Are we better than rats? Before you answer that seemingly easy question, you may want to hear the results of a new study which found that our least favorite vermin go out of their way to avoid hurting other rats and the area of the brain used is the same one that controls empathy in humans. Do they feel the same way if they find out the other rat belongs to a different political party?
"Much like humans, rats thus actually find it aversive to cause harm to others."
In a study that would be taught in every rat hole and school if rats could read (has anyone checked for that?), neuroscientists at the Netherlands Institute for Neuroscience (NIN) developed a simple test to determine if rats showed “harm aversion” – a moral trait of most humans that causes them to feel bad about hurting fellow humans. It has long been accepted that humans have empathy towards each other while animals are selfish – caring only about the well-being and safety of themselves and their offspring to the detriment and sometimes demise of strangers and even group members of the same species.
“The scientists gave rats a choice between two levers they could press to receive candy (sucrose pellets). After the rats had developed a preference for one of the two levers, the scientists rewired the delivery system so that pressing the preferred lever also delivered an unpleasant electric stimulation to the floor of a neighboring rat. The shocked neighbor reacted by squeaking their protest.”
In a study published in Current Biology and summarized in a press release, the researchers reveal that rats who saw that their pleasure meant pain for another rat – even a rat they’d never seen before – would stop pressing the lever. This so shocked (with no associated candy) the researchers that they decided to see if this trait was connected to the same part of the brain that controls empathy in humans. The results were even more … you know the word.
“In humans, functional magnetic resonance imaging experiments show that the anterior cingulate cortex, a region between the two hemispheres of the brain, lights up when people empathize with the pain of a fellow human. The researchers had recently shown that the same region in the rat contains emotional mirror neurons—neurons that map the witnessed pain of another rat onto the witness' own pain neurons. In the present study, they reduced brain activity in the same region in the rat by injecting a local anesthetic and observed that rats then stopped avoiding to harm another rat for candy.”
OK, that part sounds like the plot of a movie about a mad scientist creating a race of sociopathic, killer rats. While the experiment shows that rats have some form of harm aversion towards fellow rats that is similar to empathy in humans, it doesn’t test what the trigger might be. The sounds of other rats in pain? An inherent sense of animal morality? Some unknown rat religion? While those questions will obviously mean more grant money for new studies by rat researchers, it also has implications for human psychologists and social scientists studying empathy, morality and the lack of those traits in sociopaths. It may mean that all humans have the trait – independent of religion or other spiritual or moral influence or training – and something physical drives or allows some humans to kill or viciously harm fellow humans.
Does this mean that humans exhibiting sociopathic or even mere antisocial behavior should have their brains examined? Should some sort of physical or drug treatment be developed? What could possibly go wrong? Does this sound like a movie plot or something that could be (or perhaps has already has been) exploited by an evil government? Professor Christian Keysers, co-author of the study, looks at the good side.
"Whatever the motive, that we share a mechanism that prevents antisocial behavior with rats is extremely exciting to me. We can now use all the powerful tools of brain science to explore how to increase harm aversion in antisocial patients."
Perhaps we should learn as much as we can from rats before we eradicate them from the planet.