Table 2.

Engagement and Disengagement Behavioral Cues[13]

Behavior	Definition
Subtle Engagement
Facial brightening	infant moves mouth or cheeks as if smiling
Hands open	fingers apart from palms but not stiff
Potent Engagement
Facial gaze/focus	infant looks towards mother's face without making direct eye contact
Mutual gaze	infant makes direct eye contact with mother
Cyclic extremity movement	infant moves arms and/or legs in a slow, fluid manner
Relaxation posture	awake infant (behavioral state =1) lies still with extremities relaxed
Subtle Disengagement
Eyes clinched	eyes narrow or shut tightly
Gaze aversion	infant breaks eye contact with mother or looks purposefully away
Finger splay	infant opens hands fully and stiffens fingers
Struggling movements	infant jerks extremities or tries to avoid mother's contact by moving away
Finger extension	infant extends and stiffens a single finger
Hunger posture	infant lies with arms drawn up to sides, fists clenched beside shoulders
Potent Disengagement
Crying	infant wails loudly
Whining	infant makes soft cries or whimpers
Fussing	infant makes distressed sounds quieter than crying
Cry face	infant wrinkles face, clenches eyes as if crying but without making sound
Halt hand	infant stiffens hand as with finger splay but in addition extends it towards the mother as if trying to block something
Maximum lateral gaze aversion	infant turns head to the side to avoid mother's face/gaze