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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 evidence that the 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, some psychologists saw no purpose in studying the brain. An influential cognitive scientist, Allen Newell, argued in the 1970s that brain science was irrelevant to psychology.

Newell 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 hardware inside the computer? Why bother studying the brain?

During the 1980s, different opinions became more common. Research on the brain blossomed and cognitive psychologists started using brain scanning in combination with other techniques.

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 resulting activity could be seen on a computer. Inevitably, this led to many new ideas about the information processing in the brain.

By the early decades of the 21st Century, collaboration between psychologists and neuroscientists was not only acceptable; it was one of the most common types of research in experimental psychology.

Contrary to what Newell assumed two decades earlier, studying the "hardware" produced insights into how the system generated its performances. 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.

However, students said they were better able to appreciate the information about neurons after learning about the system as a whole. Now we start with the nervous system and work down to 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 implicated in mental illness are described in Chapter 12 (Abnormal). Mind/body interactions are 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 biological influences on sexual behavior.

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