Brain imaging study reveals blunted empathic response to others’ pain when following orders


A brain imaging study has found that inflicting pain on another person in compliance with an order is accompanied by reduced activation in parts of the brain associated with the perception of others’ pain. The study was published in NeuroImage.

There exists a well-documented psychological phenomenon where people will go to great lengths to comply with authority even if it means harming others. The most famous example is the Milgram experiment, where subjects pressed a button to deliver what they believed were increasingly painful electric shocks to strangers at the request of experimenters. While this experiment has been widely replicated, researchers Emilie A. Caspar and associates point out that studies have yet to uncover a neurological explanation for this effect.

Caspar and her colleagues set out to explore the possibility that causing someone pain under someone else’s direction reduces empathy for that pain. With a brain imaging study, they tested whether being coerced to inflict harm on someone would be associated with reduced activation in areas of the brain involved in the perception of others’ pain, when compared to inflicting the same harm out of one’s own free will.

The researchers recruited 40 subjects with an average age of 25 to partake in their study. The participants were paired up, and each took turns being the ‘agent’ and the ‘victim’ in a controlled experiment. During a series of trials, the agent had control of administering a mildly painful shock to the victim who was seated in another room. The agent received a small monetary reward of €0.05 for every shock given.

Importantly, the agent went through two different conditions. In the coerced condition, an experimenter who was present in the room instructed the agent on whether or not to deliver a shock at a given trial. In the free condition, the experimenter remained in another room, and the agent was told that they could choose whether or not to give the other participant a shock. Throughout the entire task, the agent’s brain activity was recorded using a magnetic resonance imaging (MRI) scanner.

As expected, the agents delivered more shocks during the coerced conditions than the free conditions. While in the coerced conditions, the experimenters had ordered the subjects to deliver shocks on half the trials, in the free conditions, the subjects delivered less than that with an average of 23 shocks out of 60 trials. The agents also reported feeling more “bad”, more “sorry”, and more “responsible” for administering the shocks in the free conditions, compared to the coerced conditions.

Interestingly, when obeying orders, the subjects appeared to downplay the pain they were inflicting. While administering each shock, the subjects could see a live video of the victims’ hand reacting to the shock with a visible muscle twitch. After each shock, the agents rated how painful they believed it was. The researchers found that the subjects rated the shocks as less painful when they were administered as part of an order — despite having been told at the beginning of the experiment that the shocks would be of the same intensity at every trial. “Here,” Caspar and her team emphasize, “our results would support the fact that obeying orders has such a strong influence on the perception of pain felt by others that it even impacts perceptual reports of observed shock intensity rather than only modulating how the observer feels about the pain of the other.”

The MRI results offered further evidence that obeying orders alters one’s empathy response. When researchers zeroed in on areas of the brain associated with the processing of others’ pain — areas such as the anterior cingulate cortex (ACC), dorsal striatum, middle temporal gyrus (MTG), temporoparietal junction (TPJ), and insula — they found that these areas showed reduced activation during the coerced condition. As the authors illustrate, “even in the case of a pain that is fully caused by the participants’ own actions, brain activity is altered by a lack of responsibility.”

The authors note that previous research has suggested that parts of the ACC and insula show greater activation when people are uniquely to blame for others’ pain. This falls in line with the current findings since the coerced condition was linked to reduced feelings of responsibility and reduced activation of the ACC and insula.

Overall, the findings present the unsettling possibility that following someone else’s order “relaxes our aversion against harming others” even if we are the ones carrying out the action.

The study, “Obeying orders reduces vicarious brain activation towards victims’ pain”, was authored by Emilie A. Caspar, Kalliopi Ioumpa, Christian Keysers, and Valeria Gazzola.

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