Chapter Two:
The Human Nervous System

Table of Contents

Part One:The Brain

Part Two: Neuropsychology

Part Three: Neurons


Overview of Chapter 2: The Human Nervous System

In this chapter, our integrative theme for the whole book—the creative brain—takes center stage. Here we see the evidence for the truism, "Mind is what the brain does." For example, we see how injuries can disturb mental functioning and how direct brain stimulation can produce mental events.

Prior to the 1980s, many psychologists saw no purpose in studying the brain. An influential cognitive scientist, Allen Newell, probably spoke for many psychologists when he argued in the 1970s that brain science was irrelevant to psychology. He made a simple analogy to computers and their programs. Identical-looking programs can run on completely different computer platforms, he pointed out. Psychologists were interested in those programs and how they operated. They were interested in performance. Who cared about the hardware inside the computer? Why bother studying the brain?

During the 1980s, a different opinion became more common. As research on the brain blossomed, cognitive psychologists found clever ways to use brain scanning and other neuroscience techniques in their own experiments. Also, the zeitgeist (cultural atmosphere) changed. Brain science made so many strides during the 1980s that the United States Congress declared the 1990s "the decade of the brain" in optimistic anticipation of further advances. One important advance was the spread of brain scanning techniques such as functional MRI (fMRI). Functional MRI allowed researchers to pinpoint small areas of rapid activity in the brain. Researchers could ask a subject to do something, or think something, and the resulting activity could be seen on a computer. Inevitably, this led to many new ideas about the information processing in the brain.

By the decade of the 2000s, collaboration between psychologists and neuroscientists was not only acceptable; it was one of the hottest types of research in experimental psychology. Contrary to what Newell predicted two decades earlier, studying the "hardware" frequently produced insights into how the system produced its performances. Studying the brain gave psychologists new ideas and had a big impact on the field. In fact, you will notice references to brain scanning evidence in almost every chapter of this book.

How this Chapter is Organized

We start with a look at the brain as a whole, including its relation to the peripheral nervous system and endocrine system. Then we review some classic findings from neuropsychology, the study of brain injury and brain/behavior relations. Finally, we discuss the neuron or brain cell.

Why are the subjects discussed in this order? It was not always so. Originally this chapter started with the small components (neurons) and worked up to the system as a whole. But students said they were better able to appreciate the information about neurons after learning about the system as a whole, so now we start with the nervous system and work down to a discussion of its components at the end of the chapter.

Related Topics in Other Chapters

Some speculations about brain mechanisms of consciousness are in Chapter 3 (States of Consciousness). Sensory mechanisms are discussed in Chapter 4 (Senses and Perception). The effect of learning on biological processes is in Chapter 5 (Conditioning). Biological mechanisms of memory are in Chapter 6 (Memory); modern views of instinctive behavior are discussed in Chapter 8 (Animal Behavior and Cognition); biological approaches to motivation are in Chapter 9 (Motivation).

Genetic influences and theories of aging are in Chapter 10 (Development) and brain transmitters involved in mental illness are mentioned throughout Chapter 12 (Abnormal). Mind/body interactions and the nature of "stress" is discussed in Chapter 14 (Frontiers of Psychology). Chapter 15 (Social Psychology) mentions the role of hormones and brain transmitters in aggressive behavior, and Chapter 16 (Sex, Friendship and Love) discusses some biological influences on sexual behavior.


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