Unlearned Adaptive Behaviors
Module 03 Reading
CHAPTER 3
SOME BASICS: ELICITED BEHAVIORS,
HABITUATION, AND OPPONENT-PROCESS THEORY OF EMOTIONS
CHAPTER OUTLINE
Elicited Behaviors
Reflexes
Tropisms
Fixed Action Patterns/Modal Action Patterns
Check Your Learning
Habituation and Sensitization
Habituation
Sensitization
General Characteristics
The Dual-Process Theory
Check Your Learning
Opponent-Process Theory of Emotions
Defining Emotion
Emotion and Evolution
The Opponent-Process Theory
Motivation
Extinction
Check Your Learning
Drug Addiction: The Opponent-Process Theory in the Real World
As you saw in Chapter 1, the definition of learning includes such concepts as (a) a relatively permanent change in behavior or behavior potential, and (b) experience. Our definition of learning included these concepts in order to distinguish learning from other types of behavior change. Maturation is a good example of a change in behavior that we would not classify as learning. When you were 6 months old you were not able to walk. However, by the time you were a year old you likely were walking. Did this change in behavior occur as a result of learning? No. Your newly developed ability to walk reflects the maturation of your muscles to the point that you were physically able to perform this behavior.
Elicited Behaviors
In addition to maturation, there are other changes in behavior that can be mistaken for learning. Among these processes are reflexes, tropisms, fixes action patterns, habituation, emotions,motivation, and extinction. As you will see in the following pages, even though these processes are not examples of learning, in many instances they are involved in and can influence the learning processes.
Reflexes
A reflex is an innate process that is elicited by a specific stimulus. As you can see in Figure 3-1, the simplest reflex has three components:
- An afferent (sensory) neuron that sends a sensory message to the spinal cord.
- An interneuron that relays the sensory message to
- An efferent (motor) neuron that activates the muscles that produce the reflexive response.
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Fig. 3-1 Goes Here
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- Humans and nonhuman animals possess a large number of reflexes. For example, the startle response is a reflexive response to a loud noise. Likewise, if you are barefoot and step on a piece of broken glass, you will reflexively lift your foot. Reflexes occur very rapidly; for example, the reflexive response to a painful stimulus, such as stepping on broken glass, occurs in about 0.80 milliseconds (1 millisecond = 1/1000 second) (Goodenough, McGuire, & Wallace, 2005). Table 3-1 lists several common reflexes.
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Table 3-1. Several Common Reflexes.
- Leg-Flexion Reflex – A painful stimulus delivered to the leg will cause the leg to flex.
- Investigatory Reflex – A novel or unexpected stimulus elicits inspection and investigatory behaviors.
- Babinski Reflex – When the sole of an infant’s foot is stimulated, the toes fan out.
- Plantar Reflex – Contraction of the toes when the sole of the foot is lightly stroked; replaces the Babinski reflex.
- Moro Reflex – A startle-like response that occurs when an infant experiences sudden motion or hears a loud noise.
- Rooting Reflex – Rubbing a finger (or similar stimulus) along an infant’s cheek causes the infant to turn its head in the direction of the stimulated cheek and to begin to make sucking motions.
- Grasp Reflex – Stimulation of an infant’s palm will cause the infant to close its hand tightly around the stimulating object.
- Pupillary Reflex – A painful or emotional stimulus causes the pupil of the eye to dilate.
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- Without question, reflexes assist organisms in adapting to their respective environments. The startle response heightens your awareness of the stimuli around you. The sucking reflex, which is initiated by putting an object in the mouth, is crucial for feeding.
At one time, John B. Watson, the noted behaviorist, believed that was important to catalog all our reflexes. He asserted that if we knew and understood all the reflexes, then those behaviors that were not reflexes would belong to the “learned” category. Although psychologists abandoned this view many years ago, reflexes still play an important role and their study has been an integral component of the psychology of learning for decades. As you will see in the next chapter, the basic learning process known as classical or Pavlovian conditioning is based on the procedure of converting a neutral stimulus into a conditioned stimulus that is capable of eliciting a response that originally occurred reflexively. Because reflexes have always been an integral component of classical conditioning, a considerable amount of the early research on this topic sought to investigate as many reflexes as possible and determine those that were most (and least) conditionable (Kimble, 1961). Even though this line of research no longer commands a high priority in research laboratories, reflexes continue to be important to the study of basic processes of learning, Early researchers also were quick to begin investigating another reflex-like behavior, tropisms.
