8

Thinking, Language, and Intelligence

Throughout history, we humans have celebrated our wisdom and bemoaned our foolishness. In this book we likewise marvel at both our abilities and our errors. As our brain develops, our mind blossoms. We move from the amazing abilities of the newborn, to the logic of adolescence, to the wisdom of older age. Our sensory systems gather countless sensations, convert them into nerve impulses, and send them to multiple brain sites, forming meaningful perceptions. Meanwhile, our two-track mind is processing, interpreting, and storing vast amounts of information, with and without our awareness. Not bad for the cabbage-sized three pounds of wet tissue jammed inside our skull.

Yet we are also sometimes simple-minded or error-prone. Our species is kin to the other animals, influenced by the same principles that produce learning in rats, pigeons, and even slugs. Sometimes our thinking fails us. We not-so-wise humans are easily fooled by perceptual illusions, fake psychic claims, and false memories.

In this chapter, we find more examples of these two images—the rational and irrational human. We will consider thinking, and how we use—and sometimes ignore or misuse—information about the world around us. We will look at our gift for language and why and how it develops. And we will reflect on intelligence. How deserving are we of the meaning of our species’ name, Homo sapiens—wise human?