There are seven sensory systems in the human body. Each system is a complex interaction of perception and experience that can be dysfunctional in some cases of autism. Specific behaviors can help us identify which system is lacking or over stimulated. The five senses are taste, touch, sight, hearing and smell. The sixth sensory system is the vestibular system, and the seventh is the proprioceptive system. The vestibular system involves how our bodies process movement. Sight is closely tied to this system. The proprioceptive system involves the body's natural way of adjusting to its environment. This system involves fine motor activities like buttoning a shirt and coordinated activities like walking down steps.