7.11: Systems Approach

An increasingly popular view in developmental psychology that has been used to understand how developmental changes emerge is the Dynamic Systems Approach (DSA) (e.g., Thelen and Smith, 1994; Lewis, 2011; Molenaar et al., 2014; Blumberg et al., 2017). The hallmark of the DSA is its emphasis on all components of the system including genes, environment and the task. The DSA has provided lasting changes in understanding development in a variety of fields but started with the work of Thelen in motor development. Systems approach suggests that interacting motor, perception and cognition changes occur as a child develops. Consider that in the infancy the developmental requirements are to overcome gravity (from the prenatal stages where all movements were possible until space constricted them). Once posture is stable, the infant can move and it gives them new vantage points for perception and exploration.

As posture control changes, arms and hands become available for reaching, holding and manipulating objects so that the infant can develop more knowledge about textures, sizes and 3-dimensionality.

Posture also influences perception because the infant develops newly changed vantage points as they go from the prone to the sitting to the standing.

On the other hand, posture is also influenced by perception, for example when walls sway, we move our muscles to counteract that swaying and maintain balance. Infants do that also, but not as smoothly as adults do.

Stepping has been believed to be a reflex that appears at 2 months, later disappears, and then walking develops even later. But the claim is that if the infant gets upright practice, the stepping reflex never would disappear. In Western culture infants spend a lot of time supine, they do kick in the air – which is the same as the stepping movement – but they develop more fat than muscle in their legs making it difficult to walk. So, in contrast to the reflex proponents who claim that changes in cortical control drive the changes in motor coordination, DSA proponents claim that changes in the body (driven by culture and environment) explain the development of walking.

Infants use various strategies for locomotion. Motivated by their caregiver, for example, and the initial position they are put in (tummy down for example), they try out various ways to move including log rolling, pivoting, turning etc to look at and get to where they want to. When they have to get off steep places they try out different things like sliding or backing down (which is harder because they have to coordinate backward movements and have no visual feedback). They also use (or choose not to use) handrails when trying to maintain balance in creative ways.

Walking is very much influenced by practice (massage and exercise of the kind in African and Caribbean cultures). Infants learn the balance issues – first walk with feet wider apart, more time standing, less time with one foot in the air, etc. With practice in those cultures, children learn to walk and run much faster than in Western cultures. In East Africa women, and in Nepal both genders learn to walk with much larger than own body weight loads with reduced energetic cost.

The visual cliff apparatus has been used in original studies of depth perception but infants learn after the first encounter that there is glass at that drop off.  So now many studies have been done to test locomotion with deep drop offs as well. What is found is that infants don’t generalize the perceptual information from one locomotive skill to another. For example, even though they know what to do while crawling, they will keep falling for weeks while walking in the same situation.

So, locomotion is not hardwired or reflexive, but rather extremely plastic and responsive to caregiving practices. Locomotion is also creative. Every infant discovers unique solutions for locomotion, given their own particular environment.

Manual control

Infants reach with both hands and feet. Their control improves over time and with practice. They try to judge where a moving object will be and flap out at it. However, more specific hand control doesn’t develop till later of course. Once infants can hold objects, they flap their arms to make a sound with hard objects and move soft ones across surfaces. In the beginning, they only bring objects up to their face and mouth them, but later move it from hand to hand and palpate it and so on. At first arm and hand movements are random and exploratory, and they become more goal directed as infants grow.

Facial muscle coordination is really marvelous because newborns need to suck, swallow and breathe once they are out of the amniotic fluid, and need to suck for sustenance! Because solid foods require more than just lateral movement of the jaw and also experience with food of different consistency and texture, there is real danger of choking.

Facial expressions in infancy are similar to adult ones like wrinkling of nose and furrowed brows to noxious environment. Many parts of the face are used to show expressions, perhaps because those are so important for social interaction. So even infants with severe developmental or structural problems are still able to produce recognizable smiles, cries and interest expressions.

Coordinating looking movements have been calculated and studied by researchers. Infants and toddlers tend to engage more in opportunistic looking so in this sense arrangement of the environment also influences what they are more likely to see. Researchers have studied where infants look, and how they track objects and how that becomes smoother with infant age and practice. Infants are also closer to the floor so they tend to look more at it while they are smaller.

“The developmental systems perspective encourages researchers also to consider a larger context that includes the physical and social/cultural environment and to view motor behaviors as potentially both cause and consequence of developmental change in other psychological domains”

References:

Adoph, K.E. & Franchak, J.M. (2016). The development of motor behavior. WIREs Cognitive Science, 8, 1-18. doi:101002/wcs.1430

Golenia, L., Schoemaker, M. M., Otten, E., Mouton, L. J., & Bongers, R. M. (2017).What the Dynamic Systems Approach Can Offer for Understanding Development: An Example of Mid-childhood Reaching. Frontiers in Psychology, 8. doi: 10.3389/fpsyg.2017.01774