Final answer:
Hypnosis increases activity in the frontal lobe attention systems and supports the role of dissociation, where attention to sensory input is blocked and consciousness is altered.
Step-by-step explanation:
Brain scans have shown that hypnosis increases activity in the frontal lobe attention systems. Although hypnosis does not block sensory input, it appears to block our attention to it, lending support to the role of dissociation in hypnosis. Dissociation in the context of hypnosis refers to a state of consciousness where an individual's attention is so narrowly focused that they become less aware of external stimuli, much like being engrossed in a task to the point of obliviousness to one's surroundings. This is evidenced by Ernest Hilgard's research where participants' arms were placed in ice water and, although they reported not feeling pain due to being under hypnosis, they did react by pressing a button, which demonstrates a split in awareness.