An exploratory factor analysis of the cognitive functioning of first-year bachelor students with dyslexia

An increasing number of students with dyslexia register in higher education. As a consequence, information on their pattern of strengths and weaknesses is essential to construct adequate assessment and diagnostic protocols. In a sample of 100 first-year bachelor students with dyslexia and 100 control students, a large pool of cognitive skills were tested using a variety of tests. When we applied an exploratory factor analysis to scores, a model with ten factors fitted the data best. Effect sizes were used to express the processing costs of students with dyslexia. The factors related to reading, spelling, flashed orthography, phonology, naming, math, and reading fluency resulted in large effect sizes. A factor combining all measures for crystallized IQ had a medium effect size. The subtests for fluid intelligence were divided in two separate constructs. Relationships between all subtest scores are visualized and interpreted in a general theoretical and practical framework.     

Reciprocal effects between fluid and crystallized intelligence and their dependence on parents' socioeconomic status and education

The investment theory of Cattell supposes an influence of fluid on crystallized intelligence. The development of fluid intelligence largely depends on biological factors, of crystallized intelligence on fluid intelligence and environmental stimulation. To test this theory two contrasting samples representing a broad ability range were chosen, a Brazilian sample (ages 7 to 15, N = 833, mean IQ 92) and a sample with a higher ability level in Germany (ages 11 to 19, N = 722, IQ 118). Analyses of cross-lagged effects across two year intervals show similar effects of fluid intelligence on crystallized and vice versa (around β = .17). Parental socioeconomic status and parental education have in both samples a slightly stronger effect on crystallized than on fluid intelligence. The first result refutes Cattell's theory, the second gives some support. The development of fluid intelligence also seems to be influenced by non-biological environmental factors resulting in a concept of intelligence as a malleable ability.     

Cognition and classroom quality as predictors of math achievement in the kindergarten year

Using a sample of 171 children, we examined classroom quality as a potential moderator of the link between three distinct but related aspects of cognition (fluid intelligence, crystallized intelligence, and executive functioning) and math achievement across the kindergarten year. Multilevel modeling analyses were conducted to account for nesting of students within classrooms. Results revealed significant aptitude by treatment interactions for fluid and crystallized intelligence, suggesting that classroom practices may affect children differently depending on their abilities. Children with higher levels of fluid intelligence and of crystallized intelligence fared better in higher quality classrooms. Results also provide some support for Cattell's investment hypothesis. Implications of the results are discussed.     

Fluid/spatial and crystallized intelligence in relation to domain-specific working memory: A latent-variable approach

Fluid/spatial intelligence, crystallized intelligence and their relationships to verbal and visuospatial working memory (WM) were studied. A total of 120 Finnish Air Force recruits participated in this study. Fluid/spatial intelligence was assessed using four different tasks, while crystallized intelligence was defined with the help of test scores of Finnish upper secondary school National Matriculation Tests in three different academic subjects and one additional Verbal Relations task. Complex WM span tasks were used to measure visuospatial and verbal WM capacities. Structural equation modeling indicated that verbal WM was related to crystallized intelligence when both WM tasks were included in the model, whereas performance on the visuospatial WM task was related to fluid/spatial intelligence, but not to crystallized intelligence. Verbal WM was not related to fluid intelligence when used as a single WM predictor. The results indicate that verbal WM might be related to verbal ability and learning at school, while visuospatial WM is relatively strongly related to nonverbal reasoning and spatial visualization. The current results further suggest that WM capacity is not a unitary system.     

Self estimates of general,crystallized, and fluid intelligences in an ethnically diverse population

Self-estimated intelligence is a quick way to assess people's conceptions of their own abilities. Furnham (2001) and colleagues have used this technique to make comparisons across culture and gender and different approaches to intelligence (such as g or Multiple Intelligences). This study seeks to build on past work in two ways. First, a large, diverse sample (N = 2309) enables the study of self-estimated intelligence across ethnicity. Second, one of the most prominent accepted intelligence theories is the Cattell–Horn–Carroll (CHC) theory. Can laypeople distinguish between general, fluid, and crystallized intelligence? This study finds evidence for a “modesty bias” in Hispanic Americans. In addition, fluid and crystallized intelligences may simply be seen as general intelligence (particularly by Caucasians and males).     

