Ideology has to be present before the act for it to be used as an excuse for the behavior. If ideology wasn’t there before the behavior, then you can’t make the behavior fit one. This is important because it tells you that the act was governed by impulses and the reptilian brain, rather than the use of the frontal lobe, which is involved in planning and forecasting. This difference can tell you something about the neurology of the individual, and tell you about the kind of person you are dealing with.
Via Sakis Koukouvis