Answer to Question 1
Answer: Research found that the long, hot summer was a true phenomenon. Riots were indeed more likely to occur on hot days than on cool ones. Other researchers have found that in a number of cities in the United Statesfrom Houston to Des Moinesthe hotter a given day, the greater the incidence of violent crime. This suggests that discomfort arising from heat can often contribute to violence and aggression. Other correlational research (horn-honking is more common in Phoenix drivers who don't have air-conditioning; batters are more likely to be hit by pitches on days when the temperature is above ninety degrees) has supported the phenomenon, as has experimental research.
Answer to Question 2
Answer: For the act to be considered hostile aggression, it would involve intentional harm for the purpose of hurting the other person directly. One reason may be that the first man was angry with the other person. Other reasons are possible. For the act to be considered instrumental aggression it would have to be intentional, but a means to an end. One reason a man might punch another person is to distract him from hurting someone else. Other explanations are possible. For the act to be considered nonaggressive, it would have to be unintentional. For instance, perhaps the punching man mistook the other person for someone else, or was flailing around because he isn't well and accidentally punched the other man.