Table 1.

Operational definitions of general (nonsocial) and social behaviors observed in these experiments

General (nonsocial)
 LocomotionWalks, runs, climbs, or jumps
 ManipulationHandles, chews, licks, moves, or smells objects or cage parts
 PassiveInactive, stays in one location
 Self-directedEngages in self-directed behaviors, i.e., self-grooms, hugs head, self-grabs and bites, presses face with hands, self-holds, closes fists, self-clutches, sexually self-stimulates, prone, or head on chest
 ApproachInitiates social contact; moves body or head toward the conspecific
 IsolationSits alone
 Social contactAny physical contact between the subject and conspecific.
 Grooming-related behaviors conspecificSubject grooms the conspecific, subject presents for grooming, subject is groomed by the conspecific
  • Note that our analysis ethogram also included aggression, mounting, play, withdrawal, motor stereotypies, and vocalizations, but these were either completely absent or observed at very low rates so were not formally analyzed further.