What is the difference between aiding and abettor culpability under the natural and probable consequences doctrine for a nontarget, or unintended, offense committed in the course of committing a target crime?

Aider and abettor culpability under the natural and probable consequences doctrine for a nontarget, or unintended, offense committed in the course of committing a target offense has a different theoretical underpinning than aiding and abetting a target crime. Aider and abettor culpability for the target offense is based upon the intent of the aider and abettor to assist the direct perpetrator commit the target offense. By its very nature, aider and abettor culpability under the natural and probable consequences doctrine is not premised upon the intention of the aider and abettor to commit the nontarget offense because the nontarget offense was not intended at all. It imposes vicarious liability for any offense committed by the direct perpetrator that is a natural and probable consequence of the target offense. (People v. Garrison (1989) 47 Cal.3d 746, 778 [accomplice liability is vicarious].) Because the nontarget offense is unintended, the mens rea of the aider and abettor with respect to that offense is irrelevant and culpability is imposed simply because a reasonable person could have foreseen the commission of the nontarget crime. It follows that the aider and abettor will always be "equally guilty" with the direct perpetrator of an unintended crime that is the natural and probable consequence of the intended crime.