I don't want to hear why CAPTCHA's suck for user experience, I already know the pros and cons.
I am using CAPTCHA on a website that has an older audience that may not be familiar with what CAPTCHA's are and what their purpose is, unlike in this discussion. With that in mind, what is the best text to label the CAPTCHA with? The goal is to inform users as quickly as possible what to do without confusing them.
Here are some common examples:
"Are you human?" "Please enter the following text in the box below:" "Security Check:"
I'm not sure if these examples have sufficient explanation, but if you put too much explanation it may be overwhelming... see this example: