Coding of Outcomes
Theoretical variables
Of primary interest in this study was the effect of exercise on cognitive processes identified by the four theoretical positions (speed, visuospatial, controlled processing, and executive control). Therefore, each task (or condition within a task) was categorized as to whether each of the four theoretical positions would predict that the task would be differentially sensitive to improvements in aerobic fitness. A task was coded as 1 for a given theoretical position if it should show differential improvement ac- cording to that position, and given a 0 otherwise.
Effect sizes were coded as belonging to the speed category if the task represented a measure of low-level neurological functioning, such as simple reaction time (e.g., the speed with which one can make a manual response to a flash of light) or finger-tapping speed. Likewise, effect sizes were coded under the visuospatial category if the task tapped the participants’ ability to transform or remember visual and spatial information (e.g., viewing three line drawings and then repli- cating them from memory as in the Benton Visual Retention Task). Ef- fects coded to represent controlled processes were from tasks that require, at least initially, some cognitive control (e.g., pressing one key when presented with the letter C, but pressing a different key for the letter M, as in a choice reaction time task), but do not have those char-