Subvocalization rate versus other predictors of the memory span

Two experiments were performed to determine how accurately the immediate memory span may be predicted from the subject's subvocalization rate, as compared with other subject and stimulus variables. In the first, span and free-recall measures were obtained for 24 subjects, each tested with four types of spoken material (nonsense syllables, random words, fourth-order approximations to English, and normal prose). Silent subvocalization rate, whispered subvocalization rate, speaking rate, and silent reading rate were also measured for each subject. The span (3.9-14 items) showed the highest zero-order correlation with silent subvocalization rate: r = .80. Multiple regression analysis confirmed this as the span's best predictor, partial r = .31. Similar results were found for free-recall scores. In Exp. 2 the digit span was correlated against measures of age, intelligence, subvocalization rate, perceptual speed, and memory search rate, for 40 subjects aged 7 to 17 yr. The best zero-order predictor was age (.62), followed by subvocalization rate (.57) and intelligence (.39). Multiple regression analysis indicated that the span was best predicted by age, partial r = .37, and subvocalization rate, partial r = .29. The span appears more closely related to subjects' internal speech rate than to other cognitive functions.     

Silent reading rate and memory span

This paper reports two experiments concerned with the form of the linear function relating memory span to pronunciation rate. Experiment 1 asked whether the intercept of the equation is attributable to an interaction between modality, word‐length, and serial position. The results lead us to reject this possibility. Experiment 2 examined the shape of the span function for visual presentation of lists read aloud or silently. The results show that the intercept of the span function disappears for silent presentation but not for aloud presentation. The results are discussed in terms of a balance between two opposing effects of word‐length.     

Silent reading rate and memory span

This paper reports two experiments concerned with the form of the linear function relating memory span to pronunciation rate. Experiment 1 asked whether the intercept of the equation is attributable to an interaction between modality, word-length, and serial position. The results lead us to reject this possibility. Experiment 2 examined the shape of the span function for visual presentation of lists read aloud or silently. The results show that the intercept of the span function disappears for silent presentation but not for aloud presentation. The results are discussed in terms of a balance between two opposing effects of word-length.     

Labeling, rehearsal, and short-term memory in retarded children

A short-term memory task was used to explore the effects of verbal labeling and rehearsal on serial-position recall in mildly retarded 9- to 11-year-old children. A stimulus array consisting of seven cards depicting familiar animals was presented for seven trials. In Expt I, recall when subjects labeled the pictures as they were shown was compared to recall when no labeling occurred. Total recall was not affected, but for the older CA group primacy recall was hindered and recency recall was facilitated by labeling. In Expt II, three variations of rehearsal of the names to be recalled were compared. When prompting accompanied rehearsal, recall improved at both recency and primacy positions. When prompting occurred for the primacy positions only, recall was higher for these positions but not for other positions. These results support the view that verbal skills affect recall in mildly retarded children similarly to normal children.     

Individual differences in memory span: The contribution of rehearsal, access to lexical memory,and output speed

Rehearsal speed has traditionally been seen to be the prime determinant of individual differences in memory span. Recent studies, in the main using young children as the subject population, have suggested other contributors to span performance, notably contributions from long-term memory and forgetting and retrieval processes occurring during recall. In the current research we explore individual differences in span with respect to measures of rehearsal, output time, and access to lexical memory.We replicate standard short-term phenomena; we show that the variables that influence children's span performance influence adult performance in the same way; and we show that lexical memory access appears to be a more potent source of individual differences in span than either rehearsal speed or output factors.     

Noise effects on rehearsal rate in short term serial order memory

Three experiments are reported which were designed to test the hypothesis that the rate of rehearsal during noise is slower than that under quiet conditions. The first experiment measured directly the rate of articulation while subjects either read or rehearsed a set of five consonants. It was shown that while the rate of articulation when reading aloud did not differ under the two noise levels [65 dB(C) and 85 dB(C)], rate of articulation during overt rehearsal in loud noise was significantly slower than under quiet conditions. In Experiment II a similar effect was demonstrated where words were required to be read or rehearsed; here it was shown that the greatest impairment due to noise was on the rate of rehearsal of words of long spoken length.

