Answer to Question 1
Answer: Reactance theory posits that when people feel their freedom is threatened, an unpleasant state of reactance is aroused. One way people can reduce this unpleasant state is to engage in the prohibited behavior. Therefore, a message that is too strong can backfire and cause individuals to become more likely to engage in those behaviors. Thus, one tactic is to use subtle messages that do not make individuals feel as though their freedoms are being threatened.
Answer to Question 2
Answer: Attitude inoculation involves exposing people to small doses of arguments counter to their initial attitudes, like a vaccination against disease. In this case, you would expose your brother to weak versions of arguments that he might hear later from his peers (e.g., condoms look stupid, or condoms ruin the sensation of sex), and encourage him to refute those arguments (I can enjoy the feeling of sex a lot more if I don't have to worry about illnesses or getting you pregnant). In addition, you might give him some practice role-playing and show him ways to combat these pressures. This should make him more immune to more powerful persuasive messages later.
Scientists (group photo)
Students working in a group
Scientists should use a variety of media to present the message
Average Annual Growth Rates of Population by Country Group
Monophyletic vs. paraphyletic group
Victims of police-reported intimate partner violence 2017 to 2018