Subjecting rodents to stimuli can teach the animals to categorize them. However, it is a time-consuming effort which should be taken in compliance with a certain procedure. Not unlike monkeys, rats “communicate” with researchers during an experiment. On the other hand, they give up working with man in case a task assigned to them is far too difficult to fulfill.
According to Conrad Lorenz, a well-known expert in animal behaviors, it is curiosity or rats’ cognitive reflex that turned rats, especially Norway rats, into true cosmopolitan creatures populating virtually every corner of dry land on the planet. The rats look set to sneak into any holes possible, aiming to move into a new environment despite potential inconvenience and even risks. As it turns out, the risk they are running is probably a well-calculated risk.
Citing the online version of the journal Current Biology, InformNauka reports on recent findings by comparative psychologists at University of Georgia. Researchers claim that rats appear to be capable of a complex form of thinking – the capacity to reflect on what they do and do not know. Researchers also claim that rats will give in if forced to cross the limits of their cognition.
The test involved a series of noises played to the rats. The noises were either short (about 2 seconds) or long (about 8 seconds). The rodents had to classify the recent noise by pressing one of two levers. If they were able to classify the noise correctly, they were rewarded with six food pellets. Failure yielded nothing. The rats could always bail out of the test by poking their noses into a hole (a feedbox) and receive three food pellets.
The rats had to classify noise as either short or long. They paid no attention to the feedbox as long as the noise was either very short or very long, and therefore easy to classify so that they could get food by pressing the right lever. However, the decision was a lot harder if the noise was easily confused as either short or long e.g. around 4 seconds long. The rats made twice as many attempts to get food in the feedbox and disregard the levers as the test grew more difficult. They opted to decline the test once the feedbox was removed out of their cage.
The researchers believe that their findings show evidence that rats are aware of the limits of their knowledge in the same way monkeys and dolphins are. A number of comments pointing out that “rats think like humans” followed the publication of the study. Do rats really have this capability?
“The details available so far make it rather difficult to reconstruct an exact procedure of the experiment,” said Alexander Gorkin, a senior researcher with the Institute of Psychology under the Russian Academy of Sciences, in an interview to Nezavisimaya Gazeta. “Other studies show that rodents can be taught to categorize stimuli when the former are subjected to them. However, the process is a time-consuming effort to be taken in compliance with a certain procedure. We can’t be sure whether the category of a ‘short’ and ‘long’ noise was clearly defined during the test. It’s quite possible that the rats were at their early stage of learning. They may have simply guessed the right lever. It stands to reason that the success rate started to drop as the noise became increasingly easy to confuse – for instance 4.4 seconds, hence resulting in a fifty-fifty chance of success.”
Moreover, Alexander Gorkin is confident that another important factor should be taken into account. According to him, there are cases when rats and monkeys alike can decline to “communicate” with researchers if the task of an experiment gets far too difficult to fulfill.
“I’ve witnessed those cases while getting rats to perform a short-term memory task. It was obvious that the lab animal showed its attitude toward the researcher by declining to do things required under the test. The animal would resume working in a short while once the researcher left the laboratory. All in all, the “bounds of knowledge” or a lack of past experience required for solving a problem usually results in a situation of instruction provided there is express motivation involved. Therefore, declining to work outside the “bounds of knowledge” relates directly to communication between an animal and a researcher,” said Gorkin.
As for the excellent communicative abilities of Norway rats, they have been known for a long time. Aside from rocks and other ordinary objects, a variety of other things e.g. light bulbs, spoons and wrappers are regularly found in rats’ burrows. There is documented evidence showing the ability of the rat to extract liquid out of a bottle with the help of its tail. There are reports on rats which could make a bottle half empty in no time. They would stick their tails in the bottle and then withdraw them for licking up.
Everything considered we cannot but agree with our expert: it would be wrong to use a prism of anthropomorphism for looking into the behavior of the rats, which are, without doubt, very smart creatures. In other words, we should not project onto animals the concepts of cognition and consciousness attributed to humans.
“The logic on which this publication is built seems to hint at some hidden recognition of knowledge and consciousness possessed by animals. Taking into consideration the meaning of the above terms as seen by psychologists, the assertion looks rather doubtful,” Gorkin emphasized. “Knowledge implies the possibility of its verbalization and formalization, the possibility of passing it to another individual. Consciousness is interpreted as knowledge shared. Various species of animals were found to be capable of detecting the novelty of stimuli (or “capable of reflecting on their own cognition” if we use the wording of the article). Scientists gathered enough evidence to prove the capacity back in the second half of the 20th century. Besides, using the verb “reflect on” implies evidence of consciousness found in rats though nobody has ever reached such a conclusion even with regard to great apes,” Gorkin added.
Translated by Guerman Grachev