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Networks in relation to Rats

These two studies were conducted to study the existence of empathy and pro-social behaviors in rats based on a number of different variables, and they ultimately reveal very telling information about social networks in the context of rats.

The earlier of the two studies found that the majority of free rats would attempt to open the cage for their trapped friend. The study notes that they did this even though it required overcoming the ‘acquired/shared distress’ it received from it’s trapped compatriot in order to figure out how to open the door. In successive trials after the rat has figured out the door-opening mechanism, the rat would consistently and immediately open the door.

This particular study also tested by leaving the cage empty or substituting the cagemate with a stuffed toy, which the free rat would not open the cage for – meaning the cage-opening action was motivated purely by empathy. The scientists obtained further proof of this by discovering that when they placed a closed container of chocolate into the area in addition to the cage containing the trapped rat, the free rat would share the chocolate with it’s formerly trapped cagemate in a little over half of all trials. As a side-note, when the test was done with the trapped rat being released into a separate area from the free rat, the free rat would still consistently release the trapped rat, indicating that they weren’t doing this for social reward/to play with the trapped rat.

What this study shows is that, based on a strong positive link with an individual, rats will consistently ‘go to bat’ for their friend by overcoming their own distress to free them. Additionally, the chocolate trials show that game theory, while perfectly reasonable on paper, does not translate as neatly into reality. The free rat had the opportunity to eat all of the chocolate before freeing it’s friend, but chose the personally sub-optimal option of sharing the chocolate. It received no visible reward or aversion of negative consequences for this seemingly altruistic action, as the study didn’t note any attacks or refusal to socialize or any other perceivable displays of displeasure from the chocolate-deprived cagemates, yet did so anyways – although it is quite possibly motivated by the rats strong link with its cagemate.

The second study focused on whether or not rats would free other rats from a cage, and in what order, based on several different variables – whether or not the trapped rat was: a cagemate, the same strain, a different & unfamiliar strain, or a different & familiar strain. The study concluded by noting that rats would almost always free a cagemate or a stranger of a similar strain, but would refuse to free a rat of a different, unfamiliar strain. However, after being housed with one individual from that unfamiliar strain, the rat would then free any and all strangers of that formerly unfamiliar strain. This very strongly demonstrates the network principle of local bridges in the sense that, by forming that one connection to a single individual from a different group, the rat would be open to freeing all rats from that different group.

At first glance, this study seems to violate the idea of strong/weak ties as the rats (the nodes) would consistently open the doors very quickly for familiar strain strangers as they would for cage-mates – but if you consider the situation such that a strong link denotes personal familiarity with the rat (a bi-directional tie) and a weak link is at least familiarity with the strain (a one-directional tie), then the principle holds true. The study states that “since rats tested with strangers from unfamiliar strains did not become openers across the days of testing, the exposure and interactions afforded by testing sessions appear insufficient to produce pro-social motivation”, indicating that these small interactions would not constitute even a weak link, which is the bare minimum for a rat to open the cage.

The study also conducted trials where rats of one strain were fostered from the day of birth to rats from a different strain before being placed in the same area as a caged rat from their own strain, whom they had no prior experience with. The results indicate that the fostered rat would refuse to open the cage for these rats because they’d had no prior interaction with them, even though the caged rats were the same strain as them. This primarily feeds into the idea that strong links are formed through constant/repeated social interaction, as opposed to genetically dictated – which basically voids the idea that “blood is thicker than water”.

Ultimately, these studies have relatively important implications when applied to human social structure and interactions in the context of different races/ethnicities and other dividing factors such as culture, nationality, and religion, to name a few – and in the context of human biology with the idea of nature vs nurture. It also has overreaching significance in terms of re-defining some of our ideas regarding animals and their intelligence and behaviors – particularly in the light of similar studies, such as the one indicating that animals such as sharks, slime molds and snakes are also fairly intelligent, although perhaps in different ways.

References;

http://elifesciences.org/content/elife/3/e01385.full.pdf

http://www.sciencemag.org/content/334/6061/1427.full

 

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