1. The document discusses recent research on how executive functions fit within the Cattell-Horn-Carroll (CHC) theory of cognitive abilities and their relationship to general intelligence (g).
2. Studies have found that white matter integrity, processing speed (Gt), and executive functions are strongly related to general fluid intelligence (Gf) and that processing speed may mediate the relationship between white matter integrity and intelligence.
3. The Parietal-Frontal Integration Theory (P-FIT) model proposes that the frontal and parietal lobes are important for constructs like working memory, attention, and executive functions that relate to general intelligence.
14. Notice direction of arrows:
CHC abilities are considered to
be causal reflective variables
while g is considered to be a
formative variable that
“emerges”
18. The Parietal-Frontal Integration (P-FIT) Model of Intelligence
The frontal (esp., DLPFC) and
parietal lobes have been
repeatedly linked (via research)
to the cognitive constructs of
controlled attention, working
memory and executive
functions general intelligence
and higher level cognition
23. Bivariate Cholesky decomposition for additive genetic (A), shared environmental (C), and
nonshared environmental (E) contributions to executive function (EF) and measures of intelligence
24. Multivariate Cholesky decomposition for additive genetic (A), shared environmental (C), and nonshared
environmental (E) contributions to executive function (EF), measures of intelligence, and speed
28. R2 = 58.6 % of Gf
variance explained
White matterGtGf
30. Indicators of g-factor were
WAIS-III Gs tests (Symbol
Search, Digit Symbol), Gsm
tests (Digit Span-Backwards;
Let-Num. Seq),
Gf test (Matrix Reasoning),
and Gv test (Block Design).
Indicators of g-speed were
measures of reaction time
(Gt) – simple reaction time,
four-choice reaction time,
inspection time)
CHC test classifications not by
article authors but by Kevin
McGrew as per CHC theory
Three biomarkers of white matter integrity
31. •White matter integrity markers strongly correlated.
• Individuals with lower (higher) integrity also tend to have lower (higher) integrity in
all other white matter tracts.
• Results found that g-speed (cognitive information processing speed) factor fully
mediated the effects of the integrity of all three white matter biomarker tracts
(g-speedg of -.81)
• White matter integrity is to a substantial degree a brain-wide property.
• If an otherwise healthy individual shows structural deficits in one track, all other
tracts will likely also be affected to some degree.
• “White matter tracts constitute the neuroanatomical infrastructure for any brain
network model of cognitive performance, and tract integrity can be directly linked to
cognitive information processing speed and via this mediating path to general
intelligence.” (p.4)
32. These two (and other studies) suggest interesting white matter, Gs/Gt, g/Gf relations
Gt
Gs
Gf
g
Approximately 60%
of variance
explained