I am a developmental and clinical psychologist with particular interests in working memory, executive functioning and witness skills in children with intellectual and developmental disabilities. Address: Language and Communication Science
City Univeristy London
Northampton Square
London EC1V 0HG
UK
Quarterly Journal of Experimental Psychology, 2012
Three experiments addressed controversies in the previous literature on the development of phonol... more Three experiments addressed controversies in the previous literature on the development of phonological and other forms of short-term memory coding in children, using assessments of picture memory span that ruled out potentially confounding effects of verbal input and output. Picture materials were varied in terms of phonological similarity, visual similarity, semantic similarity, and word length. Older children (6/8-year-olds), but not younger children (4/5-year-olds), demonstrated robust and consistent phonological similarity and word length effects, indicating that they were using phonological coding strategies. This confirmed findings initially reported by Conrad (1971), but subsequently questioned by other authors. However, in contrast to some previous research, little evidence was found for a distinct visual coding stage at 4 years, casting doubt on assumptions that this is a developmental stage that consistently precedes phonological coding. There was some evidence for a dual visual and phonological coding stage prior to exclusive use of phonological coding at around 5-6 years. Evidence for semantic similarity effects was limited, suggesting that semantic coding is not a key method by which young children recall lists of pictures.
Background
The purpose of the current cross-sectional study was to examine the developmental pro... more Background
The purpose of the current cross-sectional study was to examine the developmental progression in working memory (WM) between the ages of 9 and 16 years in a large sample of children with mild to borderline intellectual disabilities (MBID). Baddeley's influential WM model was used as a theoretical framework. Furthermore, the relations between WM on the one hand, and scholastic skills (arithmetic and reading) on the other were examined.
Method
One hundred and ninety-seven children with MBID between 9 and 16 years old participated in this study. All children completed several tests measuring short-term memory, WM, inhibition, arithmetic and single word reading.
Results
WM, visuospatial short-term memory and inhibition continued to develop until around age 15 years. However verbal short-term memory showed no further developmental increases after the age of 10 years. Verbal short-term memory was associated with single word reading, whereas inhibition was associated with arithmetic.
Discussion
The finding that verbal short-term memory ceases to develop beyond the age of 10 years in children with MBID contrasts with results of studies involving typically developing children, where verbal short-term memory develops until around age 15 years. This relative early developmental plateau might explain why verbal short-term memory is consistently considered weak in children with MBID.
Williams (WS) and Down (DS) syndromes have been associated with specifically compromised short-te... more Williams (WS) and Down (DS) syndromes have been associated with specifically compromised short-term memory (STM) subsystems. Individuals with WS have shown impairments in visuospatial STM, while individuals with DS have often shown problems with the recall of verbal material. However, studies have not usually compared the development of STM skills in these domains, in these populations. The present study employed a cross-sectional developmental trajectories approach, plotting verbal and visuospatial STM performance against more general cognitive and chronological development, to investigate how the domain-specific skills of individuals with WS and DS may change as development progresses, as well as whether the difference between STM skill domains increases, in either group, as development progresses. Typically developing children, of broadly similar cognitive ability to the clinical groups, were also included. Planned between- and within-group comparisons were carried out. Individuals with WS and DS both showed the domain-specific STM weaknesses in overall performance that were expected based on the respective cognitive profiles. However, skills in both groups developed, according to general cognitive development, at similar rates to those of the TD group. In addition, no significant developmental divergence between STM domains was observed in either clinical group according to mental age or chronological age,
although the general pattern of findings indicated that the influence of the latter variable across STM domains, particularly in WS, might merit further investigation.
A relatively quick, face-to-face, adaptive working memory training
intervention was assessed in ... more A relatively quick, face-to-face, adaptive working memory training
intervention was assessed in 5- to 8-year-old typically developing
children, randomly allocated to a 6-week intervention condition, or
an active control condition. All children received 18 sessions of 10
minutes, three times/week for 6 weeks. Assessments of six working memory skills, word reading and mathematics were administered at pre-test, post-test and 6-month follow-up. Additional measures of word reading, mathematics, spelling and reading comprehension were given at a 12-month follow-up. At post-test, the trained group showed significantly larger gains than the control group on the two trained executive-loaded working memory tasks (Listening Recall and Odd One Out Span) and on two untrained working memory tasks (Word Recall and Counting Recall). These ‘near transfer’ effects were still apparent at 6-month follow-up. ‘Far transfer’ effects were less evident: there was no difference between the groups in their gains on single word reading and mathematics over 12months, and spelling skills did not differ at 12-month follow-up. However, the trained group showed significantly higher reading comprehension scores than the control group at 12-month follow-up. Thus, improving the ability to divide attention between processing and storage may have had specific benefits for reading comprehension.
