You may think this division is artificial, and it is. Groups influence individuals; individuals influence groups. A specific discipline called social psychology studies this gray area in between individuals and groups. Social psychology is sometimes found as a discipline of psychology, and sometimes in sociology. While this shouldn't make a big difference, psychology and sociology have different background literatures for their students to learn, and use different research methods. As a result, psychological social psychologists and sociological social psychologists may rarely talk to each other or recognize each others' work. It's a shame because our work should inform each others'. My training, by the way, was in social psychology, from the psychology side.

Q. What does each side of the brain control?

A. The visible, commonly known part of your brain is called the cerebral cortex. This is split into two halves, called cerebral hemispheres. These hemispheres are connected to each other via a bridge of fibers called the corpus callosum. We know that each hemisphere of the cerebral cortex is specialized for some functions. On the broadest level, the hemispheres are "contralaterally specialized," meaning that the left hemisphere controls the right side of the body, and the right hemisphere controls the left side. For the most part, the functions on the left side of the brain parallel the functions on the right, but there are a few exceptions. The most obvious one is language: it's only on one side of the brain. We have also discovered through brain scanning studies that logic and analytical thinking tends to be centered in the left hemisphere of the brain, while emotions and artistic sensibilities tend to be centered on the right side. As it happens, unless you have had brain surgery or some form of brain damage, it hardly matters: both sides of the brain communicate with each other constantly, and both sides are active most of the time.

Q. What side of the brain controls the reaction actions, such as a goalie stopping a shot?

A. Short answer: the cerebellum. But that's not very educational.

Motor control is a pretty complex topic, and I don't pretend to have more than a simple understanding of it. But the impulse to move starts in the motor cortex, a strip of brain tissue at the back of the frontal lobe. It sends signals down toward the spinal cord. Signals are also sent through a complex system of nuclei (dense collections of neurons) in the middle and of the brain called the basal ganglia. These are a feedback and control system that helps initiate the actual movement, modify it, and stop it, so that you move exactly the way you want to, not too hard or too soft. (Consider a robot picking up an egg. Without these feedback and control systems, the robot is more likely to crush or smash the egg than pick it up safely. You need to be able to feel the very slight resistance from the eggshell to know you've gripped it, stop squeezing immediately, but keep a firm grip so that you're actually holding it, etc.) The modified signals pass down the spinal cord to the proper vertebral level, where motor impulses are sent out from the spinal cord to the actual muscles that do the work.

Meanwhile, the cerebellum, that deeply corrugated structure at the rear bottom of your brain is also modifying signals. Apparently, well-practiced motor behaviors are stored here, so that they can be executed smoothly without you needing to think about them. In fact, these behaviors don't need much attention: a really good goalie may be able to block some shots without even being aware that one was coming, because the cerebellum is responding to information that has not yet reached awareness.

Q. Why do people and animals lash out irrationally under certain situations?

A. Well, what are those situations? Odds are, the person or animal in question is irritated, or better still, frustrated. When we are in these unpleasant states of mind, we are experiencing arousal. Arousal involves adrenaline and all sorts of systemic responses bring us into the state commonly called "fight or flight." When we are aroused, we don't like to take time to think; we usually act on the first response that comes to mind. This is called the "dominant response," because it's more likely to occur than other responses. Aggression is a common dominant response. You could argue aggression is built into most animals, ourselves included; you could argue it is easily learned because in childhood it often gets you what you want. Our aggressive behaviors are inhibited and tamed by parenting and by society, which frowns on violence. But when we're aroused, inhibitions tend to lose strength, and the aggressive dominant response results.

Knowing this, you can understand why a happy, aroused crowd can become violent: the arousal reduces inhibitions against violence, and the right spark can set off a riot. It also explains why you might not want to tell somebody you wrecked their car when they're all pumped up by watching a great football game—even if their team won.

But we're even more likely to lash out when we're both aroused and unhappy. When we're angry, we want somebody to blame it on. Any target will do, even one that has nothing to do with the original problem. It takes a great deal of effort to cool down and realize that this person is not the cause of your anger.

The best way to avoid committing this irrational aggression is to learn to calm down and relax. Venting your anger by pounding a wall, imagining doing harm to somebody, or working out only increases your arousal, which can actually keep your anger hot, rather than cool it off.

Submit your own question: email me at dushayr@morrisville.edu

See earlier "Ask Dr. Bob" pages:

August 25
September 1
September 15
October 20
November 17
January 26

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