Figure 3.

Four-month follow-up visit time-line. The ~60 min protocol consists of: (1) consent, (2) mother-infant play, (3) stranger-infant play (4) diaper change, (4) Still-Face paradigm, (5) parental questionnaires. Cortisol (c; "red circle") is measured at 4 times: consent, ~15 min after mother-infant play (before diaper change), 15 min after still-face (~min 49), and 30 min after still-face (~min 64). Abbreviations: c "red circle", cortisol; HR, heart rate; HRV, heart rate variability; M/I, mother-infant; S/I, stranger/infant.