Despite the large number of people with intellectual disabilities (ID) and the fact they are more... more Despite the large number of people with intellectual disabilities (ID) and the fact they are more likely to be victims and witnesses of crime, only two published studies have investigated their performance on identification line-up parades. In the present study we examined the identification performance of adults with and
without ID on both a perpetrator-present and a perpetrator-absent photographic line-up. In addition, we investigated factors that could explain any potential difficulties with identification performance, such as face recognition performance (as measured by a standardised test), eyewitness confidence, understanding of the purpose of a line-up, and memory for non-biased line-up instructions. In comparison with typical adults, participants with ID demonstrated poorer performance across both perpetrator-present and perpetrator-absent photographic line-ups, yet were more confident in the accuracy of their responses. In addition they had poorer face recognition performance, were less likely to understand the purpose of the line-up, and were less likely to remember the non-biased line-up instructions. This pattern of difficulties is discussed in relation to the development of future research and interventions.
Williams (WS) and Down (DS) syndromes are characterised by roughly opposing ability profiles. Rel... more Williams (WS) and Down (DS) syndromes are characterised by roughly opposing ability profiles. Relative verbal strengths and visuospatial difficulties have been reported in those with WS, while expressive language difficulties have been observed in individuals with DS. Few investigations into the executive function (EF) skills of these groups have examined the effect of verbal/visuospatial task type on performance. Analogous verbal and visuospatial measures were administered to these populations within four EF domains: executive-loaded working memory (ELWM), inhibition, fluency and set-shifting. Performance in both groups was compared to that of typically developing (TD) children using regression techniques controlling for potentially influential cognitive/developmental factors. Individuals with WS showed the expected relative visuospatial difficulties, as indicated by poorer performance than TD individuals, on tests of ELWM and fluency.
Individuals with DS displayed the expected relative verbal difficulty in the domain of setshifting. In addition, each population showed pervasive deficits across modality in one domain; ELWMfor individuals with DS, and inhibition for individuals with WS. Individuals with WS and DS showed EF difficulties in comparison to a TD group, but, their executive performance was affected by EF task type (verbal/visuospatial) and EF domain in different
ways. While the findings indicated that EF in these populations is characterised by a range of specific strengths and weaknesses, it was also suggested that the relative verbal/visuospatial strengths associated with each population do not consistentlymanifest across EF domains. Lastly, syndrome specificity was indicated by the differences in groups’ performance patterns.
The aim of the present study was to investigate executive functions in adults with intellectual d... more The aim of the present study was to investigate executive functions in adults with intellectual disability, and compare them to a closely matched control group longitudinally for 5 years. In the Betula database, a group of adults with intellectual disability (ID, n=46) was defined from measures of verbal and nonverbal IQ. A control group, with two people for every person with intellectual disability (n=92), was chosen by matching on the following criterion in order of priority: IQ higher than 85, age, sex, sample, level of education, and years of education. 3 types of tasks of executive functions were included on 2 occasions, with 5 years between testing sessions: The Tower of Hanoi, executively loaded dual task versions of word recall, and verbal fluency. Adults with ID showed significant impairments on verbal fluency and on the executively loaded dual task word recall task (at encoding but not at recall). There were no group differences on the Tower of Hanoi. No significant differences between the 2 test occasions were found. The results are interpreted in terms of individuals with ID having problems with speed of accessing lexical items and difficulties with working memory-related executive control at encoding, which includes shifting between tasks. There are, however, not necessarily problems with inhibition. The dual task results additionally imply that the adults with intellectual disability were more sensitive to strategy interruptions at encoding, but that dividing attention at recall did not have such detrimental effects.
An investigation was carried out into the phonological short-term memory (PSTM) and visuospatial ... more An investigation was carried out into the phonological short-term memory (PSTM) and visuospatial short-term memory (VSSTM) skills of children with specific language impairment (n=41) using memory span tasks. Individuals with SLI were compared to children who had milder degrees of language difficulty (‘low language functioning’, LLF, n=31), and children with typical development (n=88). Regression analyses examined the effects of group after controlling for age and non-verbal IQ; further regressions included an additional control for verbal IQ. Even after controlling for all of these variables, children with SLI and LLF showed significantly weaker PSTM than children with typical development. For VSSTM, there were no overall group differences in performance. The findings imply that the PSTM difficulties that have been reported in children with SLI are substantial, whereas VSSTM appears to be an area of relative strength for most children with SLI.
Children with intellectual disability (ID) were given a comprehensive range of executive function... more Children with intellectual disability (ID) were given a comprehensive range of executive functioning measures, which systematically varied in terms of verbal and non-verbal demands. Their performance was compared to the performance of groups matched on mental age (MA) and chronological age (CA), respectively. Twenty-two children were included in each group. Children with ID performed on par with the MA group on switching, verbal executive-loaded working memory and most fluency tasks, but below the MA group on inhibition, planning, and non-verbal executive-loaded working memory. Children with ID performed below CA comparisons on all the executive tasks. We suggest that children with ID have a specific profile of executive functioning, with MA appropriate abilities to generate new exemplars (fluency) and to switch attention between tasks, but difficulties with respect to inhibiting pre-potent responses, planning, and non-verbal executive-loaded working memory. The development of different types of executive functioning skills may, to different degrees, be related to mental age and experience.
Abstract
Background. A limited range of evidence suggests that children with SLI have difficult... more Abstract
Background. A limited range of evidence suggests that children with SLI have difficulties with higher order thinking and reasoning skills (executive functioning, EF). This study involved a comprehensive investigation of EF in this population taking into account the contributions of age, non-verbal IQ and verbal ability.