Orthographic knowledge predicts reading and spelling skills over and above general intelligence and phonological awareness

It is widely accepted that general intelligence and phonological awareness contribute to children’s acquisition of reading and spelling skills. A further candidate in this regard is orthographic knowledge (i.e., the knowledge about permissible letter patterns). It consists of two components, word-specific (i.e., the knowledge of the spelling of specific words) and general orthographic knowledge (i.e., the knowledge about legal letter patterns of a writing system). Among German students, previous studies have shown that word-specific orthographic knowledge contributes to both reading and spelling. The results regarding general orthographic knowledge and its contribution to reading and spelling are inconsistent. The major goal of the present study was to determine the incremental predictive value of orthographic knowledge for reading and spelling skills among German elementary-school children (N = 66), over and above the contribution of general intelligence and phonological awareness. The second goal was to examine whether there is a difference between the two subtypes of orthographic knowledge in the amount of their respective contribution to reading and spelling performance. The results show that word-specific as well as general orthographic knowledge contribute to both reading and spelling performance, over and above intelligence and phonological awareness. Furthermore, it reveals that both word-specific and general orthographic knowledge explain more variance of spelling compared to reading. Possible explanations for these results, limitations, and implications of the study are being discussed.

     

Increases in the verbal and fluid cognitive abilities of disadvantaged children attending preschool in the Netherlands

The current longitudinal study examined the development of general cognitive abilities of 4–6-year-old children of low-income, ethnic-minority families in preschool over two and a half years by determining the changes in general, and in verbal and fluid cognitive abilities, relative to age norms, using an intelligence test. The results revealed significant increases over time, relative to age norms, in full scale and in both verbal and fluid intelligence test scores of disadvantaged children, with medium effect sizes. These gains in measured intelligence were moderated by children's home language and age. Children who gained most also profited most from their increased abilities with respect to emergent school skills. Gains in verbal intelligence predicted emergent school vocabulary, but gains in fluid intelligence did not. Overall, gains in fluid intelligence predicted emergent math skills, and gains in verbal intelligence predicted emergent math skills only among older children.     

Subjective and Objective Intellectual Change in Older Adults

In this longitudinal study, 108 older individuals (M age = 70.58 years, SD = 6.94) estimated the extent to which their fluid and crystallized skills had changed over the previous three years. For each perceived change, individuals also estimated the extent to which numerous explanatory factors were responsible for such change. Crystallized skills were seen as unchanging, whereas fluid skills were perceived as having declined slightly. In both cases, self-initiated efforts to maintain one's skills were endorsed most frequently as explanations for the maintenance of one's skills. Variability in attributions in three-year changes in both fluid and crystallized skills was associated with individual differences in health, self perceived everyday cognitive failures, and state anxiety. The findings from this study suggest that it is important to identify factors over which older adults perceive themselves as having control as salient targets for educational interventions fostering a sense of self-efficacy, critical to feelings of enhanced competence in later life.     

How poor readers and spellers use interactive speech in a computerized spelling program

The ‘Spello’ program was designed to use interactive speech feedback on a talking-computer system to improve children's spelling and phonological skills. In two versions of the program, the synthesizer pronounced the word to be spelled and the student tried to type in the word correctly. Both versions of the program showed the students which letters were correct in their spelling attempts. One version pronounced only the target word, as often as the child requested. The other version also provided intermediate speech feedback for children's spelling attempts, so they could hear how their own attempts sounded, and compare them to the target word. Twenty-eight children aged seven to fourteen studied 16 words they had misspelled on pretests and 16 words of related word structure. For children ten years or older, training with intermediate speech feedback led to greater benefits in phonological coding skills than training with word-only feedback, reflected in the ability to read nonsense words related in structure to the trained words. Intermediate speech feedback also led to a marginally significant advantage in spelling the trained words. When the groups switched conditions, however, there was no difference in their tested skills after a second week of training.     

Effects of Consistency and Age of Acquisition on Reading and Spelling among Developing Readers

Three experiments investigated the effects of rime consistency on reading and spelling among developing readers ranging in age from 7 to 11 years. Experiment 1 found that children read words with inconsistent feedforward mappings between orthography and phonology (O → P) less accurately than consistent words. OP consistency interacted with chronological age, word frequency and age-of-acquisition (AoA). The effect of OP consistency on reading was larger for younger children than for older children and OP consistency had an effect for low frequency words and late-acquired words only. Experiment 2 found an effect of feedforward consistency between phonology and orthography (P → O) on children’s spelling but no interaction between PO consistency and AoA. Experiment 3 showed that the effects of feedforward consistency are independent of feedback consistency. Our results challenge models of reading and spelling that assume feedforward consistency effects are influenced by the frequency of exposure to words only and we suggest that interactions between consistency and AoA depends on the ratio of consistent to inconsistent OP mappings.     

