Transformations in the Couplings Among Intellectual Abilities and Constituent Cognitive Processes Across the Life Span

Abstract

ABSTRACT-Two-component theories of intellectual development over the life span postulate that fluid abilities develop earlier during child development and decline earlier during aging than crystallized abilities do, and that fluid abilities support or constrain the acquisition and expression of crystallized abilities. Thus, maturation and senescence compress the structure of intelligence by imposing age-specific constraints upon its constituent processes. Hence, the couplings among different intellectual abilities and cognitive processes are expected to be strong in childhood and old age. Findings from a populationbased study of 291 individuals aged 6 to 89 years support these predictions. Furthermore, processing robustness, a frequently overlooked aspect of processing, predicted fluid intelligence beyond processing speed in old age but not in childhood, suggesting that the causes of more compressed functional organization of intelligence differ between maturation and senescence. Research on developmental changes in functional brain circuitry may profit from explicitly recognizing transformations in the organization of intellectual abilities and their underlying cognitive processes across the life span.Spearman (1904) discovered the ubiquitous positive intercorrelations among intelligence tests. Since his work, most researchers in the field of intelligence have viewed the structure of intelligence as static (see Carroll, 1993, andSternberg, 1994, for overviews), overlooking possible developmental transformations in the organization of intellectual abilities and their underlying information processing and neurobiological mechanisms.

Literacy effects on language and vision: Emergent effects from an amodal shared resource (ASR) computational model

“…General processing speed (Kail & Salthouse, 1994;Salthouse, 1996) has been shown to correlate with performance on a wide range of cognitive tasks (Kail & Salthouse, 1994;Li et al, 2004;Salthouse, 2005), and has been proposed to be the mechanism of increased cognitive efficiency as a consequence of literacy training. For instance, Stoodley and Stein (2006) showed that literacy skills correlated with a general increase in speed of performance on a pure motor task.…”

EEG gamma-band synchronization in visual coding from childhood to old age: Evidence from evoked power and inter-trial phase locking

“…Recent behavioral and physiological evidence suggests that interactions between maturation and learning from childhood to adulthood lead to increasing cortical differentiation and integration (Johnson, 2001;Nelson and Luciana, 2001;Thatcher, 1992) that is accompanied by more refined intellectual ability structures (Garrett, 1946;Li et al, 2004). Senescent changes from adulthood to old age, on the other hand, result in dedifferentiation and reduced cortical specialization of functional circuitry (Park et al, 2004; see also Reuter-Lorenz and Lustig, 2005 for review) that are accompanied by dedifferentiated cognitive and sensorimotor functions (Baltes and Linden- berger, 1997;Li et al, 2004). However, surprisingly little is known about lifespan changes in neuronal mechanisms that code sensory events during visual perception.…”

“…In the present study, we opted for a task that (a) is relatively easy to perform for all age groups, and (b) allows for the parametric variation of input (i.e., size) in order to observe neuronal processes of interest (i.e., temporal synchronization in early visual processing) without the confounding factor of lifespan differences in task proficiency. By using a simple choice-reaction task, we sought to minimize the contamination of observed age differences in neuronal mechanisms of visual coding with concomitant age differences in cognitive proficiency such as attention, working memory, and executive functions (Li et al, 2004;Rugg and Morcom, 2005).…”

Associative and strategic components of episodic memory: A life-span dissociation.

“…The functioning of episodic memory undergoes profound and continuous changes across the life span (Baltes, Lindenberger, & Staudinger, 2006;Graf & Ohta, 2002;Li et al, 2004). From childhood to young adulthood, pronounced monotonic and steep improvements in episodic memory are observed (Ceci, Lea, & Howe, 1980;Schneider & Pressley, 1997).…”