Methods. 10 separate measures of EF were assessed in 160 children: 41 had SLI; 31 had low language/cognitive functioning but did not fulfil the criteria for SLI (LLF); and 88 were typically-developing with no language difficulties. Group differences in performance were assessed after controlling for age, non-verbal IQ and verbal ability in a series of regression analyses.
Results. Children with SLI and LLF had significantly lower performance than typical children on six out of the 10 EF tasks once age and non-verbal IQ had been controlled (verbal and non-verbal executive-loaded working memory; verbal and non-verbal fluency; non-verbal inhibition; non-verbal planning). Performance on these EF tasks remained lower for those in the SLI group even when verbal IQ was entered in the regressions.
Conclusions. Children with language impairments showed marked difficulties on a range of EF tasks. These difficulties were present even when adjustments were made for their verbal abilities.
Background. Although children with intellectual disabilities (ID) often provide accurate witness ... more Background. Although children with intellectual disabilities (ID) often provide accurate witness testimony, jurors tend to perceive their witness statements to be inherently unreliable.
Method. The current study explored the free recall transcripts of child witnesses with ID who had watched a video clip, relative to those of typically developing (TD) age-matched children, and
assessed how mock jurors perceived these transcripts in the absence of knowledge of group (ID or TD) membership. A further aim of this research was to determine whether perceptions of credibility were associated with levels of free recall and witness characteristics (anxiety and mental age).
Results. Mock jurors rated the testimony of children with ID as less credible than that of a TD age-matched comparison group.This was largely because of the transcripts of the children with ID containing fewer details than those of the TD children.
Anxiety and mental age were found to have no effect on perceived levels of credibility.
Conclusions. It appears that even in the absence of knowledge of whether a child does or does not have ID, this factor still affects perceptions of credibility among mock jurors. Our findings suggest that fundamental differences in the quality of the witness transcripts lead to lower perceptions of credibility
for children with ID.
Background There is little previous research examining whether measures of working memory are rel... more Background There is little previous research examining whether measures of working memory are related to educational achievement in children with intellectual disabilities (ID).
Methods A battery of working memory and achievement measures was administered to 11- to 12-year-old children with ID; younger typically developing children of comparable mental age were also assessed.
Results The working memory measures that assessed phonological short-term memory (PSTM) accounted for the most variance in reading and spelling in children with ID, whereas the working memory measures that assessed central executiveloaded working memory (CELWM) accounted for the most variance in number skills.These relationships were broadly similar among typically developing children.
Conclusions Compensatory strategies for weak PSTM may help to improve reading and spelling skills in children with ID, whereas reducing CELWM loads may be more helpful in aiding their number skills.
Keywords working memory, educational achievement, intellectual disabilities, children
Background: Executive functioning is increasingly seen as incorporating several component sub-ski... more Background: Executive functioning is increasingly seen as incorporating several component sub-skills and clinical assessments should reflect this complexity.
Method: Tools for assessing executive functioning in children are reviewed within five key areas, across verbal and visuospatial abilities, with emphasis on batteries of tests.
Results: There are many appropriate tests for children, although the choice is more limited for those under the age of 8 years.
Conclusions: Whilst there are several batteries of executive functioning suitable for children, clinicians may prefer to cherry-pick from a broader range of measures that assess specific components of executive functioning.
We asked whether children with autism are specifically impaired on tests of working memory. Exper... more We asked whether children with autism are specifically impaired on tests of working memory. Experiment 1 showed that children with autism were at least as likely as normal children to employ articulatory rehearsal (criterion: evincing the "word length effect") and that they ...
Quarterly Journal of Experimental Psychology, 2012
Three experiments addressed controversies in the previous literature on the development of phonol... more Three experiments addressed controversies in the previous literature on the development of phonological and other forms of short-term memory coding in children, using assessments of picture memory span that ruled out potentially confounding effects of verbal input and output. Picture materials were varied in terms of phonological similarity, visual similarity, semantic similarity, and word length. Older children (6/8-year-olds), but not younger children (4/5-year-olds), demonstrated robust and consistent phonological similarity and word length effects, indicating that they were using phonological coding strategies. This confirmed findings initially reported by Conrad (1971), but subsequently questioned by other authors. However, in contrast to some previous research, little evidence was found for a distinct visual coding stage at 4 years, casting doubt on assumptions that this is a developmental stage that consistently precedes phonological coding. There was some evidence for a dual visual and phonological coding stage prior to exclusive use of phonological coding at around 5-6 years. Evidence for semantic similarity effects was limited, suggesting that semantic coding is not a key method by which young children recall lists of pictures.
Background
The purpose of the current cross-sectional study was to examine the developmental pro... more Background
The purpose of the current cross-sectional study was to examine the developmental progression in working memory (WM) between the ages of 9 and 16 years in a large sample of children with mild to borderline intellectual disabilities (MBID). Baddeley's influential WM model was used as a theoretical framework. Furthermore, the relations between WM on the one hand, and scholastic skills (arithmetic and reading) on the other were examined.