The Armed Services Vocational Aptitude Battery (ASVAB): Little more than acculturated learning (Gc)!?

The Armed Services Vocational Aptitude Battery (ASVAB) is administered to over 1 million participants in the USA each year, serving either as a screening test for military enlistees or as a guidance counseling device in high schools. In this paper, we examine the factorial composition of the ASVAB in relation to the theory of fluid and crystallized intelligence and Carroll's [1993. Human cognitive abilities: a survey of factor-analytic studies. New York: Cambridge Univ. Press.] three-stratum model. In two studies (N=349, N=6751), participants were administered both the ASVAB and tests designed to measure factors underlying these (largely) analogous models. Exploratory and confirmatory factor analyses (CFA) of correlational data suggested that the ASVAB primarily measures acculturated learning [crystallized intelligence (Gc)]. This evidence does not support the frequent claim that this test measures psychometric g. Our conclusion is that the ASVAB should be revised to incorporate the assessment of additional broad cognitive ability factors, particularly fluid intelligence and learning and memory constructs, if it is to maintain its postulated function.     

Metacognitive factors in scientific problem-solving strategies

The aim of this study on 42 seventh graders (ages 12–13) was to determine whether and to what extent students’ metacognitive level is linked to their conceptualization and performance in problem solving at school, especially science problems. This hypothesis is supported by a number of studies showing that metacognition is a factor in learning. Two indexes were devised for the study: an index of metaknowledge about classroom learning, and an index of metacognitive monitoring in relation to task difficulty on a non-academic problem. These two indexes were related to the students’ intelligence test scores and solving strategies on electricity problems. The results showed that (1) the metaknowledge level was more closely tied to crystallized intelligence (Gc), and (2) metacognitive monitoring was more closely associated with fluid intelligence (Gf). Moreover, both metacognitive indexes were strongly linked to scientific problem-solving strategies (correlations around .50).     

Intelligence and the tuning-in of brain networks

The phase-synchronization of Gamma-band oscillations has been postulated as a mechanism of “network binding” and implicated in various aspects of perception, memory, and cognition. The current study investigates a possible link between Gamma synchrony and individual differences in intelligence within the theory of fluid and crystallized intelligence, with due reference to Hebbian theory. The hypothesis is that there are significant correlations between cognitive performance and synchronous Gamma activity across diverse brain regions. EEG data were recorded from 35 healthy participants, and the peak magnitude and latency of early and late Gamma Synchrony were extracted using a method for quantifying phase synchronization across multiple sites. Participants also completed 11 diverse cognitive ability tests tapping fluid and crystallized intelligence. Overall, moderate-sized correlations were obtained between accuracy and speed composite scores, derived from the ability tests, and magnitude and latency indices of Gamma synchrony. Phase-synchronous Gamma activity provides a plausible physiological mechanism that might account for individual differences in cognitive abilities.     

Explorations of crystallized intelligence: Completion tests,cloze tests,and knowledge

An attempt is made to reconcile two historically important tools for the assessment of intelligence and the prediction of academic achievement with extant theories of verbal–crystallized–knowledge aspects of adult abilities. A study of 167 adults ranging in age from 18 to 69 reasserts the importance of individual differences in completion test and cloze test performance in accounting for both measures of crystallized intelligence (Gc) and four scales of knowledge (biology, U.S. history, U.S. literature, and technology). The completion tests were found to account for all of the variance in Gc and knowledge that the cloze tests accounted for, and resulted in incremental predictive validity for both domains. In addition, completion and cloze tests were found to have a suppressor effect on the relationship between Gc and Age. We note that C. Spearman's [The nature of “Intelligence” and the principles of cognition. New York: MacMillan (1927).] assertion, namely that the completion test had higher correlations with intelligence than any other measure. Our results suggest that abstract reasoning may be far less useful in predicting learning and performance than the completion test is.     

Concurrent correlates and predictors of reading and spelling achievement in deaf and hearing school children

Seven- and eight-year-old deaf children and hearing children of equivalent reading age were presented with a number of tasks designed to assess reading, spelling, productive vocabulary, speechreading, phonological awareness, short-term memory, and nonverbal intelligence. The two groups were compared for similarities and differences in the levels of performance and in the predictors of literacy. Multiple regressions showed that both productive vocabulary and speechreading were significant predictors of reading for the deaf children after hearing loss and nonverbal intelligence had been accounted for. However, spelling ability was not associated with any of the other measures apart from reading. For hearing children, age was the main determinant of reading and spelling ability (due to selection criterion). Possible explanations for the role of speechreading and productive vocabulary in deaf children's reading and the differences between the correlates of literacy for deaf and hearing children are discussed.     

