Think about cavemen. Odds are that the image that comes up for you is of someone with a sloped forehead, and maybe a rather small head. A sloped forehead suggests that the area of your brain, specifically the left prefrontal lobe, that controls aggression is under-developed. The left prefrontal lobe also plays a role in keeping you feeling happy, so if there's not much there, you are likely to feel less than joyful and all the more quick to anger.
As to the small head, new evidence suggests that the amygdala, which is from the earlier, even reptilian stage of brain development, varies in size. People such as those with borderline personality disorders who tend toward emotional chaos with volatility and rages—earning them the nickname of Drama Queen—have a relatively small inner brain piece called the amygdala. (See p.1289 of Neurobiology of Mental Illness, edited by Dennis S. Charney and Eric J. Nestler.) Somehow this apparently smaller size seems to correlate with less sophisticated or nuanced readings of the world.
The amygdala of highly emotional people therefore gives false positives. That is, it screams "Danger!" to mobilize people to fight or flight, when the actual threat does not merit such a strong response. A hyper-active amygdala sees danger where there is none and overrates the degree to which what lies ahead is in fact a genuine threat.
If you are a caveman, quick responses are likely to save you from beasts who would like to enjoy eating you for dinner. In our contemporary world however most dangers do not need immediate reflexive responses. Better to be able to think than to rush into immediate aggressive action.
The bottom line: Beware if you have a tendency to react like a caveman.
The good news is that when you feel yourself beginning to become angry, if you leave the situation immediately odds are good that you will be okay. Leave the situation for a few minutes to give your brain time for your thinking ability, which travels on a slower neurological system than the caveman parts of your brain, to kick into gear and start quietly collecting and processing data.
Again, when in doubt, just get out.
Return to the situation once you have calmed down so that thinking can lead you to a safe plan of action.
Better safe than sorry. And better savvy than caveman.
Denver psychologist Susan Heitler, Ph.D. specializes in teaching couples the skills for marriage success. Her interactive onine marriage program at PowerOfTwoMarriage.com and her books for therapists and for couples aim to make the world a safer, more mature, less caveman-like place.