Method
One hundred and ninety-seven children with MBID between 9 and 16 years old participated in this study. All children completed several tests measuring short-term memory, WM, inhibition, arithmetic and single word reading.
Results
WM, visuospatial short-term memory and inhibition continued to develop until around age 15 years. However verbal short-term memory showed no further developmental increases after the age of 10 years. Verbal short-term memory was associated with single word reading, whereas inhibition was associated with arithmetic.
Discussion
The finding that verbal short-term memory ceases to develop beyond the age of 10 years in children with MBID contrasts with results of studies involving typically developing children, where verbal short-term memory develops until around age 15 years. This relative early developmental plateau might explain why verbal short-term memory is consistently considered weak in children with MBID.
Williams (WS) and Down (DS) syndromes have been associated with specifically compromised short-te... more Williams (WS) and Down (DS) syndromes have been associated with specifically compromised short-term memory (STM) subsystems. Individuals with WS have shown impairments in visuospatial STM, while individuals with DS have often shown problems with the recall of verbal material. However, studies have not usually compared the development of STM skills in these domains, in these populations. The present study employed a cross-sectional developmental trajectories approach, plotting verbal and visuospatial STM performance against more general cognitive and chronological development, to investigate how the domain-specific skills of individuals with WS and DS may change as development progresses, as well as whether the difference between STM skill domains increases, in either group, as development progresses. Typically developing children, of broadly similar cognitive ability to the clinical groups, were also included. Planned between- and within-group comparisons were carried out. Individuals with WS and DS both showed the domain-specific STM weaknesses in overall performance that were expected based on the respective cognitive profiles. However, skills in both groups developed, according to general cognitive development, at similar rates to those of the TD group. In addition, no significant developmental divergence between STM domains was observed in either clinical group according to mental age or chronological age,
although the general pattern of findings indicated that the influence of the latter variable across STM domains, particularly in WS, might merit further investigation.
A relatively quick, face-to-face, adaptive working memory training
intervention was assessed in ... more A relatively quick, face-to-face, adaptive working memory training
intervention was assessed in 5- to 8-year-old typically developing
children, randomly allocated to a 6-week intervention condition, or
an active control condition. All children received 18 sessions of 10
minutes, three times/week for 6 weeks. Assessments of six working memory skills, word reading and mathematics were administered at pre-test, post-test and 6-month follow-up. Additional measures of word reading, mathematics, spelling and reading comprehension were given at a 12-month follow-up. At post-test, the trained group showed significantly larger gains than the control group on the two trained executive-loaded working memory tasks (Listening Recall and Odd One Out Span) and on two untrained working memory tasks (Word Recall and Counting Recall). These ‘near transfer’ effects were still apparent at 6-month follow-up. ‘Far transfer’ effects were less evident: there was no difference between the groups in their gains on single word reading and mathematics over 12months, and spelling skills did not differ at 12-month follow-up. However, the trained group showed significantly higher reading comprehension scores than the control group at 12-month follow-up. Thus, improving the ability to divide attention between processing and storage may have had specific benefits for reading comprehension.
Despite the large number of people with intellectual disabilities (ID) and the fact they are more... more Despite the large number of people with intellectual disabilities (ID) and the fact they are more likely to be victims and witnesses of crime, only two published studies have investigated their performance on identification line-up parades. In the present study we examined the identification performance of adults with and
without ID on both a perpetrator-present and a perpetrator-absent photographic line-up. In addition, we investigated factors that could explain any potential difficulties with identification performance, such as face recognition performance (as measured by a standardised test), eyewitness confidence, understanding of the purpose of a line-up, and memory for non-biased line-up instructions. In comparison with typical adults, participants with ID demonstrated poorer performance across both perpetrator-present and perpetrator-absent photographic line-ups, yet were more confident in the accuracy of their responses. In addition they had poorer face recognition performance, were less likely to understand the purpose of the line-up, and were less likely to remember the non-biased line-up instructions. This pattern of difficulties is discussed in relation to the development of future research and interventions.
Williams (WS) and Down (DS) syndromes are characterised by roughly opposing ability profiles. Rel... more Williams (WS) and Down (DS) syndromes are characterised by roughly opposing ability profiles. Relative verbal strengths and visuospatial difficulties have been reported in those with WS, while expressive language difficulties have been observed in individuals with DS. Few investigations into the executive function (EF) skills of these groups have examined the effect of verbal/visuospatial task type on performance. Analogous verbal and visuospatial measures were administered to these populations within four EF domains: executive-loaded working memory (ELWM), inhibition, fluency and set-shifting. Performance in both groups was compared to that of typically developing (TD) children using regression techniques controlling for potentially influential cognitive/developmental factors. Individuals with WS showed the expected relative visuospatial difficulties, as indicated by poorer performance than TD individuals, on tests of ELWM and fluency.
Individuals with DS displayed the expected relative verbal difficulty in the domain of setshifting. In addition, each population showed pervasive deficits across modality in one domain; ELWMfor individuals with DS, and inhibition for individuals with WS. Individuals with WS and DS showed EF difficulties in comparison to a TD group, but, their executive performance was affected by EF task type (verbal/visuospatial) and EF domain in different
ways. While the findings indicated that EF in these populations is characterised by a range of specific strengths and weaknesses, it was also suggested that the relative verbal/visuospatial strengths associated with each population do not consistentlymanifest across EF domains. Lastly, syndrome specificity was indicated by the differences in groups’ performance patterns.
