9

Language and Thought

AN ENGLISH BOY NAMED CHRISTOPHER SHOWED an amazing talent for languages. By the age of 6, he had learned French from his sister’s school-books; he acquired Greek from a textbook in only 3 months. His talent was so prodigious that grown-up Christopher could converse fluently in 16 languages. When tested on English–French translations, he scored as well as a native French speaker. Presented with a made-up language, he figured out the complex rules easily, even though advanced language students found them virtually impossible to decipher (Smith & Tsimpli, 1995).

If you have concluded that Christopher is extremely smart, perhaps even a genius, you are wrong. His scores on standard intelligence tests are far below normal. He fails simple cognitive tests that 4-year-old children pass with ease, and he cannot even learn the rules for simple games like tic-tac-toe. Despite his dazzling talent, Christopher lives in a halfway house because he does not have the cognitive capacity to make decisions, reason, or solve problems in a way that would allow him to live independently.

CHRISTOPHER’S STRENGTHS AND WEAKNESSES OFFER COMPELLING EVIDENCE that cognition is composed of distinct abilities. People who learn languages with lightning speed are not necessarily gifted at decision making or problem solving. People who excel at reasoning may have no special ability to master languages. In this chapter, you will learn about five key higher cognitive functions: acquiring and using language, forming concepts and categories, making decisions, solving problems, and reasoning. We excel at these functions compared with other animals, and they help define who we are as a species. We will learn about each of these abilities by examining evidence that reveals their unique psychological characteristics, and we will learn about their distinct neural underpinnings by considering individuals with brain lesions as well as neuroimaging studies. But despite clear differences among them, these five cognitive abilities share something important in common: They are critical to our functioning in just about all aspects of our everyday existence—including work, school, and personal relationships—and as we have already seen with Christopher, impairment of these cognitive abilities can result in major and lasting disruptions to our lives.