Related Experiment Video
Updated: Jan 13, 2026
A Within-subjects Experimental Protocol to Assess the Effects of Social Input on Infant EEG
Published on: May 3, 2017
Within-Day Variations in Infant Body Position Predict Caregiver Speech Input
Hailey N Rousey1, Maximilian Tang1, Sahrai Garcia1
1University of California, Riverside, California, USA.
Insights
Adults speak more to infants when they are sitting or held, but less when infants are lying on their backs (supine) or bellies (prone). Infant body position influences speech input, impacting language development.
Area of Science:
- Developmental Psychology
- Infant Motor Development
- Speech and Language Acquisition
Background:
- Infants spend varying amounts of time in different body positions daily, including supine, prone, sitting, upright, and held.
- Previous research suggests a link between speech input and infant motor development.
- The relationship between specific infant body positions and the quantity of adult speech input remains underexplored.
Purpose of the Study:
- To investigate whether adults' speech frequency is associated with infants' time spent in various body positions.
- To examine age-related differences in the association between infant body position and adult speech input.
Main Methods:
- Utilized home recordings from 64 infants (4-7 months and 11-14 months) with movement sensors to track body position.
- Employed a LENA audio recorder to quantify adult word count.
- Analyzed data in 10-minute intervals to correlate infant body position with adult speech frequency.
Main Results:
- Increased time spent in supine and prone positions was associated with fewer adult words.
- Increased time spent sitting and being held predicted higher adult word counts.
- The association between upright position and word count varied by age: positive for younger infants, negative for older infants.
Conclusions:
- Infant body position is a significant factor influencing the amount of speech input received.
- Findings highlight the importance of considering body position in studies of early language development.
- Results partially support theories linking motor skill acquisition with language development.
Abstract:
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. 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-min 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. SUMMARY: Tested how infants' body positions (supine, prone, sitting, upright, and held) relate to adults' speech input in naturalistic home settings. Machine-learning algorithms predicted infants' body positions from motion sensors embedded in custom leggings. Adults spoke relatively more when holding infants and while infants sat, but less frequently when infants were prone and supine. Results provide partial support for theorized links between motor skill acquisition and language development.
Related Concept Videos
01:28Relationship with Parents: Attachment
01:30Socioemotional Development during Infancy
Primary Temperament Types
01:24Facial Feedback Hypothesis
01:22Language Development
The critical period for language acquisition suggests that the ability to acquire language is at its peak early in life. As people age, this proficiency decreases. Language development begins very...
00:55Parental Care
01:20Attachment