color and behavior having a common cause (a pleiotropic gene effect), it would be predicted that where one sibling was blue eyed and one brown eyed, that the blue eyed one was more likely to be behaviorally inhibited.
(color and behavior; having; a common cause) (the blue eyed one; was; more likely to be behaviorally inhibited) (the blue eyed one; to be; behaviorally inhibited)
color and behavior the blue eyed one the blue eyed one
having was to be
a common cause
more likely to be behaviorally inhibited
behaviorally inhibited