"Does your baby watch TV?": The associations between at-home TV watching and laboratory challenge cortisol are different for young infants and their mothers.

This longitudinal study examined associations between at-home TV watching and the biological stress response (cortisol) during a laboratory infant cognitive challenge task in 240 3- and 5-month infants and their mothers. Cortisol levels were lower in mothers of 5-month-old infants whose infants were exposed to TV at home, compared to mothers of infants that were not TV-exposed. Cortisol patterns were different across three laboratory sampling intervals for 3-month-old infants as a function of TV watching, revealing a sharp increase in laboratory cortisol only for infants who were exposed to TV at home.