Clinical assessment of movement and posture guides the decision-making process in designing interventions for infants and children with movement disorders. Clinical reasoning is influenced by the therapist's understanding of developmental processes. The views of development grounded in perception-action, dynamic systems, and neuronal group selection theories are well recognized in current literature and supported by a large body of research. Based on the available evidence, intervention must be task-specific, repetitive, and highly salient to the child. Furthermore, it must honor spontaneous exploration and active problem-solving, enhance the child's ability to perceive environmental affordances, and target optimal variability and adaptability of movement and posture. However, a neuromaturational approach to developmental assessment and intervention that relies on "teaching" motor milestones and emphasizes the importance of correcting movement patterns in infants and children developing atypically is still prevalent in the clinic. This perspective paper will: (1) examine evidence in support of a paradigm shift from neuromaturational views toward bringing the concepts of grounded cognition, variability, complexity, and adaptability to the forefront of clinical reasoning; and (2) introduce the Perception-Action Approach as a method of assessment and intervention that may serve as an agent of such a shift by augmenting knowledge translation for the clinician.