Poster #163 - Object exploration during the sitting transition: A study of infants at heightened risk for ASD

• In Event: 2-055 - Poster Session 06
  In Poster Session: PS 06 Section - Perceptual, Sensory, Motor

Integrative Statement

Object exploration, through which infants learn about the surrounding world, is supported by postural development, especially the acquisition of independent sitting. Sitting enhances accessibility to objects and increases opportunities to explore (e.g., Soska & Adolph, 2014). Infants at heightened risk (HR) for developing Autism Spectrum Disorder (ASD) by virtue of having an affected older sibling exhibit delays in independent sitting (e.g., Nickel et al., 2013). The question then arises as to whether delayed sitting exerts a cascading effect on object exploration in HR infants. The present study was designed to explore whether object exploration changes during the first month of independent sitting in HR infants compared to infants with no family history of ASD (Low Risk; LR).
Infants (19 HR and 23 LR, age range: 5–8.5 months) completed the Object Exploration Task (OET) adapted from a previous study (Ruff, 1984) at the onset of independent sitting and one month thereafter. The onset of independent sitting was identified when an infant could withstand 30 seconds of sitting without any support (including arm support). The OET included a total of 12 trials with objects that varied in color, texture, and shape. During each trial, the infant sat on a caregiver’s lap at a tabletop and explored one object at a time for 30 seconds. Total durations of manual contact (touching and grasping) and coordinated looking (simultaneous touching and looking at an object) were coded from videos. Object mouthing was also identified and categorized as active (lips, teeth, or tongue engaged with object) or passive (lips in static contact with object).
Results indicated that, on average, HR infants began to sit nearly three weeks later than their LR peers. Infants in both groups spent significantly more time touching and grasping objects following sit onset (see Figure 1), but durations of coordinated looking were generally unchanged. In addition, while HR infants showed little change in the relative durations of active vs. passive mouthing across the month following sit onset, for LR infants, the duration of active mouthing increased sharply (p = 0.002) while the duration of passive mouthing decreased, though not significantly (see Figure 2).
These findings strongly support the idea that the onset of sitting is accompanied by changes in infants’ approach to object exploration. For the most part, these changes occur for both HR and LR infants, albeit later for the later-sitting HR infants. The one exception, relative lack of increase in active vs. passive mouthing for HR infants, is consistent with a variety of studies reporting generally lower levels of active initiation of behavior in HR infants (e.g., Nickel et al., 2014). Future research with HR infants should address the question of possible downstream developmental effects of delays in sit onset and concomitant object exploration on other acquisitions (e.g., lexical growth).

Authors

• Erin Jarvis, University of Pittsburgh
  Presenting Author

• Kelsey West, University of Pittsburgh
  Non-Presenting Author

• Jana M Iverson, University of Pittsburgh
  Non-Presenting Author