Who is afraid of pirates? An experiment on the deterrence of innovation by imitation

In the policy debate, intellectual property is often justified by what seems to be a straightforward argument: if innovators are not protected against others appropriating their ideas, incentives for innovation are suboptimally low. Now, in most industries and for most potential users, appropriating a foreign innovation is itself an investment decision fraught with cost and risk. Nonetheless, standard theory predicts too little innovation. Arguably the problem is exacerbated by the sensitivity of innovators to fairness; imitators do get a free lunch, after all.