The aim of the present study was to investigate executive functions in adults with intellectual d... more The aim of the present study was to investigate executive functions in adults with intellectual disability, and compare them to a closely matched control group longitudinally for 5 years. In the Betula database, a group of adults with intellectual disability (ID, n=46) was defined from measures of verbal and nonverbal IQ. A control group, with two people for every person with intellectual disability (n=92), was chosen by matching on the following criterion in order of priority: IQ higher than 85, age, sex, sample, level of education, and years of education. 3 types of tasks of executive functions were included on 2 occasions, with 5 years between testing sessions: The Tower of Hanoi, executively loaded dual task versions of word recall, and verbal fluency. Adults with ID showed significant impairments on verbal fluency and on the executively loaded dual task word recall task (at encoding but not at recall). There were no group differences on the Tower of Hanoi. No significant differences between the 2 test occasions were found. The results are interpreted in terms of individuals with ID having problems with speed of accessing lexical items and difficulties with working memory-related executive control at encoding, which includes shifting between tasks. There are, however, not necessarily problems with inhibition. The dual task results additionally imply that the adults with intellectual disability were more sensitive to strategy interruptions at encoding, but that dividing attention at recall did not have such detrimental effects.
An investigation was carried out into the phonological short-term memory (PSTM) and visuospatial ... more An investigation was carried out into the phonological short-term memory (PSTM) and visuospatial short-term memory (VSSTM) skills of children with specific language impairment (n=41) using memory span tasks. Individuals with SLI were compared to children who had milder degrees of language difficulty (‘low language functioning’, LLF, n=31), and children with typical development (n=88). Regression analyses examined the effects of group after controlling for age and non-verbal IQ; further regressions included an additional control for verbal IQ. Even after controlling for all of these variables, children with SLI and LLF showed significantly weaker PSTM than children with typical development. For VSSTM, there were no overall group differences in performance. The findings imply that the PSTM difficulties that have been reported in children with SLI are substantial, whereas VSSTM appears to be an area of relative strength for most children with SLI.
Children with intellectual disability (ID) were given a comprehensive range of executive function... more Children with intellectual disability (ID) were given a comprehensive range of executive functioning measures, which systematically varied in terms of verbal and non-verbal demands. Their performance was compared to the performance of groups matched on mental age (MA) and chronological age (CA), respectively. Twenty-two children were included in each group. Children with ID performed on par with the MA group on switching, verbal executive-loaded working memory and most fluency tasks, but below the MA group on inhibition, planning, and non-verbal executive-loaded working memory. Children with ID performed below CA comparisons on all the executive tasks. We suggest that children with ID have a specific profile of executive functioning, with MA appropriate abilities to generate new exemplars (fluency) and to switch attention between tasks, but difficulties with respect to inhibiting pre-potent responses, planning, and non-verbal executive-loaded working memory. The development of different types of executive functioning skills may, to different degrees, be related to mental age and experience.
Abstract
Background. A limited range of evidence suggests that children with SLI have difficult... more Abstract
Background. A limited range of evidence suggests that children with SLI have difficulties with higher order thinking and reasoning skills (executive functioning, EF). This study involved a comprehensive investigation of EF in this population taking into account the contributions of age, non-verbal IQ and verbal ability.
Methods. 10 separate measures of EF were assessed in 160 children: 41 had SLI; 31 had low language/cognitive functioning but did not fulfil the criteria for SLI (LLF); and 88 were typically-developing with no language difficulties. Group differences in performance were assessed after controlling for age, non-verbal IQ and verbal ability in a series of regression analyses.
Results. Children with SLI and LLF had significantly lower performance than typical children on six out of the 10 EF tasks once age and non-verbal IQ had been controlled (verbal and non-verbal executive-loaded working memory; verbal and non-verbal fluency; non-verbal inhibition; non-verbal planning). Performance on these EF tasks remained lower for those in the SLI group even when verbal IQ was entered in the regressions.
Conclusions. Children with language impairments showed marked difficulties on a range of EF tasks. These difficulties were present even when adjustments were made for their verbal abilities.
Background. Although children with intellectual disabilities (ID) often provide accurate witness ... more Background. Although children with intellectual disabilities (ID) often provide accurate witness testimony, jurors tend to perceive their witness statements to be inherently unreliable.
Method. The current study explored the free recall transcripts of child witnesses with ID who had watched a video clip, relative to those of typically developing (TD) age-matched children, and
assessed how mock jurors perceived these transcripts in the absence of knowledge of group (ID or TD) membership. A further aim of this research was to determine whether perceptions of credibility were associated with levels of free recall and witness characteristics (anxiety and mental age).
Results. Mock jurors rated the testimony of children with ID as less credible than that of a TD age-matched comparison group.This was largely because of the transcripts of the children with ID containing fewer details than those of the TD children.
Anxiety and mental age were found to have no effect on perceived levels of credibility.
