A new twist on old ideas: how sitting reorients crawlers

Abstract

Traditionally, crawling and sitting are considered distinct motor behaviors with different postures and functions. Ten- to 12-month-old infants were observed in the laboratory or in their homes while being coaxed to crawl continuously over long, straight walkways (Study 1; N = 20) and during spontaneous crawling during free play (Study 2; N = 20). In every context, infants stopped crawling to sit 3-6 times per minute. Transitions from crawling to sitting frequently turned infants’ bodies away from the direction of heading; subsequent transitions back to crawling were offset by as much as 180° from the original direction of heading. Apparently, body reorientations result from the biomechanics of transitioning between crawling and sitting. Findings indicate that sustained, linear crawling is likely an epiphenomenon of how gait is studied in standard paradigms. Postural transitions between crawling and sitting are ubiquitous and can represent a functional unit of action. These transitions and the accompanying body reorientations likely have cascading effects for infants’ exploration, visual perception, and spatial cognition.

Crawling and Walking Infants See the World Differently

“…The transition to sitting immediately transformed the visual world of crawlers; while sitting up, those same crawlers had a similar view of the room, people, and objects as did walkers. In fact, crawlers spontaneously stop crawling to sit up after only a few seconds of crawling in both standard crawling tasks and free play situations (Soska, Robinson, & Adolph, 2013), indicating that crawlers’ floor-centered view of the world is intermittent. Moreover, in everyday life, crawlers have additional postures available—standing or cruising upright—and they can view the world from a higher vantage point while being carried.…”

Bouts of steps: The organization of infant exploration

“…While crawling, infants primarily see the floor beneath their hands (Kretch et al, 2014). When crawlers sit up to look around, the whole room swoops into view, but the transition from quadruped to sitting turns their bodies 90°–180° away from the direction of original heading (Soska, Robinson, & Adolph, in press). When infants revert back to crawling, the transition in posture now turns their bodies in a completely different direction from what they were facing while sitting.…”

The Costs and Benefits of Development: The Transition From Crawling to Walking

“…When infants shift from crawling to sitting, they roll over one hip. This maneuver lands them in a legs out sitting position, but it also turns their bodies 90–180° away from the direction in which they were headed (Soska, Robinson, & Adolph, 2014). As a consequence, infants are no longer look ing where they were going originally.…”

“…The first-person viewpoint described earlier reveals that infants do not see objects across the room while they are crawling (Kretch et al, 2014). And when they shift from sitting (where they do see distant objects) to crawling (where they do not), the change in postures causes them to face in an entirely new direction (Soska et al, 2014). Perhaps as a consequence of differential visual access to objects, experienced 13-month-old crawlers crawl to retrieve distant objects on average only 4 times an hour, whereas novice 13-month-old walkers walk to distant objects 12 times an hour (Karasik, Tamis-LeMonda, & Adolph, 2011).…”