Tropisms
Whereas reflexes involve the movement of one part of the body, such as blinking when a puff of air strikes your eye, a tropism involves movement of the entire body. Moreover, tropisms are forced by a particular environmental stimulus.
Jacques Loeb (1859-1924), a German zoologist and physiologist, who taught at Bryn Mawr College, the University of Chicago, the University of California, and the Rockefeller Institute (see Boring, 1950), originated the concept of tropisms in 1890. The theory was translated into English in 1900 (Loeb, 1900). In his theory of tropisms, Loeb indicated that both animals and plants display this behavior. For example, if you have ever seen sunflowers and noticed that that they always are facing the sun, then you have witnessed a positive heliotropism. The sun’s light forces these plants to follow it. An example of a tropism shown by an animal would be the seeking of a humid, moist environment by the wood louse (Fraenkle & Gunn, 1940).
Tropisms and their study were important to numerous early American psychologists, such as John B. Watson who Jacques Loeb’s student at the University of Chicago, because they represented a mechanistic way to understand behavior. According to Goodwin (1999), “Loeb was an uncompromising materialist and mechanist who believed that all organic life could be understood as a series of automatic responses to stimuli” (p. 302). Thus, in addition to being sympathetic to Loeb’s mechanistic view, Watson reasoned that a listing of tropisms for a species would supplement the list of of reflexes and assist in isolating those behaviors that were learned.
Fixed Action Patterns/Modal Action Patterns
Regardless of whether you use the older term, fixed action pattern (Eibl-Eibesfeldt, 1975), or the more recent term, modal action pattern (Baerends, 1988), you are dealing with a response sequence that is elicited rather than learned. These response sequences were originally studied by European ethologists, such as Lorenz (1952) and Tinbergen (1951). Ethology is the study of the behavior of animals in their natural environment.
The ethologists called these response sequences fixed action patterns because when they were elicited they appeared to be displayed in exactly the same manner by all members of the species. In other words, they were “fixed” and did vary. Continued study has indicated that there is some variability in these behaviors; hence, many researchers now use the term modal action pattern (Baerends, 1988). Because modal action patterns are unlearned, they definitely belong in the category of instinctive behaviors.
**** Now that you know what a modal action pattern is, it is time to turn our attention to what elicits them. Write down some possibilities before reading further.
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If you noticed a parallel between modal action patterns and simple reflexes, give yourself a pat on the back. Just as a specific stimulus elicits a reflex, a special, specific stimulus elicits a modal action pattern. This stimulus, called a sign stimulus, can be a specific feature of the environment or even another animal. You will see examples of both types of sign stimuli in the following classic research example.
Perhaps the most widely known study of a modal action pattern involved a small fish, the three-spined stickleback (Tinbergen, 1951). During mating season both male and female sticklebacks engage in a series of complex and interrelated behaviors. The interrelatedness of these behaviors clearly shows that environmental and physiological conditions must be right before modal action patters are elicited. Let’s examine these interrelated behaviors more closely. First, the physiological changes that characterize the breeding season must be present for both male and female fish. Once the physiological conditions are appropriate, the male stickleback stakes out a territory, which he will defend vigorously against other male intruders. Then he builds a nest. Only after he has built the nest will the male stickleback court the female. When a female enters the territory containing the nest, the male begins a side-to-side, wig-wag swimming pattern or courtship dance to entice the female to swim through the nest. In turn, swimming through the nest stimulates the female stickleback to lay her eggs. Once the female has laid the eggs, the male will drive her off, fertilize the eggs, and defend his territory. Certainly, several sign stimuli were present and reacted to in the behaviors that we just considered. For example, the swollen belly of the female stickleback who is about to lay her eggs is a sign stimulus for the courtship swim by the male that entices her to swim through the nest. The sign stimulus for territorial defense is one of the most interesting and well researched. Tinbergen (1951) and his colleagues wondered exactly what it was about another male stickleback that would elicit the stereotyped head-down threat posture that characterizes territorial defense. After examining several aspects of the male fish that might serve as a sign stimulus, they found that the bright red spot on the male’s belly was a crucial cue.
**** Here’s a chance for you to put yourself in the researchers’ position. How did they conclusively determine that the red spot was the crucial, cue? Develop an answer before you read further.
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After noting that models of fish with the red spot elicited defensive behavior, whereas models without the spot did not, the crucial test was to paint over the red spot on a live fish. If the test fish failed to elicit a defensive reaction when the red spot was covered, but elicited the reaction when the spot was visible, then a strong case could be made for the red spot being the sign stimulus. This was the result that Tinbergen found.