Conclusions. It appears that even in the absence of knowledge of whether a child does or does not have ID, this factor still affects perceptions of credibility among mock jurors. Our findings suggest that fundamental differences in the quality of the witness transcripts lead to lower perceptions of credibility
for children with ID.
Background There is little previous research examining whether measures of working memory are rel... more Background There is little previous research examining whether measures of working memory are related to educational achievement in children with intellectual disabilities (ID).
Methods A battery of working memory and achievement measures was administered to 11- to 12-year-old children with ID; younger typically developing children of comparable mental age were also assessed.
Results The working memory measures that assessed phonological short-term memory (PSTM) accounted for the most variance in reading and spelling in children with ID, whereas the working memory measures that assessed central executiveloaded working memory (CELWM) accounted for the most variance in number skills.These relationships were broadly similar among typically developing children.
Conclusions Compensatory strategies for weak PSTM may help to improve reading and spelling skills in children with ID, whereas reducing CELWM loads may be more helpful in aiding their number skills.
Keywords working memory, educational achievement, intellectual disabilities, children
Background: Executive functioning is increasingly seen as incorporating several component sub-ski... more Background: Executive functioning is increasingly seen as incorporating several component sub-skills and clinical assessments should reflect this complexity.
Method: Tools for assessing executive functioning in children are reviewed within five key areas, across verbal and visuospatial abilities, with emphasis on batteries of tests.
Results: There are many appropriate tests for children, although the choice is more limited for those under the age of 8 years.
Conclusions: Whilst there are several batteries of executive functioning suitable for children, clinicians may prefer to cherry-pick from a broader range of measures that assess specific components of executive functioning.
We asked whether children with autism are specifically impaired on tests of working memory. Exper... more We asked whether children with autism are specifically impaired on tests of working memory. Experiment 1 showed that children with autism were at least as likely as normal children to employ articulatory rehearsal (criterion: evincing the "word length effect") and that they ...
European Journal of Cognitive Psychology, Jan 1, 1993
Page 1. EUROPEAN JOURNAL OF COGNITIVE PSYCHOLOGY, 1993,5 (3) 241-287 Why Does Memory Span Improve... more Page 1. EUROPEAN JOURNAL OF COGNITIVE PSYCHOLOGY, 1993,5 (3) 241-287 Why Does Memory Span Improve with Age? A Review of the Evidence for Two Current Hypotheses Lucy A. Henry Department of Psychology ...
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The purpose of the current cross-sectional study was to examine the developmental progression in working memory (WM) between the ages of 9 and 16 years in a large sample of children with mild to borderline intellectual disabilities (MBID). Baddeley's influential WM model was used as a theoretical framework. Furthermore, the relations between WM on the one hand, and scholastic skills (arithmetic and reading) on the other were examined.
Method
One hundred and ninety-seven children with MBID between 9 and 16 years old participated in this study. All children completed several tests measuring short-term memory, WM, inhibition, arithmetic and single word reading.
Results
WM, visuospatial short-term memory and inhibition continued to develop until around age 15 years. However verbal short-term memory showed no further developmental increases after the age of 10 years. Verbal short-term memory was associated with single word reading, whereas inhibition was associated with arithmetic.
Discussion
The finding that verbal short-term memory ceases to develop beyond the age of 10 years in children with MBID contrasts with results of studies involving typically developing children, where verbal short-term memory develops until around age 15 years. This relative early developmental plateau might explain why verbal short-term memory is consistently considered weak in children with MBID.
although the general pattern of findings indicated that the influence of the latter variable across STM domains, particularly in WS, might merit further investigation.
intervention was assessed in 5- to 8-year-old typically developing
children, randomly allocated to a 6-week intervention condition, or
an active control condition. All children received 18 sessions of 10
minutes, three times/week for 6 weeks. Assessments of six working memory skills, word reading and mathematics were administered at pre-test, post-test and 6-month follow-up. Additional measures of word reading, mathematics, spelling and reading comprehension were given at a 12-month follow-up. At post-test, the trained group showed significantly larger gains than the control group on the two trained executive-loaded working memory tasks (Listening Recall and Odd One Out Span) and on two untrained working memory tasks (Word Recall and Counting Recall). These ‘near transfer’ effects were still apparent at 6-month follow-up. ‘Far transfer’ effects were less evident: there was no difference between the groups in their gains on single word reading and mathematics over 12months, and spelling skills did not differ at 12-month follow-up. However, the trained group showed significantly higher reading comprehension scores than the control group at 12-month follow-up. Thus, improving the ability to divide attention between processing and storage may have had specific benefits for reading comprehension.
without ID on both a perpetrator-present and a perpetrator-absent photographic line-up. In addition, we investigated factors that could explain any potential difficulties with identification performance, such as face recognition performance (as measured by a standardised test), eyewitness confidence, understanding of the purpose of a line-up, and memory for non-biased line-up instructions. In comparison with typical adults, participants with ID demonstrated poorer performance across both perpetrator-present and perpetrator-absent photographic line-ups, yet were more confident in the accuracy of their responses. In addition they had poorer face recognition performance, were less likely to understand the purpose of the line-up, and were less likely to remember the non-biased line-up instructions. This pattern of difficulties is discussed in relation to the development of future research and interventions.
