Rats prefer to help their own kind; humans may be similarly wired

Recently the largest company that supplied mice and rats for scientific experiments in Australia announced that it was closing down. Many researchers threw up their hands in horror and desperation. Not I. Though I am happy to selectively report on these experimenters’ work I am nevertheless appalled at the number of experiments involving these rodents that serve no scientific purpose that I can discern. Even in experiments that are “non-invasive” usually result in the animal’s death.

And the truth is that we are coming to the end of the era of using animals for experimentation. Much of that work can be done by computer simulation and other means.

However, many of these experiments have been genuinely useful and could not have been carried out by other means at the time. This is one of them.

A decade after scientists discovered that lab rats will rescue a fellow rat in distress, but not a rat they consider an outsider, new research pinpoints the brain regions that drive rats to prioritize their nearest and dearest in times of crisis. It also suggests humans may share the same neural bias.

The findings, published in the journal eLife, suggest that altruism, whether in rodents or humans, is motivated by social bonding and familiarity rather than sympathy or guilt.

What the researchers say: “We have found that the group identity of the distressed rat dramatically influences the neural response and decision to help, revealing the biological mechanism of ingroup bias,” said the study’s senior author.

With nativism and conflicts between religious, ethnic and racial groups on the rise globally, the results suggest that social integration, rather than segregation, may boost cooperation among humans.

“Priming a common group membership may be a more powerful driver for inducing pro-social motivation than increasing empathy,” she continued.

The research team sought to identify the brain networks activated in rats in response to empathy, and whether they are mirrored in humans. The results suggest they are.

“The finding of a similar neural network involved in empathic helping in rats, as in humans, provides new evidence that caring for others is based on a shared neurobiological mechanism across mammals,” the researchers said.

Using fiber photometry, immunohistochemistry, calcium imaging and other diagnostic tools, researchers found that all the rats they studied experienced empathy in response to another rat’s signs of distress.

However, to act on that empathy, the helper rat’s neural reward circuitry had to be triggered, and that only occurred if the trapped rat was of the same type as the helper rat, or member of its ingroup.

“Surprisingly, we found that the network associated with empathy is activated when you see a distressed peer, whether they are in the ingroup or not,” the lead researcher said. “In contrast, the network associated with reward signaling was active only for ingroup members and correlated with helping behavior.”

Specifically, the rats’ empathy correlated with the brain’s sensory and orbitofrontal regions, as well as with the anterior insula. Meanwhile, the rodents’ decision to help was linked to activity in the nucleus accumbens, a reward center with neurotransmitters that include dopamine, oxytocin and serotonin.

For the study, more than 60 pairs of caged rats were monitored over the course of two weeks. Some of the pairs were of the same strain or genetic tribe while others were not.

In each trial, one rat would be trapped inside a transparent cylinder while the other roamed free in a larger enclosure surrounding the cylinder.

While unconstrained rats consistently signaled empathy in response to the plight of trapped rats, they only worked to free those that were part of their ingroup, in which case they would lean or butt their heads against the cage door to release the rat.

Indeed, in reviewing the results of multiple measures to understand the neural roots of that bias, the research team found that while all the rodents in the trials sensed their cage partner’s distress, their brains’ reward circuitry was only activated when they came to the rescue of a member of their ingroup.

Humans and other mammals share virtually the same empathy and reward regions in the brain, which implies that we may have similar biases toward our ingroup when it comes to helping others.

“Overall, the findings suggest that empathy alone doesn’t predict helping behavior, and that’s really a crucial point,” the lead author said. “So, if you want to motivate people to help others who are suffering, it may be that you have to increase their feeling of belonging and group membership, and work toward a common identity.”

“Encouragingly,” she added, “we find that this mechanism is very flexible and determined primarily by social experience. We will now try to understand how pro-social motivation shifts when rats become friends, and how that is reflected in their brain activity.”

So, what: In human science terms, this is the study of the week. Alicia and I have been saying for a long time that if you want to have genuine collaboration and helping in an organization you have to find ways to increase the sense of commonality on which belonging depends—to get the right brain areas working with the right reward mechanisms.

This, of course, is where culture comes into play. A truly collaborative company, organization or society needs to have a unified culture—a broad commonality of assumptions, norms of behavior and language. In most large organizations—and many mid-sized operations—there are a number of mutually competitive cultures and so genuine collaboration is frequently impossible and real willingness to help others is often missing.