Is the act of sneezing contagious?

Probably not. Sneezing is a reflex originating in the nerves (sensory) innervating the nasal lining surface. The reflex then ascends to the brain which then causes the muscles of the chest and the diaphragm to contract. This enables us to eliminate the irritant that started the original irritation. This complex reflex arc starting in the nose is highly unlikely contagious. If a virus started it, it could be.