Chapter Introduction

JENNIFER, A 45-YEAR-OLD CAREER MILITARY NURSE, lived quietly in a rural area of the United States with her spouse of 21 years and their two children before she served 19 months abroad during the Iraq war. In Iraq, she provided care to American and international soldiers as well as to Iraqi civilians, prisoners, and militant extremists.

Jennifer served 4 months of her assignment in a hospital near Baghdad, where she witnessed many horrifying events. The prison was the target of relentless mortar fire, resulting in numerous deaths and serious casualties, including bloody injuries and loss of limbs. Jennifer worked 12- to 14-hour shifts, trying to avoid incoming fire while tending to some of the most gruesomely wounded cases. She frequently encountered the smell of burnt flesh and the sight of “young, mangled bodies” as part of her daily duties (Feczer & Bjorklund, 2009, p. 285).

This repetitive trauma took a toll on Jennifer, and when she returned home, it became evident that she had not left behind her war experiences. Jennifer thought about them repeatedly and they profoundly influenced her reactions to many aspects of everyday life. The sight of blood or the smell of cooking meat made her sick to her stomach, to the point that she had to stop eating meat. The previously innocent sound of a helicopter approaching, which in Iraq signaled that new wounded bodies were about to arrive, now created in Jennifer heightened feelings of fear and anxiety. She regularly awoke from nightmares concerning the most troubling aspects of her Iraq experiences, such as tending to soldiers with multiple amputations. In the words of the authors who described her case, Jennifer was “forever changed” by her Iraq experiences (Feczer & Bjorklund, 2009). And that is one reason why Jennifer’s story is a compelling, though disturbing, introduction to the topic of learning.

Much of what happened to Jennifer after she returned home reflects the operation of a kind of learning based on association. Sights, sounds, and smells in Iraq had become associated with negative emotions in a way that created an enduring bond, so that encountering similar sights, sounds, and smells at home elicited similarly intense negative feelings.

During the 4 months that she served at a prison hospital near Baghdad during the Iraq war, Jennifer learned to associate the sound of an arriving helicopter with wounded bodies. That learned association had a long-lasting influence on her.

AP PHOTO/JOHN MOORE

How might psychologists use the concept of habituation to explain the fact that today’s action movies tend to show much more graphic violence than movies of the 1980s, which in turn tended to show more graphic violence than movies of the 1950s?

PARAMOUNT PICTURES/THE KOBAL COLLECTION

LEARNING IS SHORTHAND FOR A COLLECTION OF DIFFERENT TECHNIQUES, procedures, and outcomes that produce changes in an organism’s behavior. Learning psychologists have identified and studied as many as 40 different kinds of learning. However, there is a basic principle at the core of all of them. Learning involves the acquisition of new knowledge, skills, or responses from experience that results in a relatively permanent change in the state of the learner. This definition emphasizes these key ideas:

• Learning is based on experience.
• Learning produces changes in the organism.
• These changes are relatively permanent.

Think about Jennifer’s time in Iraq and you’ll see all of these elements: Experiences such as the association between the sound of an approaching helicopter and the arrival of wounded bodies changed the way Jennifer responded to certain situations in a way that lasted for years.

Learning can also occur in much simpler, nonassociative forms. You are probably familiar with the phenomenon of habituation, a general process in which repeated or prolonged exposure to a stimulus results in a gradual reduction in responding. If you’ve ever lived under the flight path of your local airport, near railroad tracks, or by a busy highway, you’ve probably noticed the deafening roar as a Boeing 737 made its way toward the landing strip, the clatter of a train speeding down the track, or the sound of traffic when you first moved in. You probably also noticed that, after a while, the roar wasn’t quite so deafening anymore and that eventually you ignored the sounds of the planes, trains, or automobiles in your vicinity. This welcome reduction in responding reflects the operation of habituation.

Habituation occurs even in the simplest organisms. For example, in the Memory chapter you learned about the sea slug Aplysia, studied in detail by Nobel Prize winner Eric Kandel (2006). Kandel and his colleagues showed clearly that Aplysia exhibits habituation: When lightly touched, the sea slug initially withdraws its gill, but the response gradually weakens after repeated light touches. In addition, Aplysia also exhibits another simple form of learning known as sensitization, which occurs when presentation of a stimulus leads to an increased response to a later stimulus. For example, Kandel found that after receiving a strong shock, Aplysia showed an increased gill withdrawal response to a light touch. In a similar manner, people whose houses have been broken into may later become hypersensitive to late-night sounds that wouldn’t have bothered them previously.

Although these simple kinds of learning are important, in this chapter we’ll focus on more complex kinds of learning that psychologists have studied intensively. As you’ll recall from the Psychology: Evolution of a Science chapter, a sizable chunk of psychology’s history was devoted to behaviorism, with its insistence on measuring only observable, quantifiable behavior and its dismissal of mental activity as irrelevant and unknowable. Behaviorism was the major outlook of most psychologists working from the 1930s through the 1950s, the period during which most of the fundamental work on learning theory took place.

You might find the intersection of behaviorism and learning theory a bit surprising. After all, at one level learning seems abstract: Something intangible happens to you, and you think or behave differently thereafter. It seems logical that you’d need to explain that transformation in terms of a change in mental outlook. However, most behaviorists argued that learning’s “permanent change in experience” could be demonstrated equally well in almost any organism: rats, dogs, pigeons, mice, pigs, or humans. From this perspective, behaviorists viewed learning as a purely behavioral activity requiring no mental activity.

In many ways the behaviorists were right. Much of what we know about how organisms learn comes directly from the behaviorists’ observations of behaviors. However, they also overstated their case. There are some important cognitive considerations (i.e., elements of mental activity) that need to be addressed in order to understand the learning process. In the first two sections of this chapter, we’ll discuss the development and basic principles of two major approaches to learning: classical conditioning and operant conditioning. We’ll then move on to see that some important kinds of learning occur simply by watching others, and that such observational learning plays an important role in the cultural transmission of behavior. Next, we’ll discover that some kinds of learning can occur entirely outside of awareness. Finally, we’ll discuss learning in a context that should matter a lot to you: the classroom.