Twenty-eight years ago, two people who likely wouldn’t have ever looked at each other on the street fell in love because they each liked the way the other thought. He was just getting over a rough breakup and getting through his residency at a Chicago hospital; she was an intern who wasn’t terribly interested in his partying habits. But the more they saw each other, the more they realized that the circuits behind their eyes lined up.
Twenty years and three kids later, they still got along because they used the same logic.
Humans attribute a lot of value to the way that we think. Our logic overrides many of our basic wants and desires, and occasionally, our wants and desires override our logic. The reasoning systems we use are relatively unique among animals, or so we think.
A recent study found that rats use similar logical sequence processes, inferring a cause-and-effect relationship to certain actions. This inference of cause and effect, a hallmark of learning systems, allows rats to develop reactions based on past experiences, remarkably similar to the way humans learn.
Researchers at the University of California, Los Angeles conducted an experiment on rats to test whether they can learn complex systems as related to their results. They keyed the rats to expect food when a light came on and a tone played, creating a Pavlovian reaction. However, the rats were able to eventually infer multiple extra logical conclusions. For one, they knew that if the tone played and there was food, the light must have come on somewhere; if they saw the light but heard no tone, they expected it to play somewhere. Additionally, when they were provided with a lever to switch on the light or the tone, they did not investigate for food because they recognized that they had caused the tone and had no ability to provide the food for themselves.
Rats can also use counterfactual reasoning. If they have been conditioned to expect two lights to come on and then one is blocked from vision, they act as though they saw both lights.
Upon deeper investigation, the researchers found a shared mechanism in the hippocampus of both rats and humans. The structure is related to counterfactual reasoning and is age-sensitive, declining over time. Coincidentally, this reminds me of a study published in 2013 that concluded that the short-term memories of mice could be restored through environmental factors, holding hope for Alzheimer’s patients, who lose their short-term memory rapidly.
As always, there is a caveat: humans and rats do think differently. We prioritize different things through learning than rodents do. We are aware of our reasoning at a meta level as well, able to improvise atop our basic functions into different types of reasoning, some more harmful than others. However, studying the rats may give us a baseline for how the physical function of reasoning works.
It may also give us insight into how to treat or communicate with people who have mental disabilities. For example, people with autism tend to draw more strongly from pictorial analogies, drawing appropriate conclusions from the setups presented to them by researchers. Schizophrenic individuals, however, did not. Further study of what types of logic we use in particular situations may help with communication, rehabilitation and treatment.
Reasoning is a fascinating study. Most people who read the news will remember the flare of attention focused on the anti-vaccination movement early in January during the measles outbreak in the U.S. These people have been accused of delusion and fraud, and potentially they are delusional. However, Seth Mnookin explored their psychology in a fairly graceful way in The Panic Virus. The proliferation of the Internet may also propel these circular cycles of thinking. I once read an accurate description: “we have become a society of echo chambers.” We can choose to hear, read and believe only what we want to, forming our thinking processes.
And that is a thing worth studying.
In Situ 