Even though we have discussed them separately, you should not get the idea that reflexes and modal action patterns occur independently of each other; they can, and do, occur together. Reflexes may serve to bring an animal into close proximity to a sign stimulus, which, in turn, elicits a modal action pattern. For example, the sight of a herring gull parent may cause a hungry chick to reflexively orient toward the parent. Once oriented, certain stimulus cues of the parent serve as sign stimuli for the chick. For example, researchers have determined that a bright red spot on the parent’s bill is the sign stimulus pecking by the chicks. In turn, when herring gull chicks peck at the red spot on the parent’s bill, this behavior causes the parent to regurgitate and provide food for the chicks. Clearly, reflexes and modal action patterns can combine to form an impressive sequence of behavior.
As we have noted, whether they are reflexes, tropisms, or modal action patterns, behaviors that are elicited are not learned behaviors. There are other forms of behavior change that also do not qualify as learned responses. We turn to two of these behaviors, habituation and sensitization, next.
Habituation and Sensitization
When we consider habituation and sensitization, we are dealing with the effects of repeated presentations of a stimulus. Habituation occurs when repeated presentations of a stimulus result in a decrease in the strength of the elicited response. Sensitization occurs when repeated presentation of a stimulus results in an increase in the strength of subsequent elicited responses. It is important to remember that even though these processes result in behavioral change, they do not represent true instances of learned behavior. Let’s see what researchers have learned about these processes.
Habituation
Researchers have studied habituation very extensively in Aplysia, a marine snail that has a relatively simple and easy to study nervous system. Aplysia feeds on seaweed on the ocean floor. Water and nutrients enter through the gill and water and waste are expelled through the siphon (see Figure 3-2). Touching the siphon causes the siphon and gill to reflexively withdraw
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Figure 3-2 Goes Here
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under the cover of a protective mantle. Carew, Pinsker, and Kandel (1972) reported that a touch to the siphon every 30 seconds resulted in the gradual decline in strength of the gill-withdrawal reflex. Following a session during which the researchers made as few as 10 gill touches, habituation can last as long as 2 to 3 hours.
The study of habituation of the gill-withdrawal reflex in Aplysia is important because the relatively simple nervous system of this organism makes it more accessible to study. Researchers have isolated the specific neurons involved in this instance of habituation and have studied the activity of these neurons as habituation occurred. Without question, research of this type has furthered our understanding of neuronal functioning in a variety of organisms. For example, Davis (1989) traced the neural pathway involved in habituation of the startle response in the rat. Likewise, modern brain-imaging techniques (see Anderson, 2008), such as functional magnetic resonance imaging (fMRI), have enabled researchers to identify areas of the human brain that are active during habituation. The pattern that appears to be emerging from these studies of the human brain is that many different areas of the brain are involved in habituation, and, moreover, that different areas are active when habituation occurs in different sensory modalities.
If you have been wondering about the occurrence of habituation in humans, the answer is an unqualified yes—it does occur in humans, if not all organisms. For example, what would your response be if a loud noise unexpectedly sounded behind you? Most likely you would display a startle reflex. Now, what would happen to your startle reflex if the same loud noise was repeatedly sounded several times? Most likely, the startle reflex would gradually decrease in strength with each repetition of the sound. Before you confidently say that this is a clear example of habituation, we need rule out another possible explanation for the decrease in your startle reflex. This alternative explanation involves adaptation. Similar to habituation, adaptation is a decrease in sensation that results from repeated presentation of a stimulus. Unlike habituation, however, adaptation appears to occur from receptor fatigue;the receptors simply cease to function in a normal, respo0nsive manner..
**** Here’s a situation that should challenge your critical thinking ability. How could a researcher demonstrate that the decrease in a startle response was due to habituation and not adaptation? Write down a possible procedure before you read further.
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Actually, it is relatively easy to make this test; all you have to do is change to a different auditory stimulus. If habituation has occurred, then changing to a different auditory stimulus should result in a recovery of the startle response. However, if adaptation has occurred, then changing from one auditory stimulus to another should result in a very minimal, if any, startle response.
