Biomedical subjects

C Hulme

Publications and source records attributed to C Hulme.

At least 19 recordsLinked to original sources

PubMed1997

Segmentation, not rhyming, predicts early progress in learning to read.

We present a longitudinal study of children in the first two years of learning to read. A battery of tests of phonological skills administered when the children were prereaders identified two distinct and relatively independent factors, Rhyming (defined by measures of rhyme detection and rhyme production) and Segmentation (defined by measures of phoneme identification and phoneme deletion). Segmentation was strongly correlated with attainment in reading and spelling at the end of the first year at school, though Rhyming was not. In addition, letter name knowledge predicted both reading and spelling skill and showed an interactive effect with children's segmentation skills. By the end of the second year of school, however, rhyming had started to exert a predictive effect of spelling, but not on reading. The results are discussed in the context of current theories of the role of phonological skills in learning to read.

Achievement↗

PubMed1997

Word-frequency effects on short-term memory tasks: evidence for a redintegration process in immediate serial recall.

Four experiments investigated the mechanisms responsible for the advantage enjoyed by high-frequency words in short-term memory tasks. Experiment 1 demonstrated effects of word frequency on memory span that were independent of differences in speech rate. Experiments 2 and 3 showed that word frequency has an increasing effect on serial recall across serial positions, but Experiment 4 showed that this effect was abolished for backward recall. A model that includes a redintegration process that operates to "clean up" decayed short-term memory traces is proposed, and the multinomial processing tree model described by R. Schweickert (1993) is used to provide a quantitative fit to data from Experiments 2, 3, and 4.

Adult↗

PubMed1997

Social drinking and laughter.

Pairs of observers monitored drinking and laughter in groups of social drinkers (N = 56). A significant correlation of .27 was found between units of alcohol consumed and laughter scores.

Adolescent↗

PubMed1996

The Automatic Activation of Sound-Letter Knowledge: An Alternative Interpretation of Analogy and Priming Effects in Early Spelling Development

This paper presents two experiments investigating 6-year-old children's use of analogy in spelling. In Experiment 1, children make analogies between a visible clue word and a similar sounding target word. Analogies are made to the same extent regardless of whether the clue and target share a rime unit, a consonant vowel (CV) or a vowel but are not made when only common letters are shared. A second experiment investigates children's spelling by analogy when the clue word is not visible. Again, an equal number of analogies are made between words sharing a rime unit, a CV or a vowel. From the earliest stages of learning to spell, children benefit from drawing analogies (at the level of individual phonemes) with words that they know. These findings are related to recent connectionist models of the development of reading and spelling skills.

Journal Article↗

PubMed1996

The remediation of clumsiness. I: An evaluation of Laszlo's kinaesthetic approach.

The effectiveness of a kinaesthetic training programme proposed by Laszlo for children with movement difficulties was evaluated by comparing two groups of 10 'clumsy' children matched pairwise on age, IQ and sex as well as degree of kinaesthetic and motor impairment. Tests of kinaesthetic ability, using the Parameter Estimation by Sequential Testing (PEST) procedure, and motor competence administered before and after treatment revealed an improvement in both groups on all measures but no differential effect of the training programme. Immediately after training, the changes we obtained in motor performance were confined to balance skills but, at follow up, 3 months later, changes in manual and ball skills were also evident. This unusual pattern of change requires replication. Our findings forced us to consider the possibility that any effect of Laszlo's recommended training programme had been obscured by our use of the PEST procedure, which had in itself facilitated motor learning.

Case-Control Studies↗

PubMed1996

The remediation of clumsiness. II. Is kinaesthesis the answer?

The paper reports the second of two studies designed to evaluate the effectiveness of the Kinaesthetic Training Programme (Laszlo and Bairstow, 1985) for children with movement difficulties. Three groups of 12 children were matched on age, IQ and sex as well as degree of kinaesthetic and motor impairment. One group received the Laszlo training, another received a training programme designed to avoid explicit reference to kinaesthesis and the third group received no training. Children receiving no intervention failed to show a change in performance. By contrast, the motor competence of both groups of treated children improved significantly. There was no advantage for the Laszlo trained group. It seems that in designing a remediation programme for clumsy children, the way that training is presented is as important as its actual content.

Activities of Daily Living↗

PubMed1996

Modelling human memory: connectionism and convolution.

