Drawing on records of behaviours discrepant with the A, B, and C classifications, a fourth classification was added by Ainsworth's colleague Mary Main. In the Strange Situation, the attachment system is expected to be activated by the departure and return of the caregiver. If the behaviour of the infant does not appear to the observer to be coordinated in a smooth way across episodes to achieve either proximity or some relative proximity with the caregiver, then it is considered 'disorganised' as it indicates a disruption or flooding of the attachment system (e.g. by fear). Infant behaviours in the Strange Situation Protocol coded as disorganised/disoriented include overt displays of fear; contradictory behaviours or affects occurring simultaneously or sequentially; stereotypic, asymmetric, misdirected or jerky movements; or freezing and apparent dissociation. Lyons-Ruth has urged, however, that it should be wider 'recognized that 52% of disorganized infants continue to approach the caregiver, seek comfort, and cease their distress without clear ambivalent or avoidant behavior.'