This condition is synesthesia and it occurs from increased communication between sensory regions and is involuntary, automatic, and stable over time. While synesthesia can occur in response to drugs, sensory deprivation, or brain damage, research has largely focused on heritable variants comprising roughly 4% of the general population. Synesthesia isn’t a disease or disorder. It won’t harm your health, and it doesn’t mean you’re mentally ill. Some studies suggest people who have it may do better on memory and intelligence tests than those who don’t. And while it may seem easy to make up, there’s proof that it’s a real condition. Some synesthetes hear, smell, taste or feel pain in color. And many synesthetes experience more than one form of the condition.