[This article was originally published in December, 2006]

As parents of a 15 16-year-old, Greta and I are very interested in what causes people to behave aggressively. We know a lot about specific causes of aggression -- violent media, testosterone, guns, and personal insults can all lead to aggressive behavior in certain circumstances. But kids and others exposed to one or more of these things don't necessarily become violent. Sometimes it seems that just the presence of his sister in the room can cause Jim to act more aggressively than he would otherwise.

That's one reason we were intrigued by a recent study by Jennifer Klinesmith, Tim Kasser, and Francis t. McAndrew -- it attempts to suss out the combined effects of guns and testosterone on aggression. The other reason is that it involves spiking other people's drinks with Frank's Red Hot Sauce. What could be more fun than that?

Previous studies examining the effect of the hormone testosterone and aggression have had mixed results. While other studies have shown a link between gun handling and aggression Klinesmith's team noticed that no study had explored the link between guns, testosterone, and aggression.

They told 30 male college student volunteers they'd be participating in a study on taste sensitivity and attention to detail. Each participant provided a sample of saliva prior to the study (this would later be used to determine testosterone levels), then spent fifteen minutes performing one of two tasks. Fifteen of the men worked with the game "Mouse Trap"; their task was to write a set of instructions on how to assemble and disassemble it. The other 15 men had the same task, but the object of their description was a pellet gun that was an exact size / weight replica of a Desert Eagle automatic handgun.

After the description task, participants provided another saliva sample, and then were given a cup filled with 85 grams (about 1/3 cup) of water and one drop of Frank's Red Hot Sauce. This, they were told, was the "taste sensitivity" portion of the study. They were asked to rate the taste of the sample, which (they were told) had been prepared by the previous research participant. Next, they were given a clean glass filled with 85 grams of water, and a bottle of Frank's Red Hot Sauce, which they were told to use to prepare a sample for the next participant.

Of course, the real purpose of the study was to see if handling the weapon would increase testosterone levels, and if participants were more aggressive after handling the weapon compared to the child's game. Here are the results:

The results are dramatic: Testosterone levels increased significantly after handling the gun, while they didn't increase at all after a similar task with the game. And the gun-handlers put more than three times as much hot sauce in the water as the game players: over 13 grams, in just an 85-gram container of water, creating a solution that was over 15 percent hot sauce.

Klinesmith's team argues that this study shows that simply handling a gun causes men to be more aggressive. Further analysis of the data shows that the aggression is mediated by testosterone levels. In other words, if the effect of testosterone levels is removed from the hot sauce aggression data, then the correlation between weapon-handling and aggression is significantly lower. This suggests that the increased testosterone levels are a key to increased aggression.

The team notes that there are some important limitations to the study. Participants were told they were acting anonymously, and there was no fear of retribution. Perhaps if they had to confront their "victims," their behavior would have been different. Also, it's possible that frequent gun-handlers wouldn't show the same increased aggression after handling a gun -- the high testosterone levels and aggression might have been more a result of the novelty of the situation than of the particular impact of a weapon.

Needless to say, if you have a gun in the house, you'd better keep your hot sauce locked up! Or is it the other way around?