"Executive functions" cannot be distinguished from general intelligence: two variations on a single theme within a symphony of latent variance.
The empirical foundation of executive control function (ECF) remains controversial. We have employed structural equation models (SEM) to explicitly distinguish domain-specific variance in executive function (EF) performance from memory (MEM) and shared cognitive performance variance, i.e., Spearman's "g." EF does not survive adjustment for both MEM and g in a well fitting model of data obtained from non-demented older persons (N = 193). Instead, the variance in putative EF measures is attributable only to g, and related to functional status only through a fraction of that construct (i.e., "d"). d is a homolog of the latent variable δ, which we have previously associated specifically with the Default Mode Network (DMN). These findings undermine the validity of EF and its putative association with the frontal lobe. ECF may have no existence independent of general intelligence, and no functionally salient association with the frontal lobe outside of that structure's contribution to the DMN.
Department of Psychiatry, The University of Texas Health Science Center, San Antonio San Antonio, TX, USA ; Department of Medicine, The University of Texas Health Science Center, San Antonio San Antonio, TX, USA ; Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio San Antonio, TX, USA ; The South Texas Veterans' Health System Audie L. Murphy Division, Geriatric Research Education and Clinical Center San Antonio, TX, USA.
Donald R
DR
Royall
Department of Family and Community Medicine, The University of Texas Health Science Center, San Antonio San Antonio, TX, USA.
Raymond F
RF
Palmer
aging; cognition; dementia; executive function; functional status; g; intelligence