Want to experience habituation first-hand? Here’s how you and your friends can conduct an habituation exercise. To conduct this session you will need a lemon, a lime, a box of toothpicks, and a pencil and paper. First, separately squeeze the lemon and lime; keep the juice in two small bowls (be sure you know which is which). To conduct a trial, dip a clean toothpick in one of the bowls and place a small amount (e.g., one drop) of juice on the participant’s tongue. The participant then gives a hedonic (pleasantness) rating of the taste. Make sure that you use the same rating scale from one trial to the next. For example, you might use a 1 (worst I’ve ever tasted) to 10 (best I’ve ever tasted) scale. Be sure you identify each rating by the trial number on which it occurred. After your participant has experienced the taste and made the rating, wait 15 seconds and then administer another trial in exactly the same manner. You will conduct 10 trials with one flavor; on the 11th trial switch to the other flavor. You should notice a decrease in hedonic ratings from Trial 1 to Trial 10. This decline is due to habituation. However, when you shift flavors on Trial 11, the rating should increase noticeably due to the change in flavors. Epstein, Rodfer, Wisnewski, and Caggiula (1992) conducted this procedure under controlled, laboratory conditions and found this pattern of results for both hedonic ratings and salivation.
Sensitization
As we mentioned, sensitization occurs when the repeated presentation of a stimulus results in an increase in the strength of subsequent, elicited responses. Most likely, a noxious stimulus will be the cause of sensitization. Let’s return to the sea snail, Aplysia, for an example of sensitization. If an experimenter administers a mild electric shock to the Aplysia’s tail (see Figure 3-2), then the sensitivity of the gill-withdrawal response is increased; thus, lighter-than-normal touches to the siphon are able to produce this response (Carew, Castellucci, & Kandel, 1971). Depending on the number of shocks that the experimenter administers, this sensitization can last from a few minutes (single shock) to several days (series of shocks) (Pinsker, Hening, Carew, & Kandel, 1973). The simplicity and accessibility of Aplysia’s nervous system again allowed researchers to isolate the neural circuitry and mechanism that is responsible for sensitization. More specifically, Castellucci and Kandel (1976) demonstrated that sensitization in Aplysia is attributable to an increase in the release of a neurotransmitter. These results have assisted researchers in understanding the operation of sensitization in other organisms.
General Characteristics
Dating from the research of Thompson and Spencer (1966), researchers have noted that habituation and sensitization are similar in certain respects, but not others.
Duration of the Effect. Whereas phenomena included in the category of learned behaviors typically last for an extended period of time (e.g., weeks, months, or years), habituation and sensitization are not long lasting. Recall that sensitization in Aplysia following a series of shocks to the tail lasted only several days. Other sensitization effects can be as short as 3 seconds (Groves & Thompson, 1970). Likewise, the duration of habituation also can last from a few seconds to several days (Leaton, 1976; Thompson & Spencer, 1966). These more limited durations serve to distinguish habituation and sensitization from true examples of leaning.
Stimulus Specificity and Generalization. If you conducted the lemon and lime exercise we described above, you already know that habituation is very stimulus specific. That is, even though habituation is shown to one stimulus, it will not be shown to a stimulus that differs along a relevant dimension. Although lemons and limes are both citrus tastes, they differ sufficiently to keep habituation to one taste from generalizing to the other taste. The stimuli must be very similar for habituation to generalize.
Sensitization, however, is a different matter; it is not stimulus specific and generalizes widely. Generalization of sensitization may even occur across sensory modalities. Thus, it would appear that experiencing one type of noxious stimulus sensitizes us to other noxious stimuli.
Stimulus Intensity. Although there may be exceptions, habituation and sensitization occur most strongly with weaker stimuli.
The Dual-Process Theory
We have seen that habituation does not reflect the operation of sensory adaptation; the receptors do not lose their ability to process stimulation. Likewise, habituation does not occur because of muscle fatigue.
**** Give these statements some thought, review Figure 3-1, and then propose what portion of the reflex a theory of habituation and sensitization will focus its attention on and why you have made this choice.
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When you looked at Figure 3-1, you likely noticed that these statements ruled out two components of the reflex: afferent (sensory) neurons and efferent (motor) neurons. Hence, a theoretical account of habituation and sensitization will have to focus on interneurons and their interface with the sensory and motor neurons.
The dual-process theory proposed by Groves and Thompson (1970; see also Thompson, Groves, Teyler, & Roemer, 1973) takes full advantage of this logical analysis and focuses its attention on the largest group of interneurons, the brain. Even though this theory was developed over four decades ago, it continues to be the dominant theory in this area. Groves and Thompson’s basic assumption is that when a stimulus is presented, the potential exists for both habituation and sensitization to occur: hence, the name dual-process theory. Yes, the presentation of a single stimulus can elicit both processes. For example, a loud noise may elicit a startle response that decreases with multiple presentations of the stimulus (habituation). That same loud noise may also increase the organism’s responsiveness to other stimuli (sensitization).
