The hypothesis dump

As humans, we are not objective when investigating the capabilities of other species, especially regarding mental faculties. There is a tendency to view ourselves in a superior position. But the question remains: Is this due to our innate egocentric view, or is it an actual reality?

I once had a casual conversation with fellow neuroscientists regarding species differences in intelligence. First off, what is intelligence? To avoid turning this article into a book, I will skip the effort of answering that question. Nevertheless, my colleagues held the common view that humans possess intelligence superior to any species known to us thus far. On the surface, most people would not question this. However, how do we objectively compare this ability between species?

One way would be to test different species in different cognitive abilities. For instance, you could devise a task that tests different species in problem-solving and see if there are differences in their accuracy and speed. Or, you could test different species in a memory task. Collect some data on accuracy and time spent on each trial, plot it in a graph, and then check who wins!

Herein lies the issue: what task could you use across species, from fish to birds to mammals? Firstly, you need to identify a task that mitigates the different physical limitations of the tested species. You cannot have a task that gives the apes with opposable thumbs an edge over the birds; this would be a confounding factor unrelated to cognitive ability. Already, there is a huge hurdle.

Now, let’s say you pass that particular hurdle. Next, and probably the biggest issue, is that every species has a different strategy for higher fitness in a given environment. We have all evolved on different paths, which means the designed task has to account for biological relevance in every species. For example, if we design a task to identify images of landscapes or patterns, who do you think would be superior?

If we are talking about landscapes, I would argue birds. In a study by Levenson et al. (2015), they found that it was possible to train pigeons to detect breast cancer. They were able to learn the visual difference between benign and malignant tumors. Now, that may sound surprising, but in fact, birds are adept at memorizing and recognizing visual landscapes as they have evolved to do so. This is because it is a necessity if you are going to navigate in the sky. If I take the average human and put them in the sky, do you think they would be able to navigate home or identify areas based on what they see?

I doubt that they would perform as well as a pigeon. Does that mean that birds are as intelligent or more intelligent than humans? Or, if I take any average human and drop them in the wild, could they survive as well as any wild animal? I doubt that as well. Does that mean that they are more intelligent than humans? No, it does not. It only means that birds, for instance, have evolved a strategy for their fitness that was necessary in their particular environment.

Humans are amazing at generating, using, and recognizing symbols, a fascinating ability you are doing right now by reading these symbols. These translate in your mind to reflect my mind upon yours. That is an amazing ability that could have developed in humans out of necessity, when we started living in cities. It could have been made possible by humans evolving complex vocalization and all its language nuances, along with corresponding brain areas. Does that mean humans are more intelligent than other animals?

Well, that at least tells us humans are unique in the complexity of language. This is not a minor thing; it allows us to transfer knowledge to others and down the generations. It facilitates development and building upon existing knowledge. Add on tool-making ability, and you get most of the tech we have today and the capability of R&D. What an ape!

Now, let’s go back to the original question: Are humans uniquely intelligent? It depends on what we mean by intelligence. If we account for every cognitive faculty in existence, average each across every species, and compare, what probably would happen is that differences in abilities within a species would cancel each other out, and every species would fall in the center. Meaning, there is no difference if you compare every single cognitive ability. But! If we say that intelligence is the ability to learn information about our environment and transfer what we learned to other individuals, then humans are the most intelligent species. If we say that intelligence is the ability to survive and procreate, well, then certain microorganisms would surpass us. Or, if we speak of navigating from the air, then birds take would the lead. So, what do you mean?

Declaration of AI use: The author used Lumo AI for spelling and grammar-checking during the preparation of this article.

References

Levenson RM, Krupinski EA, Navarro VM, Wasserman EA (2015) Pigeons (Columba livia) as Trainable Observers of Pathology and Radiology Breast Cancer Images. PLoS ONE 10(11): e0141357. https://doi.org/10.1371/journal.pone.0141357