Abstract
Human behavior is known to be idiosyncratic, yet research in neuroscience typically assumes a universal brain-behavior relationship. Here we test this assumption by estimating the level of idiosyncrasy in individual brain-behavior maps obtained using human neuroimaging. We first show that task-based activation maps are both stable within an individual and similar across people. Critically, although behavior-based activation maps are also stable within an individual, they strongly diverge across people. A computational model that jointly generates brain activity and behavior explains these results and reveals that within-person factors have much larger effect than group factors in determining behavior-based activations. These findings demonstrate that unlike task-based activity that is mostly similar among people, the relation between brain activity and behavioral outcomes is largely idiosyncratic. Thus, contrary to popular assumptions, group-level behavior-based maps reveal relatively little about each individual.
Competing Interest Statement
The authors have declared no competing interest.