The next issue to be dealt with is which process will manifest itself as a behavioral response. The answer, according to Groves and Thompson (1970), is really quite straight forward; the stronger process will determine the behavioral outcome. If sensitization is stronger than habituation, then this process will dominate; if habituation is stronger than sensitization, then it will dominate. Mathematically, this principle is analogous to adding positive and negative numbers; the net outcome is the sum of these two numbers. For example:
-4 added to +6 equals +2
-11 added to +4 equals -7
-8 added to +8 equals 0
If you want to consider that positive numbers reflect sensitization and that negative numbers reflect habituation, then weak sensitization will be shown in the first example because the result is a small positive number. Stronger habituation will dominate in the second example because the result is a larger negative number; whereas, when the result is 0 neither sensitization nor habituation will be the dominant response. Figure 3-3 illustrates these three situations graphically.
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Figure 3-3 Goes Here
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As we will see in the next section, the dual-process theory provides research support that parallels an interesting theory of emotional responding.
Check Your Learning
Because they involve behavior change, elicited behaviors can be mistaken for examples of true learning.
A reflex is an innate process that is elicited by a specific stimulus.
A tropism is a behavior that is forced by a particular stimulus.
A fixed action pattern/modal action pattern is an elicited, stereotyped response sequence that all members of a species display.
Habituation occurs when repeated presentations of a stimulus result in a decrease in the strength of the elicited response.
Sensitization occurs when repeated presentation of a stimulus results in an increase in the strength of subsequent elicited responses.
The dual-process theory states that the respective strengths of sensitization and habituation combine. The net value of this combination determines whether the dominant response will be habituation or sensitization.
Opponent-Process Theory of Emotions
“There is no way that someone could convince me to sky-dive!” Those were your thoughts before your friends persuaded you to try it. The fear and anxiety that you felt before and during that first jump were almost unbearable. Once you were safely on the ground the feelings of fear and anxiety were replaced by a feeling of mild elation and euphoria. Perhaps the experience was not so bad after all. A dozen jumps later, the intense fear you initially experienced is now just mild anxiety, and the euphoria that you experience after the jump has increased dramatically. Clearly emotional responses occurred during these episodes. However, there is a great deal more that we can learn about emotion from this sequence of events. However, before we look at the sky-diving example more closely, we need to examine the term emotion and define exactly what we mean when we use it.
Defining Emotion
You may remember from your introductory psychology course that even though emotions are commonplace occurrences in our daily live, defining them was more difficult. In fact, during the Twentieth Century over 90 definitions of emotion appeared in the literature (Plutchik, 2001). This difficulty occurs because emotions actually are a combination of several different processes. For example, emotions involve physiological changes, such as increased heart rate, tensed muscles, and increased respiratory rate (i.e., changes in the parasympathetic division of the autonomic nervous system).
**** We can add another dimension to our definition of emotions by asking the question “What elicits an emotion?” Give this question some thought and write down your answer(s) before you read further.
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If you indicated that some type of cue or stimulus elicits an emotion, then you are correct. For example, the sound of footsteps behind you on a deserted street late at night may elicit fear; the sight of a beautiful sunrise or sunset might elicit awe or feelings of ecstacy. However, we cannot simply indicate that a stimulus elicits an emotion, we need to expand our consideration of the nature of the stimulus in order to be complete. What more is there to add about the stimulus? If you stop and think about the emotional stimulus, you likely will realize that there are two basic types: stimuli that are received from the environment by our sense organs are external stimuli, whereas stimuli that are produced by the nervous system and internal organs are internal stimuli. The footsteps you heard on the deserted street and the sight of a beautiful sunset are examples of external stimuli fear. The thought of a pleasant experience you have had in the past is an internal stimulus that is likely to elicit an emotion. Thus, the stimulus that elicits the emotion is a second factor that is involved in emotional behavior.
By also noting that an emotion can have behavioral consequences, we add yet another dimension to our definition (Palladino & Bloom, 2008). An example of a behavioral outcome of an emotion would be your increased pace of walking that occurred after you hear footsteps behind you on the dark street late at night.
In summary, we have seen that an emotional response is a composite of four main components: (a) physiological changes that occur primarily in the parasympathetic division of the autonomic nervous system, (b) the presence of an external or internal eliciting stimulus, (c) feelings of pleasantness or unpleasantness, and (d) the potential for a behavioral reaction. Putting these components together, we can tentatively define emotions as physiological changes and conscious feelings of pleasantness or unpleasantness, aroused by external or internal stimuli, that lead to behavioral reactions. It is important to keep in mind that emotional reactions can, and do, result in behavioral changes. As you will see in subsequent chapters, learning may be a component of some emotional reactions.
