[header] How to tell if you have synesthesia [title] Realize that synesthesia is relatively rare, but likely under-diagnosed. [step] Synesthesia is considered a rare neurological condition that affects the senses, but it's likely that many people who have it are either undiagnosed or assume that other perceive the world just like them. It is unknown how many people have synesthesia. 
[title] Know that not everyone with synesthesia experiences it physically. [step] If you actually see colors in the air, smell, hear, or feel things, you have projected synesthesia.