Final answer:
A child playing on a swing is displaying behavior indicative of seeking vestibular sensory input, which is related to balance and spatial orientation.
Step-by-step explanation:
The child who immediately jumps on the platform swing and rocks back and forth is seeking vestibular sensory input. The vestibular system is part of the inner ear and is responsible for providing our brain with information about motion, head position, and spatial orientation; it is also involved in motor functions that allow us to keep our balance, stabilize our head and body during movement, and maintain posture. When a child seeks movements like rocking, swinging, or spinning, it typically indicates a need for vestibular input. This behavior does not reflect tactile input (which would be related to touch), auditory aversion (which would be related to sound sensitivity), or proprioception (which is the sense of body position, movement, and balance, not directly stimulated by the act of swinging).