By contrast, the following week, when a crazed man with an assault weapon opened fire, killing 20 little children at Newtown, Conn.'s Sandy Hook Elementary School, there were no passive bystanders concerned about their own safety. The faculty of this school acted as courageous individuals without concerted effort, let alone reference to the headlines and despairing scholarship to save lives. Courageous teachers such as Vicki Soto, Anne-Marie Murphy, Rachel D'Avino and Lauren Rousseau, as well as principal Dawn Hochsprung and school psychologist Mary Sherlach gave their lives by putting themselves in front of the armed intruder. The devoted educators did not consider their own well-being for a moment before they acted. What is the explanation for such contrasting human conduct? Is it the callousness of New York's big-city life versus the more intimate small-town values of idyllic Newtown, 80 miles away? Was it the identification with the victim -- perhaps ethnic prejudice against Han, a Korean, versus compassion for innocent, vulnerable children? Was it that Han was a stranger to those on the platform while the teachers of Sandy Hook had a bond with the children? Perhaps it was all of those factors -- but perhaps it was more. New York Times columnist Joe Nocera recently drew upon some pioneering research to conclude: "Sadly, the science says we're more likely to do nothing than to respond." His sources were two 20-something psychologists, Bibb Latane and John Darley, who a half century ago conducted intensive studies of the bystander effect to understand why people do not help others in distress in emergency situations -- even when there are others nearby to assist them. Their interest was catalyzed after the public outrage over the apathetic neighborhood response to the 1964 murder of 28-year-old Kitty Genovese in the Kew Gardens section of Queens. At least a dozen, and some initial reports suggested 38, neighbors heard her calls for help as an assailant stabbed her. As one neighbor was memorably quoted by the New York Times: "I didn't want to get involved."