The third experiment showed that loud noise impaired recall performance more markedly for a set of words of long spoken length presented early on in the sequence than for a set of shorter words, even though both sets were equal in the number of syllables and phonemes they contained.

It was concluded that in verbal memory tasks where rote rehearsal of the to-be-remembered material is the predominant strategy for enhancing trace duration, noise may affect memory performance by slowing down the rehearsal rate.     

Speech rate and the development of short-term memory span

Two experiments are reported which examine the effects of word duration on memory span in subjects of different ages. The same linear function relating recall to speech rate (assessed by the speed of repeating words) fits the results of subjects ranging in age from 4 years old to adulthood. It is concluded that developmental increases in short-term memory span can be explained in terms of increases in speech rate and that there is no evidence for an increase in short-term memory capacity. Analyses of the children's speech suggests that increases in speech rate with age reflect increases in the speed of articulation of individual words, rather than any change in the duration of pauses between successive words or changes in coarticulation between words.     

Developmental changes in memory: The effects of processing time and rehearsal instructions

An overt rehearsal procedure was used to investigate the relationship between children's rehearsal strategies and free recall performance. Previous work has shown that developmental differences in rehearsal content, rather than rehearsal frequency, affect recall performance. This experiment investigated the effects of increased processing time and rehearsal training upon recall. Third-grade girls (age 8) were able to use additional processing time to increase the activity of their rehearsal, and they showed corresponding improvement in recall. In contrast, third-grade boys (age 8) and sixth-grade boys and girls (age 12) did not take advantage of a slower presentation rate to rehearse more actively, and their recall did not change. Further, even without additional processing time, both the third-grade boys and girls were able to use an instructed active rehearsal strategy to facilitate their recall. The direct manipulation of rehearsal activity and the resulting improvement in recall provide experimental support for the proposed relationship between rehearsal content and recall from long-term memory store.     

The association between auditory memory span and speech rate in children from kindergarten to sixth grade.

This study reexamined the association between speech rate and memory span in children from kindergarten to sixth grade (N = 152) in order to potentially account for the inconsistencies within the published literature on this topic. Some of the inconsistencies in past research may reflect the different methods adopted in assessing speech rate. In particular, repeating word triples may itself involve memory demands, contaminating the correlation between speech rate and memory span in younger children. Analyses using composite speech rate and memory span measures showed that speech rate for word triples shared variance with memory span that was independent of speech rate for single words. Moreover, speech rate for word triples was largely redundant with age in explaining additional variation in memory span once the effects of speech rate for single words were controlled.     

A within-subjects analysis of the relationship between memory span and processing rate in short-term memory

A within-subjects analysis of the relationship between memory span and processing rate for four stimulus classes in short-term memory indicated that while the two factors are correlated when averaged data is considered, as shown by Cavanagh (Psychological Review, 1972, 79, 525–530), the strength of the relationship for individual subjects varies from zero to unity. The intersubject correlations for each stimulus class were not consistent with the view that a unified model may be advanced to account for performance in recall and recognition tasks in shortterm memory.     

Temporal grouping, rehearsal and short-term memory

The effects of temporal grouping on auditory short-term memory are investigated, using pauses of different lengths to indicate the groups. No quantitative or qualitative differences were found between the shorter and longer pauses. This result, in conjunction with an analysis of the order errors, is used to suggest what kind of processing occurs during the pauses. This processing is selective, recoding the information about order according to position within a group.     

Item concreteness vs spatial organization as predictors of visual imagery

The relative contributions of item concreteness and interitem spatial organization to recall processes were studied by attempting to induce modality-specific interference between recall and response. Separate groups of 12 Ss learned lists of items that varied in physical or referential visual characteristics. They later signaled information about them either vocally or via a visually guided response. Some ways of presenting lists for learning that are traditionally regarded as increasing reliance on mediating imagery were effective in generating conflict between recall and the visually guided response. This effectiveness was limited to presentation conditions and list types that introduced spatial organization into the stimulus material. The concreteness of individual items was not useful in predicting visual conflict.     

