Parnad Basu, Amity University Kolkata
Humans are social animals, and we need each other’s help here and there. At times we do tend to help, but only our friends and family. That is known as prosocial behaviour, where we do something that benefits someone else. However, we are much more reluctant when it comes to helping someone we don’t know. Our prosocial behaviour is determined mainly by sympathy and empathy.
We build a group or team consisting of our close ones. And here comes the concept of ingroup bias and outgroups. Those who we chose to be in the group are ingroup, the rest are outgroup. As it stands, even rats think in the same manner. In a study done by the scientists from UC Barkley, they concluded this behaviour. Rodents like rats also feel stress when they see other rats in distress and try to help them get over it. This behaviour of rats makes them highly sociable, just like us. When these rats were subjected to HBT (helping behaviour test), they showed an ingroup bias.
The recent study:
In this study, more than 60 pairs of caged rats were used over two weeks. The study was simple, they would trap one of the two rats inside of an invisible cylinder. The cylinder had a door that could be opened by the rat that’s outside. Then they would monitor whether or not the outside rat helped the trapped rat. The pairs used in the study were not always of the same strain. In this experiment, male SD rats (Sprague-Dawley rats) were tested for HBT in SD rats and a stranger black-caped Long-Evans strain. Male SD rats were tested for both ingroup and outgroup HBT. Each and all rat’s movement patterns were recorded and analyzed.
The results obtained:
The results obtained from this experiment are extraordinary. In the case of the HBT ingroup, male SD rats learned pretty quickly how to free the trapped rat. Throughout the experiment, the percentage of freeing trapped rats increased significantly. Which resulted in decreasing the mean latency to the door opening. Although, in the HBT outgroup, the SD rats rarely opened the door. So, it is noticeable that the SD rats did help the outgroup rats, but not as often. This leads to a question, why didn’t those rats help outgroup rats even when they knew how to open the door. For which we have to take a look at the neural activities of the rats. In both cases, neural activities in the sensory, orbitofrontal, anterior cingulate, and insular cortices were observed.
These regions become active in processing the distress of others; although, that doesn’t guarantee prosocial behaviour. MO (medial orbitofrontal cortex), PrL (prelimbic cortex), Nac (nucleus accumbens), and LS (lateral septum) regions were more active in ingroup HBT conditions. Nac is associated with reward-seeking in rodents like rats. The activation of the Nac region is considered as one of the factors in helping ingroup members. This shows that to help another rat the helping rat needs to feel rewarded. While helping the ingroup members, the SD rats felt rewarded. On the other hand, in outgroup members, they didn’t.
Conclusion:
The key factor in this study was the feeling of belongingness. When the rats felt that the trapped rat didn’t belong to their ingroup, they were less likely to help. These findings are very similar to that of humans. It shows why we tend to ignore helping other humans who don’t belong in our group. For a diverse society of humans, that can cause challenges. However, further studies are needed to see what would happen if two rats with different traits become friends.
Also read: Enhancing diversity and inclusion within the genetics community
Reference:
- Ben-Ami Bartal, I., Breton, J. M., Sheng, H., Long, K. L., Chen, S., Halliday, A., Kenney, J. W., Wheeler, A. L., Frankland, P., Shilyansky, C., Deisseroth, K., Keltner, D., & Kaufer, D. (2021). Neural correlates of ingroup bias for prosociality in rats. ELife, 10, e65582. https://doi.org/10.7554/eLife.65582
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