| Description |
In response to the growing need to understand individual differences in executive functioning (EF) among non-neurologic populations, this study examined two competing theoretical models of EF among healthy, neurologically-intact individuals: the prefrontal convexity model and the hemispheric asymmetry model. A total of 315 neurologically healthy individuals (M = 20.8 years; 50% female) completed two phases of the study. In the first phase (i.e., Model Identification), latent profile analysis was applied to variables measuring the abilities to form, switch, and maintain mental sets under conditions designed to tax the left or right hemisphere (i.e., a modified switching task). In the second phase (i.e., Model Validation), latent clusters from the first phase were compared on a separate EF task (i.e., Attention Network Test; ANT). The Model Identification phase yielded a three-profile solution consistent with the hemispheric asymmetry model. Profile 1 (N=203) was characterized by average EF performances. Profile 2 (N=43) revealed a set maintenance weakness under nonverbal conditions. Profile 3 (N=38) demonstrated a global weakness in cognitive flexibility and a specific weakness on tasks administered under verbal conditions. The Model Validation phase confirmed group/cluster differences (F(4,554) = 5.938, p<.001). Individual differences in EF follow a hemispheric asymmetry model of EF, with approximately 15% of neurologically healthy individuals exhibiting weaknesses in set maintenance and nonverbal processing, and 13% exhibiting weaknesses in set formation/switching and verbal processing. |