Articulatory rehearsal and phonological storage in working memory

The theoretical distinction between an articulatory control process and a short-term phonological store was supported in five experiments on immediate serial recall. In Experiment 1, articulatory suppression during the presentation and recall of auditory material abolished the word length effect but not the phonemic similarity effect. In Experiment 2, the two latter effects were found to be independent with auditory presentation. In Experiment 3, the effects of irrelevant speech and word length were found to be independent with visual presentation. In Experiment 4, articulatory suppression during the presentation and recall of auditory material abolished the phonemic similarity effect with a slow presentation rate. Nevertheless, in Experiment 5, articulatory suppression with a conventional presentation rate did not reduce the effect of phonemic similarity, even when a 10-sec interval was interposed between presentation and recall. These results indicate that the encoding, maintenance, and retrieval of spoken material within the phonological store do not depend on a process of articulatory rehearsal.     

The role of rehearsal and generation in false memory creation

The current research investigated one possible mechanism underlying false memories in the Deese-Roediger-McDermott (DRM) paradigm. In the DRM paradigm, participants who study lists of related words (e.g., “table, sitting, bench …”) frequently report detailed memories for the centrally related but non-presented critical lure (e.g., “chair”). One possibility is that participants covertly call to mind the critical non-presented lure during the study phase, and later misattribute memory for this internally generated event to its external presentation. To investigate this, the DRM paradigm was modified to allow collection of on-line thoughts during the study phase. False recognition increased following generation during study. False recognition also increased following study of longer lists; this effect was partially explained by the fact that longer lists were more likely to elicit generations of the critical lure during study. Generation of the lure during study contributes to later false recognition, although it does not explain the entire effect.     

The effects of processing time and processing rate on forgetting in working memory: Testing four models of the complex span paradigm

Four models of working memory processes in the complex span paradigm were tested: The task-switching model of Towse, Hitch, and Hutton (1998), the interference account of Saito and Miyake (2004), and two versions of the time-based resource-sharing model of Barrouillet, Bernardin, and Camos (2004). On the basis of a reading span paradigm that used segmented sentences, the effect of processing time on the recall of words was investigated while the amount of processing was held constant. Two conditions of reading (continuous vs. normal) were compared in order to study the influence of brief pauses during reading that could be used for articulatory rehearsal. The results favor a version of the time-based resource-sharing model: A faster reading rate had a negative effect on recall. The effect of reading rate was obtained with continuous as well as normal reading, revealing that even continuous articulation does not prevent simultaneous refreshing of memory traces. A second experiment showed that continuous reading made concurrent articulatory rehearsal virtually impossible. These findings imply that a second rehearsal mechanism for verbal working memory, other than articulatory rehearsal, exists.     

Determining spatial span: The role of movement time and articulation rate

In studies of verbal memory span individual differences in speech rate have been found to predict the number of items that can be recalled in order. This is thought to happen because overt speech rate is related to the rate of internal verbal rehearsal. For spatial span there may also be an internal rehearsal system linked to overt responding, and if there is a strong analogy to be drawn between the verbal and spatial domains, then movement time between spatial targets should predict the number of spatial locations that can be recalled. In the first study reported, none of the six measures of movement time did predict spatial span, but, as expected, speech rate predicted verbal span. In addition, speech rate predicted spatial span. In a second study the use of articulatory suppression during span presentation showed that verbal span dropped, but was still predicted by speech rate. Spatial span was again predicted by the time it took to say digits rather than the time it took to make movements to spatial targets. There would not seem to be any simple analogy between the limitations on verbal span and those on spatial span. In addition, the relationship between speech rate and sequential memory performance may be more complex than previous studies have suggested.     

Short-term memory deficits in reading disabled children,in the absence of opportunity for rehearsal strategies

Two groups of reading-disabled (RD) children were compared with controls (age- and IQ-matched competent readers), on a serial running memory task. The unknown (to the subject) length of the serial lists coupled with high rates of presentation, made it impossible for the children to use systematic rehearsal strategies in this task. Both groups of RD children performed reliably worse than their controls. From the data, it is argued that the short-term memory deficits exhibited by the RD children should not be attributed to an inability to rehearse, nor to an inability to encode (recognize) items, but rather to an inability to encode serial items in the form of serial phonological patterns.