Within ACL 2.8, attention is captured by: a vertical sense of balance, big visual cues below the knees and external objects that pass within their arms reach. The process of evaluating the information in their hand probably takes at least 5 seconds. If they compare their current experience with past experiences, their lack of ability to speak makes it hard to guess what they are thinking. What we observe is a lack of ability to make a choice between maintaining a strong grasp and releasing their grip. The lack of comparisons and choice support the concept that automatic actions do not reach the cortex, at least initially. The sense of balance probably engages the cerebellum, but reaching out and grasping may include some activation of the cerebellum.
What they learn from using their hands is rigid. Exercises are followed by rote and they will hold onto very few objects.