The mathematical operation of convolution is used as an associative mechanism by several recent influential models of human memory. Convolution can be used to associate two vectors (representing items to be remembered) into a memory trace vector in one operation. An approximation to either of the input vectors can then be retrieved, using the other vector as a probe. Recent convolution-based memory models have accounted for a wide range of data. Connectionist models may have greater potential for providing developmental accounts, but the architectures that have been most widely used to account for developmental phenomena cannot perform one-trial learning and this has limited their use as models of human memory. We show that a connectionist-like architecture can learn, using a gradient-descent algorithm, to perform single-trial learning in a similar manner to convolution. The solution that the network finds leads to less variable retrieval than does convolution. Furthermore, the network can learn to carry out the convolution operation itself. This provides a link between connectionist and convolution approaches, and a basis for models with many of the attractions of both connectionist and convolution approaches.

Humans↗

PubMed1995

Novel 2- and 5-azido-N-(diphenylcarbamoyl)proline methyl esters. Examples of a novel proline oxidation.

The crystal structures of two azido-substituted proline derivatives are reported. Racemic 2-azido-1-(diphenyl-carbamoyl)proline methyl ester, (I), C19H19N5O3, is resolved upon crystallization from methylene chloride-diethyl ether. The azido moieties are nonlinear with N--N--N angles of 173 (1) and 170.3 (2) degrees for (I) and (II) [cis-5-azido-N-(diphenylcarbamoyl)proline methyl ester, C19H19N5O3], respectively. Close intramolecular contacts between the carbonyl O atom of the amide and the central N atom of the azido group are found. The contact distances between N7 and O14 are 2.780 (14) and 2.815 (2) A for (I) and (II), respectively.

Crystallography, X-Ray↗

PubMed1995

Mathematical and connectionist models of human memory: a comparison.

Recent convolution-based models of human memory (e.g. Lewandowsky & Murdock, 1989), have accounted for a wide range of data. However such models require the relevant mathematical operations to be provided to the network. Connectionist models, in contrast, have generally addressed different data, and not all architectures are appropriate for modelling single-trial learning. Furthermore, they tend to exhibit catastrophic interference in multiple list learning. In this paper we compare the ability of convolution-based models and DARNET (Developmental Associative Recall NETwork), to account for human memory data. DARNET is a connectionist approach to human memory in which the system gradually learns to associate vectors, in one trial, into a memory trace vector. Either of the vectors can than be retrieved. It is shown that the new associative mechanism can be used to account for a wide range of relevant experimental data as successfully as can convolution-based models with the same higher-level architectures. Limitations of the models are also addressed.

Computer Simulation↗

PubMed1995

Practitioner review: verbal working memory development and its disorders.

Working memory refers to the systems responsible for the temporary storage and manipulation of information during the performance of cognitive tasks. There is a good deal of evidence that verbal short-term memory functions as a working memory system. We review advances in our understanding of the nature and limitations of verbal short-term memory and the reasons for its development with age, and go on to consider the common association between impairments of verbal short-term memory and other impairments of cognitive development. We conclude by considering the relationship between short-term memory development and cognitive development.

Adolescent↗

PubMed1995

A comparison of phonological skills in children with reading comprehension difficulties and children with decoding difficulties.

This paper examines phonological skills in children with two distinct forms of reading difficulty: comprehension problems and decoding problems. In the first study a group of children with normal decoding skills but poor reading comprehension skills was studied. These children were found to have age-appropriate phonological skills. It is argued that normal phonological skills have enabled them to develop proficient decoding skills. A second study assessed the phonological skills of a group of children with decoding difficulties. These children showed marked deficits on tests of phonological skills. It appears that weak phonological skills underlie these children's decoding difficulties.

Child↗

PubMed1994

The development of phonological skills.

In this paper we consider the nature and consequences of the development of phonological skills in children. We begin with evidence for developmental refinements in phonological processes. These developments, in turn, affect a variety of other skills. We consider two particular examples: the relationship between the development of speech skills and verbal short-term memory and the development of children's phonological awareness. The development of phonological awareness is related to the acquisition of literacy, which, in turn, brings about further refinements in phonological skills.

Child↗

PubMed1994

Learning to read: the role of short-term memory and phonological skills.

