Old age captchas are good. Infact, Google's new "Click here to confirm you're not a robot" is an excellent option.
Are there any other ways?
Not very effective alone, but can be used together with other strategies is to check the amount of time it took to complete the form and mouse movements
I wouldn't say it's a boolean decision, but it could be added in a score system where logic mouse movements adds to the human score.
Arun Yokesh
Developer @ Appoets
Use Google's Recaptcha I'm not a Robot here which more secure that you expect and i think what you expecting is this -> google's invisible recaptcha which is coming soon to the market