Murder Is in Our Blood
On May 11, 2005, a jury convicted Pete Terrazas of murdering his next-door neighbor, Miguel Ruiz. Terrazas had been dating Ruiz's housekeeper, Maria Santillana, whom he deeply loved. When she abruptly broke off the relationship, Terrazas concluded that she had begun an affair with Ruiz. Terrazas loaded his .410-gauge shotgun, went over to his neighbor's driveway, blasted Ruiz in the back and then took deadly aim at the man's chest. Pete Terrazas had never before been violent. Nor had Scott Peterson before he killed his wife, Laci. Nor had Clara Harris before she ran over her adulterous husband with her Mercedes in a hotel parking lot in Houston.
My own interest in studying murder began when I witnessed a close friend, a highly accomplished academic, fly into a murderous rage and come frighteningly close to killing his wife. This raised a disturbing question: Could "normal" people become killers? In seven years of research on murderers, I discovered that an astonishing 91% of men and 84% of women in five different cultures have had at least one vivid fantasy of committing murder.
As my research continued, I became convinced that we all have the capacity to become murderers. There's a compelling reason why. Over the long sweep of deep time, killing has conferred such powerful advantages in the ruthless game of reproductive competition that natural selection has forged in all of us minds designed to murder. Murderer's genes prevailed over those of their unfortunate victims, and we are their descendants.
Our minds are designed to kill. It's part of human nature.
Previous theories about why people kill typically invoke single factors -- the murderer is pathological, or the violent product of poverty, or warped by child abuse, poor parenting or exposure to media violence. But I concluded that every one of these theories is wrong.
The unfortunate fact is that killing has proved to be a disturbingly effective solution to an array of adaptive problems in the unforgiving evolutionary games of survival and reproductive competition: preventing injury, rape or death; protecting one's children; eliminating a crucial antagonist; acquiring a rival's resources; securing sexual access to a competitor's mate; preventing an interloper from appropriating one's own mate; and many others. The logic of evolutionary struggle is all about reproductive competition. Those strategies that lead to greater reproductive success are selected for, over eons of evolution, and come to characterize our species.
