IKIDS Study Timeline
4-5 Months of Age
Mothers bring their infant to our research lab when they are 4-5 months of age to repeat some measurements done at birth and to complete some new cognitive tests. The data collected are:
- Stool Sample: Mothers collect a sample of their child's stool at home and bring it to the research lab when they come for their child's assessment. Analyses are run to examine the association between prenatal exposure to endocrine disrupting chemicals (EDCs) and the gut microbiota, as well as changes in the microbiota between birth and 5 months.
- Sexually dimorphic indices: Physical measurements that differentiate boys and girls are repeated at this age and the associations between prenatal exposure to EDCs and these physical measurements is analyzed.
- Child's cognition: Two cognitive tasks are administered to assess the relationship between prenatal exposure to EDCs and cognitive function at this age. During both tasks, infants sit in their caregiver's lap and watch videos on a computer screen. Their eye movements are tracked by a hidden observer and an eye tracker. One task involves mental rotation and the other requires they reason about the behavior and properties of an object. The tasks are described next.
This task was developed by Renee Baillargeon and colleagues. In the original task, infants watch, on alternate trials, a possible and an impossible event on a puppet stage. In these events an object is placed against a wall and released. In the possible event, the object is placed a few inches above the platform but, surprisingly, it remains stable. Baillargeon found that, at this age, girls but not boys, are surprised by the impossible event as suggested by their looking longer at the impossible than at the possible event. Boys tend to look equally low at the two events, suggesting that they do not find any of the events surprising.
We have developed videotaped versions of Baillargeon's live events, and we will examine whethere prenatal exposure to EDCs alters the pattern of sex differences in infants' responses to these events.
IMPOSSIBLE EVENT POSSIBLE EVENT