Final answer:
The study on Aché infants in Paraguay showed that cultural practices of carrying infants delayed walking until 23-25 months, later than Western standards, but by age 9 their motor skills surpass those of U.S. children.
Step-by-step explanation:
The research study conducted on the Aché tribe and the raising of infants and the impact on motor skills found interesting correlations between child-rearing practices and developmental milestones. The Aché of Eastern Paraguay engage in foraging behaviors that influence how infants are cared for in their early life stages. Mothers predominately carry their children, rarely putting them down, to keep them safe in the forest. This protective measure results in Aché children starting to walk on average between 23-25 months old, which is later than the average in Western cultures where walking typically begins around 12 months old. However, as they grow older and gain more freedom of movement, Aché children develop motor skills that surpass those of U.S. children of the same age, including the ability to climb tall trees and navigate through forests with machetes, highlighting that while the timing of developmental milestones like walking can vary across cultures, the ability to perform complex motor functions is present in all societies.