Canadian researchers have added a subtle but potentially significant nuance to the old warning, “Watch the hands.”
A study at the University of Alberta has found that the length of a man’s index finger relative to his ring finger can be a predictor of his predisposition for physical aggression. The shorter the index finger is compared to the ring finger, the higher his potential for physical violence.
This sounds like lockup lore. Even the study’s co-author, Dr. Peter Hurd, thought the finger-aggression link was “a pile of hooey” until he studied the data. But Dr. Bill Lewinski, executive director of the Force Science Research Center at Minnesota State University-Mankato, says the finding has a firm foundation in human science.
“This is associated with the level of testosterone a fetus is exposed to when it is developing in the womb,” Lewinski told Force Science News. “Testosterone influences not only how the aggression-related centers of the brain develop but can also affect the evolution of fingers that is taking place at the same time. The more testosterone, the greater the impact.”
The effect tends to negatively influence the maturing fetus’s capacity for empathy and compassion, as well, Lewinski says. However, the study found no correlation between finger lengths and nonphysical forms of aggression, such as mere verbal abuse, anger or hostility. Nor does the finger-length finding appear to apply to women.
Because of personal variables within the general results of the study, Hurd cautions against drawing hard conclusions about specific people. But Lewinski points out that you should be watching the hands of subjects you deal with as an officer-safety consideration anyway and this is one among other potential indicators of trouble that you can take note of.
“More than anything,” Hurd says of his study in a report published in HealthDay News, “I think the findings reinforce that a large part of our personalities and our traits are determined while we’re still in the womb.”
Hurd’s research group plans to continue its investigation of physical aggression by studying the relative finger lengths of hockey players to see if there is a correlation with the penalty minutes they rack up in a given season
More details of his recent findings appear in the March issue of the journal Biological Psychology.