It was Bart Simpson who told his sister, "If you don't watch the violence, you'll never get desensitized to it!" (The Simpsons: Colonel Homer). Was he right and should we follow his implied advice?
The issue of desensitization is a tricky one. The idea is that the more we are exposed to certain things, the less sensitive we are to them. This is not the place for a lengthy survey of psychological studies, but for the purposes of this book we can grant the popular opinion that this is the case. Desensitization therapy has been successful in curing many cases of phobias and other hypersensitive issues. Desensitization does seem to occur, at various levels and for various amounts of time, with repeated exposure to particular elements, including when those elements are found in movies. The question, though, is whether we should be concerned about this phenomenon.
First, it should be noted that desensitization is largely an emotional issue. That is, it is not with the will or the intellect that desensitization necessarily occurs. Thus, it is one's emotional reaction that is considered when studying sensitivity to certain elements, not what is thought or willed concerning them. Is emotional response a serious concern for the Christian? Sin is an action of the will / intellect, not the emotional reaction of the body (this does not mean that emotional reactions cannot serve as indicators of the intellect / will e.g., Jer.6:15; Amos 6:1; Matt. 21:32; Phil. 1:7; 1 Tim. 5:11). For example, I am not responsible for my reactive feelings if I see a beautiful woman walking by - but if I set my mind to think about her sexually, then I have committed sinful lust.
Second, the Bible does not command that we feel a certain degree of emotion to be morally upright, only that we agree with what is right. This distinction is missed by many who confuse one's feelings with one's thoughts. For example, The New Bible Dictionary cautions that it is possible for man's conscience-the faculty by which he apprehends the moral demands of God and which causes him pain when he falls short of those demands-to be inadequately disciplined, to become weakened and defiled (1 Cor. 8:7-12; cf. Titus 1:15), and to grow seared and ultimately insensible (1 Tim. 4:2).
However, 1 Corinthians 8:7-12 is actually referring to someone whose conscience is hypersensitive, not desensitized, and 1 Timothy 4:2 is referring to unbelievers, the impure to whom all things are impure. If an emotional desensitization is sinful, other verses will have to be marshaled to show that this is the case. What we think and do are at issue in the Bible's descriptions of righteousness and sin, not how we feel. So simply having less of an emotional reaction may not be as bad as it is often assumed to be.
Third, in many cases strong emotional reactions are indicators of immaturity. Children react with far more emotion than is acceptable in adult society, but we would think it a tragedy were the emotional reactions of a child not under better control by adulthood. Maturity actually seems to require a certain degree of "desensitization." Another indication that desensitization is not always bad is that in some cases it is not only accepted, but expected, that certain individuals be desensitized to things that others are not. Not only those in law enforcement but doctors, soldiers, ranchers, and others could not function if their reaction to criminal behavior, injury, nudity, violence, or death were the same as others. Yet we do not consider them less morally upright than anyone else for such desensitization.
Finally, in classical theology the majority position has always been that God Himself is without emotion. That is, He is said to be impassible ("without passions"). While this attribute of God is not undisputed, the fact is that orthodox believers have affirmed God's "non-sensitization" for centuries without fearing any subsequent loss of His goodness.
So desensitization might only be considered a problem if it affects the will or intellect (and some studies indicate that it can). If it comes about that viewing violence or sexual acts, listening to profanity, or anything else should cause us to become less caring, act less uprightly, or go in any other immoral direction, then we should cease consumption of such things. This extends beyond mere style elements-it would include being influenced by positive portrayals of immorality (the politically motivated inclusion of socially enjoyable and attractive, yet sinful, characters in many TV sitcoms might be a case in point).