Herd Behavior and Other Curiosities.

In this series of posts, I will look at crowd or herd behavior. Sometimes this is referred to as collective intelligence. Let’s say that you are at a Green Bay Packers game – in December. Suddenly Brett Favre throws a pass and the receiver breaks free and starts running for the goal line. Everyone jumps up in excitement and cheers him on. This is one of those adrenaline-pump moments (I suppose the perceived threat is that he may get caught from behind and deny us our touchdown) and we feel our heart racing. As Biologists, we also know that blood is shunted away from the PFC to the motor and ocular cortices and we have an irresistible urge to do something. That’s why we jump up and down and spill our beer. Oh yeah, I forgot to mention the beer.

The receiver makes a furious dash and, just as he’s being tackled, crosses the goal line. Pandemonium erupts. You look at your buddies and, suddenly, in the middle of December, you all strip off your clothes and start dancing and singing. In the middle of December. On the “Frozen Tundra” of Lambeau Field. Why? Later, your wife or girlfriend, who has witnessed the whole sordid affair on television, also asks you “WHY?” And you say, “I don’t know. It felt like the thing to do at the moment.” And you really don’t know and can’t explain why you did it.

You all know what’s coming now, don’t you? Well, before I let you answer this, I’ll add a few more details. You and your buddies are under 25 years of age and started drinking beers some two to three hours before the game began. OK, now you’re ready. Since you’re under age 25 - 30, modern neuroscience suggests that your Pre-Frontal Cortex has yet to fully develop. You are therefore more likely to be impulsive. The alcohol has further disinhibited your behavior. Because you’re in a group, there is strong social pressure to fit in and go along with the group. Finally, under the adrenaline rush, what blood is able to make it to your pitifully few remaining functioning PFC neurons is shunted away. You now have no restraints on your behavior. This is, in essence, what happens in “crowd-think” or mass hysteria. You never see a solitary individual strip off unless he’s very drunk or very disturbed.

Now, I know that there are psychological models for crowd think or collective intelligence. My purpose is not to discuss those models, but to explain what is happening, biologically, when a crowd sees someone on a ledge. The identification with the potential suicide victim puts us into threat mode. And when some disinhibited or sociopathic individual shouts, “Jump!” you all take up the call. And when asked afterwards why you shouted, “Jump!” you too say, “I don’t know why I did it.” And you are being truthful because this was not a conscious, well thought-out decision. Your PFC did not participate. And had there not been that trigger, you probably would never have done so. Or if someone had started praying for the victim, you might very well have joined in with that prayer. The essential fact is that we humans can do strange things without thinking, under the right circumstances.