

A developmental case of phonological short-term memory deficit was studied in a highly educated subject. The subject, BS, who had obtained a Ph.D. in molecular biology, demonstrated striking deficits on some short-term memory tasks, particularly for auditorily presented nonword lists. With visual presentation and with meaningful words, he often scored at a normal level. The results indicate a deficit in retaining phonological information but an ability to use visual, lexical, and semantic information to boost recall. Despite this phonological short-term memory deficit, BS scored at a normal level on a syntactic comprehension test and on reading of nonwords. He was impaired, however, on repeated list learning, learning of foreign vocabulary, and transcribing dictated materials. The implications of these results for models of short-term memory and the uses of phonological retention in cognitive processing are discussed.     

Effects of music on memory for text

Previous research has suggested that the use of song can facilitate recall of text. This study examined the effect of repetition of a melody across verses, familiarity with the melody, rhythm, and other structural processing hypotheses to explain this phenomenon. Two experiments were conducted, each with 100 participants recruited from undergraduate Psychology programs (44 men, 156 women, M age = 28.5 yr., SD = 9.4). In Exp. 1, participants learned a four-verse ballad in one of five encoding conditions (familiar melody, unfamiliar melody, unknown rhythm, known rhythm, and spoken). Exp. 2 assessed the effect of familiarity in rhythm-only conditions and of pre-exposure with a previously unfamiliar melody. Measures taken were number of verbatim words recalled and number of lines produced with correct syllabic structure. Analysis indicated that rhythm, with or without musical accompaniment, can facilitate recall of text, suggesting that rhythm may provide a schematic frame to which text can be attached. Similarly, familiarity with the rhythm or melody facilitated recall. Findings are discussed in terms of integration and dual-processing theories.     

Deficits in verbal long-term memory and learning in children with poor phonological short-term memory skills

Possible links between phonological short-term memory and both longer term memory and learning in 8-year-old children were investigated in this study. Performance on a range of tests of long-term memory and learning was compared for a group of 16 children with poor phonological short-term memory skills and a comparison group of children of the same age with matched nonverbal reasoning abilities but memory scores in the average range. The low-phonological-memory group were impaired on longer term memory and learning tasks that taxed memory for arbitrary verbal material such as names and nonwords. However, the two groups performed at comparable levels on tasks requiring the retention of visuo-spatial information and of meaningful material and at carrying out prospective memory tasks in which the children were asked to carry out actions at a future point in time. The results are consistent with the view that poor short-term memory function impairs the longer term retention and ease of learning of novel verbal material.     

Deficits in verbal long-term memory and learning in children with poor phonological short-term memory skills

Possible links between phonological short-term memory and both longer term memory and learning in 8-year-old children were investigated in this study. Performance on a range of tests of long-term memory and learning was compared for a group of 16 children with poor phonological short-term memory skills and a comparison group of children of the same age with matched nonverbal reasoning abilities but memory scores in the average range. The low-phonological-memory group were impaired on longer term memory and learning tasks that taxed memory for arbitrary verbal material such as names and nonwords. However, the two groups performed at comparable levels on tasks requiring the retention of visuo-spatial information and of meaningful material and at carrying out prospective memory tasks in which the children were asked to carry out actions at a future point in time. The results are consistent with the view that poor short-term memory function impairs the longer term retention and ease of learning of novel verbal material.     

Effects of short-term memory contents on short-and long-term memory searches

The Ss memorized a long-term set (LT set) of 20 words before participating in a recognition memory test. On each trial Ss were given a new short-term set (ST set) of from one to four words or one to four digits. The Ss gave a positive response to a test item that was a member of either the ST or the LT set and gave a negative response to a test item not in either set; both words and digits were used as test stimuli. The results indicated that reaction time (RT) to positive test items from the ST set was an increasing function 0f the size of the ST set; the same was also true for negative responses to test digits when the ST set was composed of digits. RT to other test stimuli, however, did not depend on ST set size. These results are consistent with the view that Ss access long-term memory (LTM) and short-term memory (STM) simultaneously rather than sequentially. The results also showed that Ss responded more quickly to test items from the LT set when the ST set contained digits than when it contained words. Negative test items that were words, however, were rejected more slowly when the ST set contained digits than when it contained words. These results suggest that the search of LTM was affected by the contents of STM.     

Accessing short-term memory with semantic and phonological information: A time-course analysis

The time course for accessing short-term memory representations on the basis of item, phonological, and semantic information was measured with a speed-accuracy tradeoff (SAT) variant of a recognition probe task. Subjects studied 5-word lists and then judged whether a test word (1) was in the study list (item judgment); (2) rhymed with a word in the study list (rhyme judgment); or (3) was a synonym of a word in the study list (synonym judgment). Analysis of the SAT retrieval functions demonstrated that judgments based on phonological and semantic information were slower and less accurate than judgments based on composite item representations. The slower retrieval dynamics for rhyme and synonym judgments suggest that judgments based on component properties of the memory trace are mediated by either a generate or recall process distinct from the parallel or direct-access mechanism used in item judgments.     