Individuals with DS displayed the expected relative verbal difficulty in the domain of setshifting. In addition, each population showed pervasive deficits across modality in one domain; ELWMfor individuals with DS, and inhibition for individuals with WS. Individuals with WS and DS showed EF difficulties in comparison to a TD group, but, their executive performance was affected by EF task type (verbal/visuospatial) and EF domain in different
ways. While the findings indicated that EF in these populations is characterised by a range of specific strengths and weaknesses, it was also suggested that the relative verbal/visuospatial strengths associated with each population do not consistentlymanifest across EF domains. Lastly, syndrome specificity was indicated by the differences in groups’ performance patterns.
Background. A limited range of evidence suggests that children with SLI have difficulties with higher order thinking and reasoning skills (executive functioning, EF). This study involved a comprehensive investigation of EF in this population taking into account the contributions of age, non-verbal IQ and verbal ability.
Methods. 10 separate measures of EF were assessed in 160 children: 41 had SLI; 31 had low language/cognitive functioning but did not fulfil the criteria for SLI (LLF); and 88 were typically-developing with no language difficulties. Group differences in performance were assessed after controlling for age, non-verbal IQ and verbal ability in a series of regression analyses.
Results. Children with SLI and LLF had significantly lower performance than typical children on six out of the 10 EF tasks once age and non-verbal IQ had been controlled (verbal and non-verbal executive-loaded working memory; verbal and non-verbal fluency; non-verbal inhibition; non-verbal planning). Performance on these EF tasks remained lower for those in the SLI group even when verbal IQ was entered in the regressions.
Conclusions. Children with language impairments showed marked difficulties on a range of EF tasks. These difficulties were present even when adjustments were made for their verbal abilities.
Method. The current study explored the free recall transcripts of child witnesses with ID who had watched a video clip, relative to those of typically developing (TD) age-matched children, and
assessed how mock jurors perceived these transcripts in the absence of knowledge of group (ID or TD) membership. A further aim of this research was to determine whether perceptions of credibility were associated with levels of free recall and witness characteristics (anxiety and mental age).
Results. Mock jurors rated the testimony of children with ID as less credible than that of a TD age-matched comparison group.This was largely because of the transcripts of the children with ID containing fewer details than those of the TD children.
Anxiety and mental age were found to have no effect on perceived levels of credibility.
Conclusions. It appears that even in the absence of knowledge of whether a child does or does not have ID, this factor still affects perceptions of credibility among mock jurors. Our findings suggest that fundamental differences in the quality of the witness transcripts lead to lower perceptions of credibility
for children with ID.
Keywords children, credibility, eyewitness
testimony, intellectual disabilities, juror perceptions
Methods A battery of working memory and achievement measures was administered to 11- to 12-year-old children with ID; younger typically developing children of comparable mental age were also assessed.
Results The working memory measures that assessed phonological short-term memory (PSTM) accounted for the most variance in reading and spelling in children with ID, whereas the working memory measures that assessed central executiveloaded working memory (CELWM) accounted for the most variance in number skills.These relationships were broadly similar among typically developing children.
Conclusions Compensatory strategies for weak PSTM may help to improve reading and spelling skills in children with ID, whereas reducing CELWM loads may be more helpful in aiding their number skills.
Keywords working memory, educational achievement, intellectual disabilities, children
Method: Tools for assessing executive functioning in children are reviewed within five key areas, across verbal and visuospatial abilities, with emphasis on batteries of tests.
Results: There are many appropriate tests for children, although the choice is more limited for those under the age of 8 years.
Conclusions: Whilst there are several batteries of executive functioning suitable for children, clinicians may prefer to cherry-pick from a broader range of measures that assess specific components of executive functioning.
The purpose of the current cross-sectional study was to examine the developmental progression in working memory (WM) between the ages of 9 and 16 years in a large sample of children with mild to borderline intellectual disabilities (MBID). Baddeley's influential WM model was used as a theoretical framework. Furthermore, the relations between WM on the one hand, and scholastic skills (arithmetic and reading) on the other were examined.
Method
One hundred and ninety-seven children with MBID between 9 and 16 years old participated in this study. All children completed several tests measuring short-term memory, WM, inhibition, arithmetic and single word reading.
Results
WM, visuospatial short-term memory and inhibition continued to develop until around age 15 years. However verbal short-term memory showed no further developmental increases after the age of 10 years. Verbal short-term memory was associated with single word reading, whereas inhibition was associated with arithmetic.
