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| 2. |
- Madison, Guy, 1961-, et al.
(författare)
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Correlations between intelligence and components of serial timing variability
- 2009
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Ingår i: Intelligence. - : Elsevier BV. - 0160-2896 .- 1873-7935. ; 37, s. 68-75
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Tidskriftsartikel (refereegranskat)abstract
- Psychometric intelligence correlates with reaction time in elementary cognitive tasks, as well as with performance in time discrimination and judgment tasks. It has remained unclear, however, to what extent these correlations are due to top–down mechanisms, such as attention, and bottom–up mechanisms, i.e. basic neural properties that influence both temporal accuracy and cognitive processes. Here, we assessed correlations between intelligence (Raven SPM Plus) and performance in isochronous serial interval production, a simple, automatic timing task where participants first make movements in synchrony with an isochronous sequence of sounds and then continue with self-paced production to produce a sequence of intervals with the same inter-onset interval (IOI). The target IOI varied across trials. A number of different measures of timing variability were considered, all negatively correlated with intelligence. Across all stimulus IOIs, local interval-to-interval variability correlated more strongly with intelligence than drift, i.e. gradual changes in response IOI. The strongest correlations with intelligence were found for IOIs between 400 and 900 ms, rather than above 1 s, which is typically considered a lower limit for cognitive timing. Furthermore, poor trials, i.e. trials arguably most affected by lapses in attention, did not predict intelligence better than the most accurate trials. We discuss these results in relation to the human timing literature, and argue that they support a bottom–up model of the relation between temporal variability of neural activity and intelligence.
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| 3. |
- Rodgers, Joseph, et al.
(författare)
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Identification of a flynn effect in the NLSY : Moving from the center to the boundaries
- 2007
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Ingår i: Intelligence. - : Elsevier. - 0160-2896 .- 1873-7935. ; 35:2, s. 187-196
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Tidskriftsartikel (refereegranskat)abstract
- The Flynn Effect [Flynn, J.R. (1984). The mean IQ of Americans: Massive gains 1932 to 1978. Psychological Bulletin 95, 29–51.] is an increase in IQ of around .33 points per year, observed in developed (and some developing) countries during the past century. It emerges from problem solving and other non-verbal components of IQ. The cause has been argued and theories proposed. Rodgers [Rodgers, J.L. (1998). A critique of the Flynn Effect: Massive IQ gains, methodological artifacts, or both? Intelligence 26, 337–356.] noted that the search for causes has preceded specification of the nature of the effect. Our study uses a national sample of U.S. children to test for the Flynn Effect in PIAT-Math, PIAT-Reading Recognition, PIAT-Reading Comprehension, Digit Span, and PPVT. An effect of the predicted magnitude was observed for PIAT-Math when maternal IQ was controlled. This finding in a large representative sample with thousands of variables supports more careful evaluation of the Flynn Effect, in demographic, geographic, environmental, and biological domains.
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| 4. |
- Rönnlund, Michael, et al.
(författare)
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The magnitude, generality, and determinants of Flynn effects on forms of declarative memory and visuospatial ability : Time-sequential analyses of data from a Swedish cohort study
- 2008
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Ingår i: Intelligence. - : Elsevier BV. - 0160-2896 .- 1873-7935. ; 36:3, s. 192-209
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Tidskriftsartikel (refereegranskat)abstract
- To estimate Flynn effects (FEs) on forms of declarative memory (episodic, semantic) and visuospatial ability (Block Design) time-sequential analyses of data for Swedish adult samples (35–80 years) assessed on either of four occasions (1989, 1994, 1999, 2004; n = 2995) were conducted. The results demonstrated cognitive gains across occasions, regardless of age, with no evidence of narrowing gender gaps. Across the entire range of birth cohorts (1909–1969) the estimated gain approached 1 SD unit. Over most cohorts the gains were largest for semantic memory, with a tendency of decelerating gains on the memory factors, but not on Block Design, across more recent cohorts (1954–1969). Together, differences in education, body height, and sibsize predicted virtually all (> 94%) of the time-related differences in cognitive performance. Whereas education emerged as the main factor, the need to consider changes multiple factors to account for FEs is underscored. Their relative influence likely depends on which constellations of ability factors and stages in ontogenetic and societal development are considered.
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| 5. |
- Tillman, Carin, et al.
(författare)
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Working memory components and intelligence in children
- 2008
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Ingår i: Intelligence. - : Elsevier BV. - 0160-2896 .- 1873-7935. ; 36:5, s. 394-402
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated, in children aged 6-13 years, how different components of the working memory (WM) system (short-term storage and executive processes), within both verbal and visuospatial domains, relate to fluid intelligence. We also examined the degree of domain-specificity of the WM components as well as the differentiation of storage and executive components. The short-term memory (STM) and WM tasks used allowed us to statistically separate the executive from the storage processes, enabling examination of separate processes in relation to intelligence. Our results demonstrated that all four WM components (verbal- and visuospatial short-term storage and verbal- and visuospatial executive processes) provided significant, independent contributions to intelligence, indicating that, in children, both storage and executive processes of the WM system are relevant to intelligence. Especially intriguing are our findings showing that verbal and visuospatial executive processes independently predicted intelligence, suggesting that, in children, the executive processes may rely on separate resources for the verbal and visuospatial domains.
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| 6. |
- Mouzon, Johanne, et al.
(författare)
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Fabrication of transparent yttria by HIP and the glass-encapsulation method
- 2009
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Ingår i: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 29:2, s. 311-316
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Tidskriftsartikel (refereegranskat)abstract
- This method consists of a combination of vacuum sintering at 1600 °C followed by hot isostatic pressing (HIP) at 1500 °C of a highly agglomerated commercial powder. The use of evacuated glass capsules to perform HIP treatment allowed samples that showed open porosity after vacuum sintering to be sintered to transparency. The sintering response of the investigated powder was studied by careful microstructural observations using scanning electron microscopy and optical microscopy both in reflection and transmission. The successful key of this method was to keep porosity intergranular during pre-sintering, so that it can be removed subsequently by HIP treatment. It was found that agglomerates of closely packed particles are helpful to reach that purpose, since they densify fully and leave only intergranular porosity. However, performing HIP treatment at 1625 °C was found to result in opaque samples. This was attributed to the diffusion of argon inside the capsule. Contamination at different steps of processing was also investigated by inductively coupled plasma mass spectrometry (ICP-MS).
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| 8. |
- Rönnlund, Michael, et al.
(författare)
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Adult life-span patterns in WAIS block design performance: Cross-sectional versus longitudinal age gradients and relations to demographic predictors.
- 2006
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Ingår i: Intelligence. - : Elsevier BV. - 0160-2896. ; 34:1, s. 63-78
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Tidskriftsartikel (refereegranskat)abstract
- Aging pattern in WAIS-R Block Design test (BDT) performance were examined cross-sectionally and longitudinally. One sample (35-80 years, n = 1000) was assessed in 1988-1990 and five years later (836 returned). An independent cohort-matched sample (n = 974) was included at Time 2 to estimate the magnitude of practice effects. Relations between BDT performance, gender, and education were also examined. The cross-sectional analyses indicated a gradual age-related deterioration from 35 to 55, even when minor practice effects were adjusted for. Decline was apparent for the older cohorts, regardless of estimation method. Education-adjusted cross-sectional differences showed a similar pattern. A minor age- and time-invariant gender difference favoring males was observed. Education predicted some time-related change, such as higher education was associated with lesser decline. Collectively, the results demonstrate the nedd to control for cohort and retest effects in cross-sectional and longitudinal studies, and reveal interesting relations between BDT performance and demographic variables.
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