The differential effect of background music on memory for verbal and visuospatial information

Background music is a part of our everyday activities. Considerable evidence suggests that listening to music while performing cognitive tasks may negatively influence performance. However, other studies have shown that it can benefit memory when the music played during the encoding of information is also provided during the retrieval of that information, in the so-called context dependent memory effect. Since controversial results may be attributed to the nature of the material to be memorized, the aim of the present study is to compare the potential effect of consistent background music on the immediate and long-term recall of verbal and visuospatial information. Experiment 1 showed that instrumental background music does not benefit nor decrease recall of a list of unrelated words, both at the immediate and the 48-hours-delayed tests. By contrast, Experiment 2 revealed that the same background music can impair immediate and therefore long-term memory for visuospatial information. Results are interpreted in terms of competition for neurocognitive resources, with tasks mostly relying on the same brain hemisphere competing for a limited set of resources. Hence, background music might impair visuospatial memory to a greater extent than verbal memory, in the context of limited capacity cognitive system. In conclusion, the nature of the material to be learnt must be considered to fully understand the effect of background music on memory.     

Effects of background music on the remembering of filmed events

The use of background music within films provides a naturalistic setting in which to investigate certain issues of schematic processing. Here, the relative placement of music was manipulated such that music either accompanied a scene's outcome, and thereby accentuated its affective meaning, or foreshadowed the same scene, and thereby created expectancies about the future course of events. In addition, background music was either congruent or incongruent with the affect of an episode's outcome. When subjects were later asked to recall the series of filmed episodes, results showed that expectancy violations arising from mood-incongruent relations led to better memory in the foreshadowing condition, while mood-congruent relations led to better performance in the accompanying condition. Results from a recognition task further revealed that scenes unavailable for recall could be recognized when cued by background music. These overall findings are discussed in terms of selective-attending processes that are differentially directed as a function of background music.     

Comparing the effects of aging and background noise on short-term memory performance

Paired associate recall was tested as a function of serial position for younger and older adults for five word pairs presented aurally in quiet and in noise. In Experiment 1, the addition of noise adversely affected recall in young adults, but only in the early serial positions. Experiments 2 and 3 suggested that the recall of older adults listening to the words in quiet was nearly equivalent to that of younger adults listening in noise. In Experiment 4, we determined the signal-to-noise ratio (S/N) such that, on average, younger and older adults were able to correctly hear the same percentage of words when words were presented one at a time in noise. In Experiment 5, younger adults were tested under this S/N. Compared with older adults from Experiment 3, younger adults in this experiment recalled more words at all serial positions. The results are interpreted as showing that encoding in secondary memory is impaired by aging and noise either as a function of degraded sensory representations, or as a function of reduced processing resources.     

A developmental deficit in short-term phonological memory: Implications for language and reading

Abstract

QU, an eight-year-old boy, was identified from a large scale normative study on the basis of his greatly reduced digit span, combined with normal long-term memory and non-verbal intelligence. Further investigation indicated that his visual STM was normal, but that he was clearly impaired on two verbal STM tests, nonword repetition, and memory span for words. His span showed clear effects of phonological similarity and word-length, suggesting qualitatively normal functioning of the phonological loop component of working memory, despite a quantitative impairment in level of performance. This pattern resembles that found in an earlier study of children with a specific language disorder. We tested QU on measures of vocabulary, syntax, and reading, and found him to be substantially below the age norms on all three. The implications of these findings are discussed for the role of the phonological loop in language development.     

Articulatory and phonological deficits in short-term memory and their relation to syntactic processing

The relationships between sentence comprehension deficits and deficits in the articulatory or phonological components of short-term memory were investigated. Nonfluent agrammatic patients showed very poor comprehension of syntax while a group of nonfluent patients who were not agrammatic showed good comprehension, despite both groups showing similar degrees of deficits in an articulatory component of memory. The results imply that a disruption of inner rehearsal has little consequence for auditory sentence comprehension, and that the syntactic comprehension deficits of the agrammatic patients could not be attributed to their memory deficit. A patient with a disruption in phonological storage showed good comprehension for many sentences, but was impaired when a difficult syntactic structure was encountered early in a sentence. It was proposed that phonological storage serves to hold words in a phonological form when sentence processing cannot keep pace with sentence input. Although a role for phonological storage was postulated, the impressive degree of syntactic processing that could be carried out by patients with very restricted memory spans implies that there is little overlap between the memory systems disrupted in these patients and the working memory system presumed to be involved in sentence comprehension.     

Effects of timbre and tempo change on memory for music

We investigated the effects of different encoding tasks and of manipulations of two supposedly surface parameters of music on implicit and explicit memory for tunes. In two experiments, participants were first asked to either categorize instrument or judge familiarity of 40 unfamiliar short tunes. Subsequently, participants were asked to give explicit and implicit memory ratings for a list of 80 tunes, which included 40 previously heard. Half of the 40 previously heard tunes differed in timbre (Experiment 1) or tempo (Experiment 2) in comparison with the first exposure. A third experiment compared similarity ratings of the tunes that varied in timbre or tempo. Analysis of variance (ANOVA) results suggest first that the encoding task made no difference for either memory mode. Secondly, timbre and tempo change both impaired explicit memory, whereas tempo change additionally made implicit tune recognition worse. Results are discussed in the context of implicit memory for nonsemantic materials and the possible differences in timbre and tempo in musical representations.