Emotion and Evolution
Dating from Darwin’s The expression of emotion in man and animals (1872/1965), researchers have contended that emotions play a role in adaptation to the environment and, therefore, may be evolutionarily determined. For example, research has shown that facial expressions of emotions are universal and even occur in infants born blind and deaf (Galati, Scherer, & Ricci-Bitti, 1997). By showing photographs to people around the world and asking them to identify the emotion depicted, Ekman (2003) has identified six emotions that appear to be recognized everywhere: anger, disgust, fear, happiness, sadness, and surprise. Thus, it would appear that emotional display and recognition is a trait that is passed from one generation to the next.
**** It is one thing to indicate that emotional display and recognition may be genetically transmitted, it is definitely a different task to indicate the role of these processes in helping an organism adapt to the environment. What are some of the adaptive functions that emotions can serve? Write down some possibilities and then read further.
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Basically, emotions increase the chance of survival by providing a readiness for action (Plutchik, 2001). Anger is a good example: It “intimidates, influences others to do something you wish them to do, energizes an individual for attack or defense and spaces the participants in a conflict” (Plutchik, 2001, p. 348). Likewise, fear quickly drives blood to the large muscles, making it easier to run. When we are surprised, we raise our eyebrows; this response allows the eyes to collect more information.
Yes, emotions can facilitate adaptation to the environment. The only problem is that our fast-paced society has changed to such a great extent that the need for such emotions is no longer as crucial as it was in previous generations. On the other hand, evolutionary change has yet to catch up with societal changes. Hence, emotions, such as anger, that prepare us for flight or flight may be counterproductive.
Given this general background on emotional responding, it is time to return to our sky-diving scenario and the opponent-process theory of emotion.
The Opponent-Process Theory
The opponent-process theory of emotion proposed by Richard Solomon and his colleagues (Solomon, 1980, 1982; Solomon & Corbit, 1974) is similar to the processes of habituation and sensitization. The basic premise is that repeated presentations of an emotional stimulus are sufficient to change a person’s reaction to that stimulus. However, the changes in a person’s reactions are not random; they involve a definite sequence that has two components. First, there is the initial emotional reaction. For example, this reaction would be the fear that you experience when you go sky-diving. The second component is the aftereffect, which you can think of as a reaction to a reaction. In our sky-diving example, the feeling of euphoria that you experienced when you returned safely to the ground is the aftereffect; the aftereffect typically is the opposite of the initial emotional reaction. Solomon and Corbit labeled the initial response as the a-process, whereas the aftereffect or reaction to the reaction was the b-process. For example, a person who takes amphetamine will initially experience a “rush” and have feelings of euphoria (a-process); however, when the effects of the drug have worn off, the euphoric feelings will be replaced by feelings of depression and tiredness.
**** Even though you likely can relate to the fact that one emotion is frequently followed by its opposite, you also may be wondering what triggers the second, opposite effect. Write down some possible causes before reading further.
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The initial reaction, the a-process, is the stimulus for the opposite reaction (b-process). Just as the dual theory assumes that habituation and sensitization serve to produce a net or overall effect (see Figure 3-3), the opponent-process theory assumes that the a-process and b-process combine to produce a net effect,
Moreover, the theory makes some important assumptions about these two processes. For example, the a-process is fast-acting and remains at its maximum level as long as the eliciting stimulus is present. When the eliciting stimulus ends, the a-process decays rapidly. On the other hand, the b-process, which is elicited by the a-process, is slower to develop and slower to decay. Additionally, the b-process becomes strengthened by repeated exposure to the emotional stimulus. More specifically, it occurs sooner, reaches a higher maximum intensity, and decays more slowly. These changes in the b-process that occur with repeated exposure to the emotional stimulus are responsible fore the changes in emotional reaction that we saw in our sky-diving example. The characteristics of the a– and b-processes are summarized in Table 3-2.
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Table 3-2. Characteristics of the a– and b-Processes of the Opponent-Process Theory
a-processes
fast acting
remains at maximum strength as long as the eliciting stimulus is present
decays rapidly when the eliciting stimulus is terminated
b-processes
elicited by the a-process
slower to develop
becomes stronger with repeated presentations of the a-process
occurs sooner with repeated presentations of the a-process
slower to decay
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You need to keep in mind that when we are describing the a-processes and b-processes were are referring to the physiological responses that are the basis for the emotional response that you actually experience. So why did euphoria become the predominant reaction to sky-diving? Let’s see how the a– and b-processes translate into your emotional response.
