Following is a rather sizeable chunk of text from How God Changes Your Brain. It is taken from the section on religious fundamentalism and its (detrimental) affect on the brain. Not just evangelical fundamentalism...but any group that nurtures an us vs them mentality with angry rhetoric and hate speech. Sermons about hell, and sinners, homosexuals and Muslims, fornicators and liberals seem to be a mainstay of evangelical fundamentalists in this country. "Allah be praised!! Death to the infidels" is the Islamic version of hate speech. Exposure to this kind of crap can actually damage your brain....not to mention it incites violence and spreads more hate and fear far and wide.
If you allow anger and fear to dominate, you will lose the neurological ability to think logically and act compassionately toward others. In fact, it is nearly impossible to find peace and serenity if your mind is preoccupied by negative, anxious, or hateful thoughts.
Excessive anger or fear can permanently disrupt many structures and functions in both your body and your brain. These destructive emotions interfere with memory storage and cognitive accuracy, which, in turn, will disrupt our ability to properly evaluate and respond to social situations. Anger makes people indiscriminately punitive, blameful, pessimistic, and unilaterally careless in their logic and reasoning skills. Furthermore, anger encourages your brain to defend your beliefs—be they right or wrong—and when this happens, you’ll be more likely to feel prejudice toward others. You’ll inaccurately perceive anger in other people’s faces, and this will increase your own distrust and fear. It’s an insidious process that feeds on itself, and it can influence your behavior for very long periods of time. Eventually, it will even damage important structures in your brain.
The Neurological problem of fundamentalism does not lie in the firm adherence to a specific set of beliefs. Rather, the problem arises when individuals use their religion to justify angry feelings toward others. Specifically, expressing or listening to angry thoughts can disturb the normal neural functioning of many parts of the brain. In fact, just reading emotionally evocative words stimulates the amygdala and hippocampus in ways that resemble the encoding of traumatic memories.
When you listen to angry speech--in a congregation or political forum--specific parts of your brain begin to mirror the angry content of the speaker. All you have to do is see a harsh, angry or contemptuous face in a picture, and the same neural reaction will be triggered because the circuits involving the human amygdala are particularly responsive to the emotional expression on other people's faces. And the stronger the expression, the stronger your emotional reaction will be.
Unfortunately, as far as the brain is concerned, negative speech has a stronger effect than positive speech. Negative remarks and memories are more strongly encoded in the brain, and they are the most difficult memories to eradicate. In fact, simply being around negative people will make you more prejudiced, because listening to negative opinions can easily undermine your positive opinions about virtually anything.
In essence our brains are designed to mimic the emotional expressions of others. Not only does this allow us to feel what others feel, but it causes what is known as emotional contagion, a universal neurological process whereby subjective feelings are transferred to other people and spread through social groups. So how fast does it take the brain to react to another persons emotion? When you see an angry expression, it takes less than one second for your brain to respond with fear.
I want to bring up an important but often overlooked point. What you choose to meditate upon, or pray for, can do more than change your brain. You can damage it, especially if you choose to focus on something that makes you frightened or angry. In Psychology this is called rumination and it is clearly hazardous to your health. In a Stanford brain scan study, people who focused on negative aspects of themselves, or on a negative interpretation of life had increased activity in their amygdala. This generated waves of fear, releasing a torrent of destructive neurochemicals into the brain.
Interesting how the Bible tells us
Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things.Phillippians 4:8 KJV
or as The Message renders it:
Summing it all up, friends, I'd say you'll do best by filling your minds and meditating on things true, noble, reputable, authentic, compelling, gracious--the best, not the worst; the beautiful, not the ugly; things to praise, not things to curse.