What does it mean to be intelligent? If it’s defined by having the biggest brain, then sperm whales—whose brain is 20 pounds—would be the brightest creatures on Earth. But, more likely, intelligence is what gives an organism the best chance to survive in an environment. Language may be one of the best ways to demonstrate that kind of smarts. Though all animals can communicate with others, humans are one of the few species to have a spoken language. Using speech, we could share complex ideas, pass knowledge through generations, and create communities. Whether spoken language actually helped us evolve (进化) as species into more advanced beings, however, has never really been tested.
“Language allowing humans to be a more advanced species is an assumption that somebody came up with one day without really trying to prove it,” says Erich Jarvis, a professor who studies the neurobiology of vocal learning.
But Jarvis and his colleagues were able to examine this assumption with the help of songbirds. Jarvis’ new study provides some of the first evidence that vocal learning—one of the crucial components for a spoken language—is associated with problem-solving. Vocal learning is the ability to produce new sounds by imitating (模仿) others, relying on experience rather than instinct.
To get a better grasp of vocal learning and cognition (认知), the study authors turned to songbirds. The team performed seven cognitive experiments on 214 songbirds from 23 different species. Of these, 21 species were caught from the wild. Two songbirds studied are domesticated. The behavioral tests examined the birds’ problem solving, for instance by figuring out how to remove an object to access the food reward. The researchers also tested two other skills often associated with intelligence: learning by association, plus what’s called reversal (倒转的) learning, in which an animal adjusts its behavior to get a reward. They then looked at whether being vocal learners helped develop the three skills, comparing 21 bird species to two others, which were vocal non-learners.
The biologists noticed a strong relationship between vocal learning and problem-solving skills. Vocal learning bird species could come up with innovative ideas, such as getting seeds, or a worm trapped under a cup by removing the obstacle or pulling it apart. All three abilities—problem solving, associative learning, and reversal learning—are typically considered “components of intelligence,” he says.
Brain size was another benefit to vocal learning that may have supported these problem-solving abilities. The 21 vocal-learning species had slightly larger brains, relative to their body size, than the two who weren’t. Jarvis says it’s possible these big-headed birds packed more neurons.
One question left unanswered is why there’s such a strong relationship between problem-solving abilities and vocal learning. The brain areas in charge of vocal learning are not the same ones that get activated when we need to troubleshoot an issue, says Jarvis.
【小题1】The purpose of the first paragraph is to ______.| A．promote a new theory | B．offer an example |
| C．present an assumption | D．make a contrast |
| A．To examine the problem-solving ability of songbirds. |
| B．To prove the significance of vocal learning to humans. |
| C．To illustrate the influence of brain size on vocal learning. |
| D．To test the relation between vocal learning and intelligence. |
| A．Advanced species have better problem-solving ability. |
| B．Vocal learners have a better development of intelligence. |
| C．Better problem-solving ability leads to bigger brain size. |
| D．Humans and songbirds are both good at vocal learning. |
| A．why humans’ problem-solving abilities develop better |
| B．how other abilities are connected to songbirds’ intelligence |
| C．how problem-solving and vocal learning brain areas are related |
| D．why vocal learning differences exist in various songbirds species |