In Part I of Figure 3-4 we have depicted the general occurrence of the a– and b-processes as they developed on the first presentation of a fear-producing stimulus. As you can see, the a-process develops rapidly when the fear-producing stimulus is presented and decays rapidly when it is terminated. On the other hand, the b-process develops more slowly, has less strength, and decays more slowly. In Part II of Figure 3-4 you can see how these processes combine to produce the
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Figure 3-4 Goes Here
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emotional reaction that you experienced on your first attempt at sky-diving. Because the b-process is slow to develop, you initially experienced great fear and anxiety. As the b-process developed, the fear and anxiety subsided somewhat. Finally, when you safely reached the ground and the fear-producing stimulus (and the a-process) were terminated, the b-process persisted because it decayed more slowly and you experienced mild, temporary euphoria.
Now, let’s examine the nature of the a– and b-processes and their combined effects after several presentations of the fear-producing stimulus. The strength of the two underlying processes is shown in Part I of Figure 3-5; whereas, the experienced emotions produced by their combined effects is shown in Part II of Figure 3-5.
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Figure 3-5 Goes Here
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As you can see in Part I, the a-process still develops rapidly and to its maximum strength when the stimulus is turned off and decays rapidly when the stimulus is turned off. However, due to repeated presentations, he b-process now develops more rapidly and more strongly than it did on the first presentation of the fear-producing stimulus (review Figure 3-4, Part I). The b-process continues to decay more slowly than the a-process. The net result of these changes in he b-process is that the amount of fear that you experience when the fear-producing is turned on is substantially reduced and lasts only briefly. However, the euphoria is stronger and more long lasting.
Motivation
Motivation is a common term that nearly everyone believes they understand; clearly motivation is involved in behavior change. Because it results in behavior change, should we consider motivation as an example of learning? Most researchers and theorists would say no. Part of their reason for excluding motivational changes from the category of learned behavior is found in the definition of motivation. Theorists (e.g., Pintrick, 2003) typically define motivation as an internal process that has three features:
Activation – Motivation acts to energize behavior.
Direction – Motivation directs or guides the organism’s behavior toward a goal.
Maintenance – Motivation maintains the behavior until the desired goal is achieved.
You need to understand that motivation includes both physiological and psychological aspects. Considerable research has been directed toward understanding these two aspects. Before we discuss these two aspects, we need to indicate that motivation is a hypothetical construct; we cannot see or measure it directly. Rather, we infer the existence of motivation from changes in behavior. In this respect motivation and learning are very much alike; they both are hypothetical constructs that we infer from behavioral changes.
**** If motivation and learning are both hypothetical constructs that we infer, what makes them different? Why aren’t changes in behavior due to motivation considered examples of learning? Write down some possibilities before reading further.
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The major factor that distinguishes learning and motivation concerns the time it takes for the behavioral change to take place. When learning is involved, the behavioral change sis gradual and occurs as a result of practice. When a motivational state is created, the change in behavior is much more rapid and does not require practice. For example, Richter (1922) reported that, even though they were tested in the same apparatus each day, the activity level of female rats peaked every 5 days. He also reported that this increase in activity level coincided with the rats’ sexual receptivity (estrus) cycle. In other words, estrus (an internal physiological motivational state) produced an increase in activity. This behavioral change occurred rapidly and when this motivational state dissipated the activity returned to its lower, nonestrus level. Other physiologically based motives include such states as hunger and thirst, and so forth.
Not all motives are physiologically based; as we have noted, some motives psychological. For example, a motivational state known as cognitive dissonance occurs when a person has two incompatible thoughts (Aronson, Wilson, & Akert, 2002). Cognitive dissonance, in turn, produces an internal state of tension or discomfort.
**** Think about the satte of discomfort that the incompatible thoughts produce. Can you describe it more fully and make predictions about its consequences? Write down an answer before you read further.
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The state of tension or discomfort created by the incompatible thoughts is a motivational state. People are motivated to reduce such discomfort and return to a state of cognitive consonance where their thoughts are compatible with each other. If you are familiar with Maslow’s (1970) hierarchy of needs then you may recall that several of these needs, such as belongingness and love needs, esteem needs, and self-actualization, are psychological motives.
To reiterate, the main point we are making is that motives, whether they are physiological or psychological, do result in behavior changes; however these changes do not belong in the category of learned behaviors. That is not to say that motivation does not play an important role in learning; it certainly does. For example, hungry or thirst organisms easily learn responses that bring them food or water, whereas organisms that are not hungry or thirsty do not learn such responses easily.