Spelling performance of English consonants among students whose first language is Arabic

The purpose of the present study was to examine the influence of some aspects of the Arabic phonological system on spelling English words. In Study 1, the spelling performance of Arabic students from grades four and six was compared with English students in cognate phoneme pairs which exist across both languages (/d/ and /t/), and pairs in which only one of the phonemes exists in Arabic (/b/ and /p/, /f/ and /v/) using a spelling test which contained words with the target phonemes. The findings showed that the Arabic participants performed similarly to the English participants on the phonemes /t/ and /d/, but they tended to spell the phonemes /b/, /p/, /f/, and /v/ using their cognate pairs more often than the English participants did. In Study 2, the spelling performance of Arabic students was compared across grades 4, 6, 8, and 10 for the same target phonemes. The analyses showed no difference between the Arabic participants in how often they confused the target phonemes with their cognate pairs across the different grade levels, except for the phonemes /p/ and /v/, for which the effect size was small. The findings of this study demonstrate the importance of phonology in spelling, as well as the influence of the first language on spelling in a second language. They also indicate that Arabic students continue to be dependent on phonological processes when spelling English words even as they grow older.     

Cognitive preconditions of early reading and spelling: a latent-variable approach with longitudinal data

The aim of the present study was to empirically disentangle the interdependencies of the impact of nonverbal intelligence, working memory capacities, and phonological processing skills on early reading decoding and spelling within a latent variable approach. In a sample of 127 children, these cognitive preconditions were assessed before the onset of formal education, whereas reading as well as spelling achievement was measured at the end of grade 1. The findings indicate that working memory does contribute to the prediction of early reading and spelling, and that this contribution outperforms that of general intelligence and phonological recoding from long-term memory during the early steps of reading and spelling acquisition. Moreover, the results show that phonological awareness mediates the effects of working memory capacities on early literacy outcomes. The role of working memory and phonological awareness as key cognitive preconditions of early reading and spelling are discussed.     

The impact of early metalinguistic competencies and memory capacity on reading and spelling in elementary school: Results of the Munich Longitudinal Study on the Genesis of Individual Competencies (LOGIC)

This paper reports on a longitudinal study dealing with the development of literacy in young children. A total of 163 children were first tested during their last year in kindergarten using a variety of tasks that tapped phonological processing, memory capacity, early literacy, and intelligence. Children’s word decoding, reading comprehension, and spelling skills were assessed in elementary school several years later. As a main result, all of the predictor domains had a significant impact on the acquisition of literacy in elementary school, although the contribution of each domain differed as a function of the criterion measure. An attempt to identify children-at-risk using a kindergarten screening test provided encouraging results. Nonetheless, it was shown that whereas group predictions of reading and spelling performance can be quite accurate, the individual prognosis of school problems is far from perfect.     

Plasticity in fluid intelligence of older adults: An individual latent growth curve modeling application

This article is concerned with modeling the individual latent growth curves of older adults on measures of fluid intelligence in a 2‐group cognitive intervention study (Baltes, Dittmann‐Kohli, & Kliegl, 1986). Second‐order polynomial growth curves reflecting initial test performance improvement followed by relative stability/drop are fitted to the recorded scores of each participant. Experimental subjects are found to exhibit mean ability growth outperforming that shown by untrained subjects. Both the control and experimental groups, however, demonstrate the same pattern of interrelationships among the individual ability intercepts, linear slopes, and quadratic bend parameters of the growth curves. The results suggest substantial amount of plasticity in fluid intelligence of older adults, and that elders may be capable of considerably improving their performance on repeatedly presented fluid measures by capitalizing on interrelationships between fluid intelligence subabilities.     

Structural extensions of a hierarchical view on human cognitive abilities

During the 1990s, research within the Individual Differences Unit at the University of Sydney was oriented towards expanding knowledge of poorly understood domains of human cognition. Using the theory of fluid and crystallized intelligence (Gf/Gc) served as the overarching framework. This research has led to an improved understanding of the nature of complexity and the role of working memory in Gf. Another outcome has been the charting of factors underlying of mental speed, tactile/kinesthetic performance, and olfactory memory. Recently, there has been exploration of the “borderline area” between abilities and personality. Our work on self-confidence and self-monitoring of cognitive performance has demonstrated excellent measurement properties of scores based on confidence ratings. We have also established a clear separation of a broad self-confidence factor from traditional intelligence and personality factors. Our research in these borderline areas has also explored the status of emotional intelligence. Results from several studies raise questions regarding the measurement of this construct.