The science of the bystander effect
On the morning of a seemingly ordinary spring day in 1964, twenty-eight year old bartender Kitty Genovese drove back to her apartment after a night shift. After parking her car in the lot next to her abode, Kitty noticed a looming figure at the very back of the lot. She turned around and began to walk in a different direction, but the man quickly followed suit. Kitty screamed for help; responsively, her apartment neighbors turned on their lights, went to their windows, and watched as the man stabbed her. One of her neighbours yelled down at the attacker, “Let that girl alone!” As a result of the commotion, Kitty’s attacker fled the scene. However, as soon as the lights were turned off and the windows were drawn shut, the man returned and stabbed Kitty again. The scene repeated itself, and Kitty was stabbed a third time. Finally, the police were called approximately fifty minutes after the first sighting of the attacker—or rather, murderer, because Kitty died en route to the hospital. It was later reported that there were thirty-eight bystanders to Kitty’s murder. When the bystanders were questioned about why they did not intervene or call the police earlier, there were some interesting replies, such as “I didn’t want to get involved,” “Frankly, we were afraid,” and “I was tired. I went back to bed.”
So, naturally, the question that springs to mind is a simple one: Why? Because, horrifyingly enough, the case of Kitty Genovese is not a unique one. In 2011, two-year-old Yueyue was run over twice and ignored by eighteen passers-by. In that same year, multiple employees at Penn State University witnessed Coach Jerry Sundusky’s abuse of his students but failed to report it to the authorities. Every day, schoolchildren stand to the side, afraid, as their peers are bullied. Every day, we simmer in inaction as oppression, pollution, and injustice engulf the world around us. And there that question appears again: Why?
It might be helpful to observe the bystander effect through the lens of science, which is, to put it simply, our way of answering the many why’s about the world.
The bystander effect can be described as the psychological phenomenon where the more people there are present during a certain catastrophe or moment of distress, the less likely it is that an individual person will intervene or assist the victim(s). To better understand this strange element of the human condition, social psychologists John M. Darley and Bibb Latane have introduced an interesting mechanism: the ‘diffusion of responsibility.’ According to Darley and Latane, the ‘diffusion of responsibility’ is something that, as the size of a group increases, decreases the probability of individual intervention in a possible situation. This reveals an interesting pattern: The probability of assistance is inversely proportional to the numbers of bystanders present.
Further insight into the bystander effect can be found at the neurological level. Recent research has offered valuable insight into how the presence of bystanders influences automatic brain responses that are associated with action preparation. In one specific fMRI investigation conducted by Ruud Hortensius and Beatrice de Gelder, the number of bystanders in videos of an emergency were manipulated while participants performed a colour-naming activity on an MRI scanner. It was found that as the number of bystanders increased, activity in their left precentral gyrus, left postcentral gyrus, and left medial frontal gyrus of the brain decreased. These regions are associated with motor and somatosensory preparation (the brain’s readiness to act), as well as social cognition and action planning.
In addition, a comprehensive model introduced by William Graziano of Purdue University and his colleagues posited the existence of two psychological systems: A reflexive, personal-distress freeze system (System A) and a sympathetic, help preparation system (System B). The likelihood that a helping behaviour will occur is dependent on the net result of the two systems, with helping behaviour promoted by System B. It was found that the presence of bystanders during an emergency increases activity of System A, which decreases the probability of helping and increases bystander apathy.
But how is this possible? How can it be that togetherness can drive us apart? How can we sit and watch as the world burns, telling ourselves that someone else will put the fire out? Perhaps these questions are beyond the realms of psychology and neuroscience; perhaps they are not. The research that has been conducted to decipher the bystander effect has made one thing clear: In the face of a crowd, our brains gravitate towards inaction and complicity. This is a disheartening idea, and one that is supported by the past and present conditions of society, but it might not be a steadfast one. We might live in a world of a thousand bystanders, but we also live in a world of a dozen revolutionaries. There are, after all, those who rebel against the wiring of their brain chemistry, who put out the world’s fires. If not, we would have already burned ourselves down to the ground.