I could, if I chose to, make this sentence go on and on and on—forever, really. Don’t worry: I’m not going to do that, but it’s noteworthy that I could. In fact, I have the ability to write a sentence that’s longer than the longest sentence previously written, just by adding another relative clause, then another, and so on.
That may seem like a cheesy way to play the longest-sentence game, but it’s actually linguistically clever—very clever. The longest sentence game is not just a parlor trick. It demonstrates an important linguistic principle. The fact that I can think to do this, and that you can understand what I am doing, reveals characteristics of language and of mind that are unique to humans. With a finite store of symbols, I am generating one novel combination after another, all of which you can more or less comprehend. I’m counting on you to understand what I’ve written here, which is in itself remarkable. My idea is now in your head, and, importantly, that pleases me.
I, in turn, am taking these ideas from the mind of Thomas Suddendorf, a psychologist at the University of Queensland, Australia, and author of this fine new book. Even though I have never met Suddendorf, and have never been even close to Australia, I can nevertheless comprehend his thinking and share it with you. Suddendorf’s main idea is that we humans are capable of cognitive feats to which no other animal—not even our impressive cousin the ape—comes close. We are able to imagine endless situations, to create scenarios and narratives about distant places, including the past and future. And, equally important, we have an insatiable drive to share those imaginings with other scenario-building minds. Our uniqueness, the author argues, rests on these two fundamental traits, but plays out in various domains of the human mind.
Language is one of those domains. A lot has been written about the abilities of other species to communicate, and those skills are indeed impressive. Bees signal the whereabouts of food, and birds have elaborate courtship dances. My dog clearly (and effectively) signals that it’s dinnertime by staring. But none of this adds up to language—not as I illustrated it above. Even humpback whales, with their very large brains, show only a narrow repertoire of communication skills, devoid of the flexibility and generative power that allow us to utter and comprehend novel expressions. Suddendorf systematically dismantles the claims of other species on language, arguing that even the great apes—the ones we have spent years trying to teach our language—fall far short of full-fledged language. What’s lacking, in the end, is the motivation to create symbols and grammar to share what’s on their minds.
Some readers, including some scientists, will not agree with this conclusion. Some believe that other animals—especially pets and lab animals—have all sorts of complex mental characteristics, that they are basically “little people in furry suits.” Since we lack verbal self-reports from the animals themselves, they cannot confirm or refute this opinion. Suddendorf labels such readers and scientists “romantics,” meaning that they favor a “rich” interpretation of the existing data. Romantics stand in contrast to “killjoys,” who prefer a “lean” interpretation. Killjoys are reluctant to ascribe any humanlike abilities to animals, and at the extreme, they view other creatures as “mindless bio-machines.”
Suddendorf places himself firmly in the middle, neither an extreme romantic nor an extreme killjoy. His goal is to go beyond opinions and preconceptions and apply the methods of science, especially comparative psychology, to questions about animal capabilities. Only by such prudent and careful analysis of animal abilities is it possible to understand the nature of the gap that separates us from them. Suddendorf’s lofty goal here is to kickstart a “science of the gap” that will define human peculiarity trait by trait.
Consider time travel. Psychological scientists are in agreement that humans have different forms of memory, including episodic memory, or memory for events. When we say that we remember “the good old days,” we’re talking about this capacity. But episodic memory is not comprehensive or reliable—in fact, it’s notoriously unreliable. We recall the gist of something, and then we elaborate it in our mind, and it’s exactly this open-ended cognitive creativity that sets us apart. We are able to use fragments of old information not only to predict the future, but to imagine infinite other futures. This cognitive time machine has been crucial to our success as a species, because it allows us to make plans and decisions about what’s to come. We can anticipate and prepare and reevaluate and change course as needed. And, crucially, we can share our plans with others.
There is no evidence that any other animal has this talent. A few years ago, scientists became very excited when it was found that scrub jays cache food that they retrieve later on. This was taken as evidence of rudimentary prediction and planning; but on closer analysis, Suddendorf sees no convincing evidence of actual episodic memory, much less any true planning, with the jays. Not even the great apes have shown evidence of truly thoughtful planning—carrying an emergency tool kit, for example, as we know primitive humans did. And they fall far short of the sort of long-range planning that sets us aside: devising strategies to reach distant goals, choosing a career, and so forth.
Romantic readers will be racking their brains right about now, trying to recall anecdotes that elevate chimps and dogs and cats. For some people, for some reason, it’s important to be connected to other members of the animal kingdom on an emotional level. You need look only as far as the Internet, where there are entire websites devoted to “dog shaming”—that is, displaying photos of dogs with written “confessions” of their household sins. There are also videos of dogs, caught in the act of this or that, slinking away, their heads downcast in the face of human disapproval. The appeal of these images is presumably a deep-seated desire for dogs to have human emotions like shame and guilt.
But do they? Not according to Suddendorf’s thorough survey of the current evidence. Emotions like guilt and shame require a sense of right and wrong—in a word, morality. Suddendorf borrows primatologist Frans de Waal’s three-level moral hierarchy to deconstruct the moral claims of other animals. According to de Waal, morality requires, at a minimum, empathy and reciprocity, and there is fairly good evidence of such compassion and cooperation in other animals. But beyond that, the evidence is much thinner. There is scant evidence that even our closest relatives establish and enforce social norms (de Waal’s second level of morality), and there is zero evidence that any nonhuman animal engages in true, self-reflective moral reasoning. This is the capacity to contemplate what “ought” to be and to act according to these moral assessments; it is a distinctly human capacity.
Those dogs on the Internet? They may arouse empathy and other emotions in us, but the hounds themselves are most likely feeling and exhibiting a simple fear of punishment. Chihuahuas and gorillas are incapable of high-level moral reflection because their minds cannot build flexible mental scenarios, as our minds routinely do. We alone can reason about past, present, and future motives, beliefs, and actions—and, based on this reasoning, make deliberate decisions about how we will act. No nonhuman comes remotely close to this moral capacity.
So our ability to play the longest-sentence game is profound, and underlies everything from language to time travel to morality—indeed, all human culture. But this exceptionalism comes with daunting responsibilities, Suddendorf believes. This is an important leitmotif that runs throughout the author’s arguments. Because we—and we alone—can anticipate the future and plan our actions, it follows that we have a moral responsibility to do what we can to avert disaster and create a sustainable future. Our future depends on how well we imagine the possibilities of what is to come and our willingness to link our minds cooperatively to solve global problems.
For Thomas Suddendorf, those problems include the extinction of many of the world’s species, even our closest ape relatives, many of which are in danger. If the gap between us and all other animals seems wide, it is because other hominin species that once walked the earth have perished. We weren’t always so special, and it’s good to remind ourselves of that. If these other cousins perish, the gap will widen even further.
Wray Herbert is the author of On Second Thought: Outsmarting Your Mind’s Hard-Wired Habits.