Line bisection as a neural marker of approach motivation.

Approach motivation has been reliably associated with relative left prefrontal brain activity as measured with electroencephalography (EEG). Motivation researchers have increasingly used the line bisection task, a behavioral measure of relative cerebral asymmetry, as a neural index of approach motivation-related processes. Despite its wide adoption, however, the line bisection task has not been confirmed as a valid measure of the precise pattern of activity linked to approach motivation. In two studies, we demonstrate that line bisection bias is specifically related to baseline, approach-related, prefrontal EEG alpha asymmetry (Study 1) and is heightened by the same situational factors that heighten the same approach-related prefrontal EEG alpha asymmetry (Study 2). Results support the line bisection task as an efficient and unobtrusive behavioral neuroscience measure of approach motivation.