Two Articles Accepted in Developmental Science
The Perception, Action, and Development Lab published two articles in the journal Developmental Science. The first article, Within-day variations in infant body position predict caregiver speech input, was authored by doctoral student Hailey Rousey, former staff members Maximilian Tang and Sahrai Garcia, and John Franchak. The second article, Infants’ daily routines shape opportunities for perceptual-motor exploration, was authored by John Franchak, Juelle Ford (former undergraduate student), Prof. Caitlin Fausey (University of Oregon), and doctoral student Aylin Luna. Open-access PDFs are available on the publications page.
Paper Abstract: Within-day variations in infant body position predict caregiver speech input
Infants’ time spent in different body positions varies substantially within a day: lying supine on their backs, crawling or playing while prone on their bellies, sitting on the floor or in seating devices, standing or walking upright on two feet, and held by an adult. Infants may spend long periods in one position, such as sitting in a highchair, followed by periods of switching positions (e.g., prone and upright), such as during play. Speech input has been linked with infants’ placement and motor development (Karasik et al., 2014; Malachowski et al., 2023). Here, we extend past work to ask whether adults speak more frequently depending on infants’ time spent in different body positions throughout the day. We gathered home recordings from 64 infants in two age groups, 4-7 months and 11-14 months, using movement sensors to measure body position and a LENA® audio recorder to estimate adult word count. Data were analyzed in 10-minute bins throughout the day to determine whether within-day differences in infants’ time spent in each position were associated with the frequency of adult’s speech. Indeed, increased time spent supine and prone predicted fewer adult words, whereas increased time sitting and held predicted increases in word count. Upright was age dependent, with more time spent upright predicting an increase in word count for younger infants, but a decrease for older infants. These findings reveal the importance of considering infants’ body position in understanding speech input and subsequent language development.
Paper Abstract: Infants’ daily routines shape opportunities for perceptual-motor exploration
How infants spend time in everyday life is an important source of day-to-day, infant-to-infant, and age-related variability in development. Here, we measured the frequency of macro-level activity categories—playing, eating and drinking, napping, going on errands, bathing and dressing, watching media, book reading, and being comforted—in infants aged 4-7 and 10-13 months recruited from across the United States (55% female assigned at birth; 40% male assigned at birth; 5% unknown). Unlike past work that used retrospective estimates, we used an ecological momentary assessment sampling method to obtain direct reports of activities from infants’ caregivers via text-message surveys. The resulting data illustrate that play is the most frequent activity within the first year, accounting for half of infants’ waking time. Other frequent activities, such as mealtimes and errands, contribute significantly to how infants spend their time. Older infants spend more time playing and eating/drinking and less time napping and being comforted compared with younger infants. Importantly, different macro-level activities facilitate and constrain what infants do from moment to moment, such as hold objects, sit, and stand, suggesting that the composition of infants’ daily routines shapes opportunities for perceptual-motor learning.
