What’s so great about human intelligence?

Human intelligence has been the standard against which other species’ cognition is typically compared, with the unspoken assumption that intelligence is good. The modern science of animal cognition has revealed that many species – from chimpanzees to honeybees – can think about the world in complex, human-like ways.

But is ‘thinking like a human’ necessarily all that great, evolutionarily speaking?  There’s an argument to be made that human intelligence is neither the marvel of evolution we thought it once was and might, in fact, be a problematic adaptation for any species.

Consider one of the hallmarks of human-like intelligence: our ability to understand causality. It was once thought that only humans could comprehend the reasons why things happened. A dog might understand that seeing lightning would soon be followed by a scary thunderclap. This is a basic learned association denoting a correlation between two events. But only humans – we once thought – could reason that some property of the lightning was causing the thunder.

But some animal species do, in fact, have the capacity to grasp causality along these lines. In experimental conditions, crows, for example, are extremely nervous of a stick that suddenly emerges from behind a hole in a wall. If they saw a human first duck behind the wall before the stick emerged, that’s fine; they can infer that it was the human moving the stick.

But in the absence of a human behind the wall, there is no causal explanation for the stick’s movement, and thus there’s cause for concern. Being able to reason about causality along these lines gives crows an advantage when foraging for food as they have deeper understanding of why things in the world behave the way they do and can predict how things in the world ought to behave.

For humans, this kind of causal reasoning is the bedrock for our capacity for science itself, which led to all our achievements in engineering, medicine, physics, biology, etc. But is causal reasoning really such a big deal? Most animals on this planet get by just fine without it. A dog hiding under the bed when she sees lightning behaves the same whether she understands that thunder is caused by lightning or is simply correlated with lightning.

And since causal reasoning is what has given us weapons of mass destruction and created the industrial conditions that led to the current climate emergency, maybe it’s not going to work in our species’ favour in the end. If crows were to continue to evolve a deeper capacity for causal reasoning, would they not fall victim to a similar technology-induced existential crisis due to their hyper-intelligence?

Who needs language?

This kind of double-edged sword problem is true for other cognitive skills that we once thought were the sole domain of our species. Consider the human capacity for language. Only humans have the ability to convey information about all the thoughts in our heads via the complex symbol-manipulation system that we call language.

While animals lack full-blown language, animal communication is far more complex than we once believed. Chickens, for example, have dozens of different calls that they make in various contexts, including a ‘food call’ that they make (especially roosters) when they discover food. The call is referential in that it ‘refers’ to the food much like a human word refers to an object/concepts/event.

If a hen hears a food call while already eating food, she is far less likely to run over to investigate the new food source. This suggests that the hens understand that the call truly refers to food and isn’t just a sound that triggers an automatic food-search response.

Imagine, then, that chickens continued to evolve their ability to use referential calls, and one day possessed something akin to human language. Would they be a more successful species? Arguably not. The evidence shows that since all non-human species do not possess language, language isn’t really that big of a deal from a biological perspective.

Animals get along just fine without. And then there’s the major drawback to language: humans often use it to manipulate the behavior of others for their personal gain. Language allows us to lie easily, which is why most people tell at least two lies per day, and some people (1 in 10) are pathological liars, telling dozens of lies each day. You don’t have to read many current headlines to understand that lying and disinformation – although advantageous at an individual level sometimes – is at the heart of human conflict. For all the beauty it generates, language itself is a dangerous tool that might in fact be a liability for any species that develops it.

Theory of mind

Of course, lying through language requires another sophisticated cognitive skill that we once thought was unique to humanity: the ability to understand (and thus manipulate) the thoughts of other people. Humans understand that other humans have beliefs and desires of their own; a skill called Theory of Mind. It’s perhaps no surprise that our closest living relatives – the great apes – might have some form of Theory of Mind as well.

Experiments show that chimpanzees are aware when a food reward is out of the line of sight of another chimpanzee, and will sneakily grab the food without alerting their rival to its location. Dogs too will steal food when a human is not looking, as many dog owners know well. Dogs can also learn that some human experimenters know more about the location of a food reward than others, and choose to follow the pointing finger of the more reliable/knowledgeable human to the food source.

Having a complex Theory of Mind is integral to the capacity for lying. Because humans are so skilled at guessing what others think and believe, we are also skilled at manipulating those beliefs. Which is how we end up with charismatic cult leaders who can convince groups of people to engage in objectively terrible behaviour from an evolutionary perspective, like mass suicide. Theory of Mind too is a double-edged sword. Chimpanzees and dogs do not have cult leaders, and are probably the better for it.

Another double-edged sword

Of course, most humans are not pathological liars or dangerous cult leaders. We have a capacity for goodness and moral reasoning that we once believed was unique to our species. But that too is outdated thinking. Animals have normative systems – a cousin of moral systems – that guide their social behavior.

Chickens, for example, have a pecking order that dictates which hen gets first access to food. This hierarchy is both created and mediated by an in-built sense of what is allowed and not allowed in chicken society – a normative system that each hen is born with. Experiments show that our primate relatives are born with a sense of fairness, with a famous experiment showing that capuchin monkeys will get angry if they are given a lesser food reward to their companions when participating in the same experiment.

And yet the human moral sense is far more complex, with a unique capacity to think about, codify, and rationalise our rules for what is and is not allowed in terms of behaviour. But it’s precisely this ethical thinking that has generated some of the worst atrocities for our species, with moral reasoning leading some past (and current) societies to justify war and genocide. In that sense, the unique human moral reasoning capacity doesn’t necessarily result in particularly compassionate (or biologically beneficial) behaviour.

As research into animal cognition continues to blossom, it is inevitable that we will discover more species that have complex cognitive capacities we once though the sole domain of humanity. But given the destructive power of human intelligence, this might not necessarily be cause for celebration.

• Justin Gregg an Adjunct Professor at St. Francis Xavier University, and a Senior Research Associate with the Dolphin Communication Project.
• If Nietzsche Were a Narwhal: What Animal Intelligence Reveals About Human Stupidity is published by Little Brown.