READING PASSAGE 3
You should spend about 20 minutes on Questions 27-40, which are based on Reading Passage 3 on pages 11 and 12.

Thinking for Themselves
Some Insights into Animal Intelligence

In 1977, Irene Pepperberg brought Alex, a one-year-old African gray parrot, into her lab at Harvard University to teach him to reproduce the sounds of English. At that time, most scientists considered animals mere machines, lacking the ability to think in a rational way or feel emotions as humans do.

"I wasn't trying to see if Alex could learn a human language," said Pepperberg. "My plan always was to use his imitative skills to get a better understanding of avian cognition." Given that Alex's brain was the size of a walnut, most researchers thought Pepperberg's study would be futile.

But by the time Alex died in 2007, he knew 150 words, could count, do simple arithmetic, and distinguish between objects according to shape, color, and material. Many of Alex's skills, such as his ability to understand the concepts of "same" and "different," are generally ascribed only to higher mammals. But parrots, like higher apes (and humans), live in complex societies and need to monitor changing relationships and environments.

"They need to distinguish colors to know when a fruit is ripe or unripe," Pepperberg noted. "They need to categorize things—what's edible, what isn't—and to know the shapes of predators. And it helps to have a concept of numbers if you need to keep track of your flock. For a long-lived bird, you can't do all of this with instinct; cognition must be involved."

Just how easily mental skills can be acquired is perhaps best illustrated by dogs. For abstract thinking, humans employ symbols, letting one thing stand for another. And Juliane Kaminski, of the Max Planck Institute for Evolutionary Anthropology in Leipzig, believes that dogs can do this too.

In 2008, Kaminski and her colleague Sebastian Tempelmann conducted an experiment with a border collie. The dog successfully selected and brought her owner toys which she had never seen before, prompted only by a picture of each toy.

Creativity is another skill that seems to have evolved in humans and animals alike. "People were initially surprised to discover that chimpanzees make tools," says behavioral ecologist Alex Kacelnik. "But then people thought, ‘Well, they share our ancestry—of course, they're smart.’ Now we're finding these kinds of exceptional behaviors in some species of birds."

New Caledonian crows, for example, use their beaks and claws to fashion tools to poke out grubs from palm trees. "But the problem is we don't have a recently shared ancestry with birds—our last common ancestor was a reptile living over 300 million years ago."

Kacelnik and his researchers at Oxford University were particularly impressed with the ingenuity of one of the crows—Betty, a wild-caught female. In one experiment, Betty successfully selected a hook-shaped wire to get a piece of meat from a glass tube. Then, when another bird unexpectedly stole the hook, Betty took a straight piece of wire, shaped it into a hook, and retrieved the food.

"This was the first time Betty had seen a piece of wire like this," Kacelnik says, "is a major kind of cognitive sophistication."

We are clearly not alone in our ability to invent or plan—or even to plot and lie. Studies show that western scrub jays can guess another bird's intentions and act on that knowledge. A jay knows that if another jay watches it hide a nut, there's a chance it will be stolen.

So the first jay will return to move the nut when the other jay is gone. "It's some of the best evidence so far of experience projection in another species," says Nicky Clayton of Cambridge University.

What's more, the jays seem to know how long ago they hid a particular kind of food, and they manage to retrieve it before it spoils. Human cognitive psychologists call this ability "episodic memory" and argue that it only exists in species that can mentally travel back in time.

They believe that animals cannot distinguish among past, present, and future the way humans do. Such skepticism is a challenge for Clayton. "We have good evidence that jays remember specific hiding events, which is the original definition of episodic memory. But now the goalposts have moved. Whenever we find a mental skill in a species that is reminiscent of human ability, the human cognition scientists change the definition."

Cognitive psychologist Louis Herman has spent decades studying bottlenose dolphins. These intelligent mammals are highly interactive, social, and cosmopolitan, living in subpolar to tropical environments worldwide.

Among the many skills exhibited by Herman's dolphins is the ability to imitate the motor behaviors of instructors. If a trainer bent backward and lifted a leg, the dolphin would turn on its back and lift its tail in the air.

This requires the imitator to form a mental image of the other individual's body, then adjust its own body accordingly—actions that imply an awareness of one's self, an ability once seen as the sole preserve of humans.

What Herman finds fascinating is that these aquatic creatures diverged from primates millions of years ago. "That kind of cognitive convergence suggests there must be some similar pressures selecting for intellect. We don't share their biology or ecology, but we do share the need to establish life-long bonds and alliances. This appears to be the likely common driving force."