Discussion
The finding that verbal short-term memory ceases to develop beyond the age of 10 years in children with MBID contrasts with results of studies involving typically developing children, where verbal short-term memory develops until around age 15 years. This relative early developmental plateau might explain why verbal short-term memory is consistently considered weak in children with MBID.
although the general pattern of findings indicated that the influence of the latter variable across STM domains, particularly in WS, might merit further investigation.
intervention was assessed in 5- to 8-year-old typically developing
children, randomly allocated to a 6-week intervention condition, or
an active control condition. All children received 18 sessions of 10
minutes, three times/week for 6 weeks. Assessments of six working memory skills, word reading and mathematics were administered at pre-test, post-test and 6-month follow-up. Additional measures of word reading, mathematics, spelling and reading comprehension were given at a 12-month follow-up. At post-test, the trained group showed significantly larger gains than the control group on the two trained executive-loaded working memory tasks (Listening Recall and Odd One Out Span) and on two untrained working memory tasks (Word Recall and Counting Recall). These ‘near transfer’ effects were still apparent at 6-month follow-up. ‘Far transfer’ effects were less evident: there was no difference between the groups in their gains on single word reading and mathematics over 12months, and spelling skills did not differ at 12-month follow-up. However, the trained group showed significantly higher reading comprehension scores than the control group at 12-month follow-up. Thus, improving the ability to divide attention between processing and storage may have had specific benefits for reading comprehension.
without ID on both a perpetrator-present and a perpetrator-absent photographic line-up. In addition, we investigated factors that could explain any potential difficulties with identification performance, such as face recognition performance (as measured by a standardised test), eyewitness confidence, understanding of the purpose of a line-up, and memory for non-biased line-up instructions. In comparison with typical adults, participants with ID demonstrated poorer performance across both perpetrator-present and perpetrator-absent photographic line-ups, yet were more confident in the accuracy of their responses. In addition they had poorer face recognition performance, were less likely to understand the purpose of the line-up, and were less likely to remember the non-biased line-up instructions. This pattern of difficulties is discussed in relation to the development of future research and interventions.
Individuals with DS displayed the expected relative verbal difficulty in the domain of setshifting. In addition, each population showed pervasive deficits across modality in one domain; ELWMfor individuals with DS, and inhibition for individuals with WS. Individuals with WS and DS showed EF difficulties in comparison to a TD group, but, their executive performance was affected by EF task type (verbal/visuospatial) and EF domain in different
ways. While the findings indicated that EF in these populations is characterised by a range of specific strengths and weaknesses, it was also suggested that the relative verbal/visuospatial strengths associated with each population do not consistentlymanifest across EF domains. Lastly, syndrome specificity was indicated by the differences in groups’ performance patterns.
Background. A limited range of evidence suggests that children with SLI have difficulties with higher order thinking and reasoning skills (executive functioning, EF). This study involved a comprehensive investigation of EF in this population taking into account the contributions of age, non-verbal IQ and verbal ability.
Methods. 10 separate measures of EF were assessed in 160 children: 41 had SLI; 31 had low language/cognitive functioning but did not fulfil the criteria for SLI (LLF); and 88 were typically-developing with no language difficulties. Group differences in performance were assessed after controlling for age, non-verbal IQ and verbal ability in a series of regression analyses.
Results. Children with SLI and LLF had significantly lower performance than typical children on six out of the 10 EF tasks once age and non-verbal IQ had been controlled (verbal and non-verbal executive-loaded working memory; verbal and non-verbal fluency; non-verbal inhibition; non-verbal planning). Performance on these EF tasks remained lower for those in the SLI group even when verbal IQ was entered in the regressions.
Conclusions. Children with language impairments showed marked difficulties on a range of EF tasks. These difficulties were present even when adjustments were made for their verbal abilities.
Method. The current study explored the free recall transcripts of child witnesses with ID who had watched a video clip, relative to those of typically developing (TD) age-matched children, and
assessed how mock jurors perceived these transcripts in the absence of knowledge of group (ID or TD) membership. A further aim of this research was to determine whether perceptions of credibility were associated with levels of free recall and witness characteristics (anxiety and mental age).
Results. Mock jurors rated the testimony of children with ID as less credible than that of a TD age-matched comparison group.This was largely because of the transcripts of the children with ID containing fewer details than those of the TD children.
Anxiety and mental age were found to have no effect on perceived levels of credibility.
Conclusions. It appears that even in the absence of knowledge of whether a child does or does not have ID, this factor still affects perceptions of credibility among mock jurors. Our findings suggest that fundamental differences in the quality of the witness transcripts lead to lower perceptions of credibility
for children with ID.
Keywords children, credibility, eyewitness
testimony, intellectual disabilities, juror perceptions
Methods A battery of working memory and achievement measures was administered to 11- to 12-year-old children with ID; younger typically developing children of comparable mental age were also assessed.
Results The working memory measures that assessed phonological short-term memory (PSTM) accounted for the most variance in reading and spelling in children with ID, whereas the working memory measures that assessed central executiveloaded working memory (CELWM) accounted for the most variance in number skills.These relationships were broadly similar among typically developing children.
Conclusions Compensatory strategies for weak PSTM may help to improve reading and spelling skills in children with ID, whereas reducing CELWM loads may be more helpful in aiding their number skills.
Keywords working memory, educational achievement, intellectual disabilities, children
Method: Tools for assessing executive functioning in children are reviewed within five key areas, across verbal and visuospatial abilities, with emphasis on batteries of tests.
Results: There are many appropriate tests for children, although the choice is more limited for those under the age of 8 years.
Conclusions: Whilst there are several batteries of executive functioning suitable for children, clinicians may prefer to cherry-pick from a broader range of measures that assess specific components of executive functioning.