Answer:gaining informed consent from participants.
Explanation: As Aaron is going to conduct the experiment on obtaining the response from the audience for an violent image, he is taking already informed consent from them. He is letting everyone know about the experiment subject so that no objectionable participation will be present.
As the violent image can be critical and harsh for some people, Aaron wants to make sure that everyone has the hint about the experiment . In this way, people sensitive towards the violent scenarios can withdraw theirselves from experiment and others can prepare theirselves for the conduct.
