The Social Brain

Why the social brain is the most intelligent brain

Dolphins, known as one of the most intelligent animals, seen off Montauk, New York. Credit: Carl Safina

Dolphins and humans have not shared a common ancestor for tens of millions of years. Yet for all the seeming estrangement of lives lived in liquid, when they see us they often come to play, and we can recognize in those eyes that someone very special is home. “There is someone in there. It’s not a human, but it is a someone,” says Diana Reiss.

Different species’ brains emphasize different abilities. The nerves and brain structure for detecting and analyzing scent is an important part of a dog’s brain but essentially nonexistent in a whale’s.

Meanwhile, a sperm whale’s brain devotes enormous resources to creating, detecting, and analyzing sound. Sperm whales’ brains are larger than blue whales’, though blue whales’ bodies are twice as big. What does a sperm whale do with its singular brain? It sets courses for long migrations and keeps track of family and friends over decades, and across thousands of miles of travel. It prepares for dives deeper than a mile; manages the pumping, distribution, and shunting of blood and oxygen while the whale stops breathing for up to two hours; and controls the tracking and muscle coordination needed while hunting squid the size of your nightmares in total darkness.

If you’re going to have a larger, denser brain, you’re going to have to pay to run it. And brains are real energy hogs. At just about 2 percent of our body weight, ours costs nearly 20 percent of our body’s energy budget (that’s why mere thinking can be so tiring).

Chronic energy budget overruns can kill; in hard times if you run out of calories, you starve. So why risk having a big brain? Either it’s greatly needed or it conveys some incisive advantage. It’s not greatly needed. Plenty of less smart species survive very well, thank you.

Killer whales cleverly hunt salmon, but they’d be more abundant if they simply were salmon. Dolphins often share the same waters with tuna, hunting the same prey. Tuna are more energy efficient, and there are more of them. Spiders and insects succeed in their trillions with small brains. So why pay the added freight of a big brain? Why do dolphins pay to be smarter than tuna; why do elephants pay to be smarter than antelope?

Killer whales in British Columbia. Instead of eating salmon, they’d be more abundant if they were simply salmon. Credit: Carl Safina

Tuna are smart in their ways and are marvelous creatures. But tuna don’t travel with their young at their sides during years of learning; they don’t aid wounded companions or summon one another. Big differences. Social differences.

Wildebeest eat grass, and elephants eat grass. Grass eating isn’t why elephants are more emotionally and intellectually complex. But if you’re an elephant or an ape you have to keep track of specific individuals you meet repeatedly, who might want your food or your mate or your rank and who might plot against you, or might plot with you against your rivals, or be there for you when it matters; you need to consider cooperation and competition among different individuals.

When individuals matter — when you’re a “who” — you need a social brain capable of reasoning, planning, rewarding, punishing, seducing, protecting, bonding, understanding, sympathizing. Your brain needs to be your Swiss Army knife, packing different strategies for different situations.

Dolphins, apes, elephants, wolves, and humans face similar needs: know your territory and its resources, know your friends, monitor your enemies, achieve fertilization, raise babies, defend, and cooperate when it serves you.

Elephants in Kenya, living and working together to achieve many of the same goals as humans. Credit: Carl Safina

In various dolphins, males form alliances in twos or threes to control access to females in breeding condition. Bottlenose dolphin alliances in Florida last up to twenty years. These tight male alliances sometimes merge into coalitions that overwhelm smaller alliances, stealing their females like human tribal raiders. Think of a street gang, with sonar.

Researcher Janet Mann saw an alliance of male bottlenose dolphins surrounding a single female. A female coalition swooped in, diverting the males by rubbing up against them and stroking them with their fins. After confusing the males by what looked like playing on their sexual interests, the females — all of them — took off. I wonder if they laughed about it.

Alliances can make the difference between who wins and who suffers. When those are the stakes, intelligence matters. Chimpanzees rise in rank by giving favors and by shrewd judgment about whom to rely on or undermine. Researchers call it “a Machiavellian mind.” Primatologist Craig Stanford writes, “Male chimpanzees have political careers, in which the goals stay more or less the same — wield as much power, influence and reproductive success as possible — but the tactics for achieving them vary from day to day, year to year, and life stage to life stage.”

Why all the effort, expense, and risk for status? Because the highest- ranking male usually fathers the most babies, to whom the highest-ranking female, most frequently, gives birth. Since the behavior reproduces itself, it perpetuates.

That’s what status seeking is about, whether we status seekers realize it or not. In social settings, intelligence can help you get reproductive access to quality mates. Species who have the most complex societies develop the most complex brains. Take-home: the most intelligent brain is the social brain.

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This piece is adapted from Carl Safina’s most recent book, Beyond Words; What Animals Think and Feel, which is newly out in paperback.