Sociology allows us to understand human behavior by using scientific methods to collect data and interpret it in ways that illuminate trends, norms, or deviations in human behavior. This can be done with experiments that mimic potential real life situations, and famously, some sociologists have conducted experiments on human behavior that have had far-reaching implications for sociology. One notable example would be the Milgram experiments that measured the influence of authority figures on subjects' willingness to inflict pain on other people. Subjects were told to inflict electric shocks in increments that slowly increased to other people (in reality those being "shocked" were actors and no harm was done to them). The subjects were merely given neutral orders to do so and were not forced or coerced. The findings indicated that many people only needed very gentle nudging to inflict pain on strangers.
One way in which the findings of such experiments can prove frustrating is the human tendency to disbelieve one's own capacity for cruelty or other negative behaviors. In other words, humans tend to think they are better behaved than they really are, and the findings of experiments such as Milgram's offer unsettling evidence to the contrary. The "big picture" takeaway from such findings is that when human atrocities occur and seem to be the result of one person's authority or ideology (such as Hitler and the Third Reich), we can extrapolate that, in fact, many or most human beings are capable of atrocious behavior under the right circumstances. Milgram's experiment bears this out, even if the results are disturbing and difficult to accept. By accepting the validity of such experiments (assuming they are done with the proper protocols and provide authentic results), we can learn a great deal about human behavior which can then in turn lead to a greater understanding of why we behave as we do.