On the night of February 26, 2012, Trayvon Martin, a 17-year-old African American high school student, was shot by a neighbourhood watch volunteer, George Zimmerman, in a predominantly White neighbourhood. Zimmerman grew suspicious of the boy dressed in a hoodie and pursued Martin. A physical altercation ended with Zimmerman fatally shooting Martin. Zimmerman claimed that he acted in defence. Martin was unarmed, and after his death, there was a nationwide outcry. A Florida jury found Zimmerman not guilty of second degree murder nor of manslaughter. George Zimmerman was a resident in the housing complex, not on the job, when the shooting occurred.

There have also been tragic situations with deadly consequences in which police officers have shot innocent civilians. In 2019, Atatiana Jefferson’s neighbour used a non-emergency line to call the police because Jefferson’s front door was open in the late hours of the night. The police arrived and an officer went to the back of the yard. Jefferson, not knowing that the police had been called, reached into her purse and got out her legally owned gun. The officer perceived a threat and fired upon Jefferson, killing her. Her 8-year-old nephew witnessed the incident, as he was playing video games with his aunt. Why did each of these nights end so tragically for those involved? What dynamics contributed to the outcomes? How can these deaths be prevented?

Social psychologists examine how the presence of others impacts how a person behaves and reacts, whether that person is an athlete playing a game, a police officer on the job, or a worshiper attending a religious service. Social psychologists believe that a person’s behaviour is influenced by who else is present in a given situation and the composition of social groups.