This study investigates the relationships between reading, short-term memory and phonological skills, and the mechanisms responsible for the short-term memory differences found between groups of children differing in reading ability. Differences were found between groups of good, average, and poor readers in verbal, but not visual, short-term memory and these differences were well explained in terms of differences in speech rate (an index of rehearsal rate) between the groups. Measures of phonological ability, rhyme awareness and phoneme deletion, also showed strong differences between the different reading ability groups. Regression analyses showed that rhyme awareness, phoneme deletion, and speech rate (but not verbal short-term memory) had independent predictive relationships to reading skill. These findings show that phonological skills do not represent a unitary trait, and that different facets of phonological ability are important in predicting the development of reading skills.

Child↗

PubMed1994

The effects of phonetic similarity and list length on children's sound categorization performance.

Three experiments investigating children's performance on tests of sound categorization are reported. In two experiments, the children had to decide which was the "odd one out" in a sequence of three, four, and five words. In each case the "oddity" judgement required selecting the word which differed in its final consonant, producing a different rime segment. The odd word differed either by one phonetic feature (voice or place) or by both voice and place, from the others in the sequence. Oddity judgements were easier when the odd word was phonetically dissimilar to the background items but, contrary to expectation, performance did not decline as list length increased. Experiment 3 extended these findings by showing that place-only changes were more difficult than voice-only changes. Sound categorization performance correlated with memory span for words, but memory span did not make an independent contribution to sound categorization once age and reading skills had been controlled. The experiments show that the sound categorization task taps individual differences in speech perception mechanisms but that memory load is less crucial to this task than has often been supposed.

Age Factors↗

PubMed1994

Cell suicide in the developing nervous system: a functional neural network model.

A computational model of programmed cell death (PCD) in the nervous system is described. A neurobiologically realisable method for identifying and removing the least useful cells from a network is developed, and it is shown by simulation that an artificial neural network can solve difficult problems efficiently if it is given more neurons initially than it needs subsequently. The least useful neurons die off gradually after learning is complete, and the learned solution can then be maintained with a smaller number of units than were needed for initial learning. The research suggests a functional role for PCD, and how self-limiting PCD could be achieved in real neural systems.

Apoptosis↗

PubMed1994

Word recognition in developmental dyslexia: a connectionist interpretation.

We present a study of the accuracy, consistency, and speed of word naming in a dyslexic boy, JM, who has severe impairments in the ability to use sub-lexical, phonological reading strategies. For words that he can recognise, JM's naming latencies do not differ from those of control subjects matched for reading age, and he is generally consistent from one occasion to the next. He can also match printed homophones with their definitions--a skill that requires access to well-specified orthographic representations. The data are interpreted as evidence for the creation of efficient recognition devices for words within JM's sight vocabulary. However, he shows a continuing inability to use phonological decoding strategies to deal with words that he cannot recognize by sight. Overall we argue our results pose problems for stage models of reading development, and that they may best be interpreted within a connectionist framework of the development of word recognition skills.

Adolescent↗

PubMed1994

Comments on the use of a dichromophoric circular dichroism assay for the identification of beta-turns in peptides.

Use of the dichromophoric CD assay for beta-turn formation in peptide sequences has been investigated. The assay involves the observation of Cotton effects in CD spectra, originating from the approach of N- and C-terminal aromatic chromophores in tetrapeptides. The approach of the chromophores was believed to be brought about by a beta-turn in the peptide structure. Our investigations were paralleled by NMR studies which revealed the presence of a previously unreported hydrogen bond in the beta-turn conformers, which appears to play a role in the generation of the observed Cotton effects. This suggests caution in the use of the CD technique alone as an assay for beta-turn conformers in peptides.

Amino Acid Sequence↗

PubMed1994

Effects of word frequency and age of acquisition on short-term memory span.

The experiments reported examine the effects of two highly related variables, word frequency and age of acquisition, on short-term memory span. Short-term memory span and speech rate were measured for sets of words which independently manipulated frequency and age of acquisition. It was found that frequency had a considerable effect on short-term memory span, which was not mediated by speech rate differences--although frequency did affect speech rate in one experiment. For age of acquisition, this situation was reversed; there was a small but significant effect of age of acquisition on speech rate, but no effect on memory span. This occurred despite results confirming that the stimuli used in the experiments produce an effect of age of acquisition on word naming. The results are discussed in terms of a two-component view of performance on short-term memory tasks.

Aging↗