A developmental psychologist at the University of California, Riverside, has completed a study that is the first to measure how often infants spend time in different body positions over the first year of life

The study, published in the journal  Infancy, aims to understand how the physical context of infants' everyday experiences-in particular, how much time they spend in different body positions-changes throughout the first year and how these changes are predicted by infants' developing motor skills.

"I was surprised to find that 3-month-olds are held almost half of their waking days said John Franchak, an assistant teacher of psychology, who performed the study. "Twelve-month-olds are held much less frequently and spend most of their time on the ground How often infants play, crawl, walk, or sit changes how they interact with objects and changes, too, the physical way in which they interact with other people. "

Specifically, Franchak found that sitting, upright, and prone (belly towards the ground regardless of contact with the ground) accounted for less than 7 percent of the 3-month-old infant's day. By 12 months, these positions accounted for 62% of the infant's day.

The cross-sectional study sought to understand what 12-month-old learns and how this learning differs from that of, say, to the 3-month-old infant, based on their everyday experiences. Toward that end, the study tested separate groups of 3-month-olds, 6-month-olds, 9-month- old, and babies that were a year old. It used data acquired for 95 babies from across the United States.

The study used to acquire this data: the infants' caregivers were sent text messages five times a day for a week to inquire about what the baby was doing at that moment. The caregivers electronically reported infant body thereafter in brief one-minute surveys.

They also reported infants' location-if the infants were on the floor or up on a raised surface-and onset of sitting, crawling, and walking. The study is the first to use this method, momentary assessment, to measure infants' behaviors.

"We have plenty of data on what babies do in the lab, where we measure their development by doing some assigned task," Franchak said. "What we do not know is what drives that development, what happens in the days, hours, and minutes they are at home, where the number of things that let them learn until this study, we did not know how often babies sit, crawl, and stand in everyday life, outside the lab."

"The momentary ecological assessment the study used offers a better sense of infants' current lives versus a slice of life in the lab and gives a more realistic distribution of their different types of body positions and experiences. Understanding these differences allows us to build better theories about how to infants develop and learn from the world. "

Acquiring new motor skills

Franchak explained that body positions change dramatically over the first year of life, and much of that change results from infants acquiring new motor skills. Typically, babies begin to sit around six months of age, crawl at around 8months, stand around 11 months, and walk when they are a year old.

Item is important to study infant body position, he said, because changes in how babies interact with the world change their opportunities for learning. Learning to sit is linked with better object perception. Learning to walk is lined with improved language ability

"The number of infants spends in different positions shapes their visual and manual activity-impacting perceptual, cognitive, and social development-and reflects opportunities to practice and develop motor skills, "Franchak said." For example, infants rarely see faces while playing on the ground in sitting, upright, and prone positions, but she faces more often when held or sitting off the ground as in a high chair.

"Further, infants who can sit independently at six months spend more time sitting in daily life. Este allows them to manipulate objects more frequently and receive nearly as much opportunity to experience the richer visual-manual exploration of objects than prone or supine infants, "he added." Learning to walk changes social interactions with caregivers and predicts improvement in infants' spatial cognition. "

Franchak cautioned that caregivers play an important role in influencing the study's results. The study's youngest infants are entirely dependent on caregivers to change their body position. For older infants, choosing to sit or stand is often an option only if their caregivers provide the opportunity.

"I can not say enough about how much caregivers are doing in determining what their positions are in their babies ," he said. "Caregivers act in response to how they perceive their children." Caregivers and their babies then negotiate constantly on how best to proceed thereafter.