Trying to understand human motivation brings into consideration issues that take the researcher far afield from basic physiological motives; the top three levels of Maslow’s hierarchy of needs that we just mentioned are good examples. For the educational psychologist (see Chapter 13 for a more thorough coverage of the relation of educational psychology and learning), achievement motivation is an important topic. Achievement motivation is the need to be successful and engage in behaviors where personal effort and ability are instrumental in achieving success. It should not surprise you to learn that students who are high in achievement motivation are also successful in school (Stipek, 2002). Although it is not clear whether high achievement motivation occurs first and results in academic achievement, or vice versa, what is clear is that the patterns of success and achievement motivation do interact with one, in turn, perpetuating the other, and so forth. Hence, it is important to teachers that their students experience academic successes. As you will see in Chapter 13, all students do not learn in the same manner; some students are learning oriented, whereas other students are performance oriented (Koller & Baumert, 1997). In order to maximize learning success and achievement motivation, teachers must teach to their students’ strengths as much as possible.
Extinction
Extinction is a term that you will encounter throughout this book. Because extinction also results in a change in behavior, we thought it was an appropriate topic to include in this chapter. Extinction is a general term for the reduction or elimination of learned behavior. The specific procedure for producing extinction varies according to the specific type of learning that is involved. We will have more to say about the specifics of extinction in subsequent chapters.
A rather simplistic view of extinction is that it is the opposite of the process that produced the learned response. For example, if an association between a stimulus and a response occurred when learning took place, then extinction would simply involve the weakening or elimination of this association. As we will see, such simplistic views have run into difficulty in explaining several findings reported by learning psychologists. However, researchers and theorists have proposed numerous other theories to account for extinction. For example, Konorski (1948) proposed that extinction does not weaken an association, it results in the formation of a new association that serves to counteract the previously learned association. Whether the learned response is shown depends on the relative strength of these two associations. If the association that results in the display of the learned response is stronger and dominates, then that behavior will be shown. However, if the counteractive association that opposes the learned response is stronger and dominates, then the learned response is not shown and the researcher concludes that extinction has taken place.
We realize that extinction may seem to be a type of learning in which the human or animal is learning to not respond. Nonetheless, researchers and theorists typically treat extinction as a process that is separate from learning.
Check Your Learning
An emotional response is a composite of four main components: (a) physiological changes (b) the presence of an external or internal eliciting stimulus, (c) feelings of pleasantness or unpleasantness, and (d) the potential for a behavioral reaction. Because emotions play a role in adapting to the environment, researchers believe they are evolutionarily determined.
The opponent-process theory of emotion involves a definite sequence that has two components. First, there is the initial emotional reaction or a-process that is produced by the emotional stimulus. The a-process is followed by the b-process, which is the opposite of the a-process. The a-process is fast to develop and quick to dissipate; whereas, the b-process is slower to develop and longer lasting.
Motivation is an internal process that consists of three aspects: activation, direction, and maintenance of behavior.
Some motives, such as hunger and thirst, are physiologically determined; whereas, other motives, such as belongingness and love needs, esteem needs, and self-actualization are psychologically determined motives.
Cognitive dissonance is a psychological motivational state that occurs when a person has two incompatible thoughts. Cognitive dissonance, in turn, produces an internal state of tension or discomfort that the person seeks to reduce.
Achievement motivation is the need to be successful and engage in behaviors where personal effort and ability are instrumental in achieving success.
Extinction is a general term for the reduction or elimination of learned behavior.
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Learning in the Real World: Drug Addiction and the Opponent-Process Theory
The opponent-process theory of emotion provided researchers, theorists, counselors, and treatment specialists with a fresh new look at, and understanding of, drug addiction (Koob et al., 1997). We described the effects of amphetamines previously: an initial sense of euphoria and well-being that is followed by feelings of depression and tiredness after the drug has worn off. Let’s add to this description the fact that the initial euphoric effect or “rush” decreases and does not last as long the longer the person has been taking amphetamines (or any other addictive drug for that matter).
**** This decrease in the euphoric effect has a specific name among drug-treatment professionals. What do they call it? After reading this chapter, what is another appropriate name for this effect? Write down an answer for each of these questions before reading further.
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The decline in the effectiveness of a drug following repeated drug experiences is called tolerance. Drug tolerance is a very real example of habituation and can be considered the a-process according to the opponent-process theory. If you know someone who has smoked for several years and someone else who has just started smoking, you possibly can see an example of habituation first hand. The person who has recently started smoking is likely to enjoy smoking more than the long-term smoker. Why? The long-term smoker has habituated to the drug effects produced by smoking, whereas the novice smoker has yet to habituate. The same scenario certainly applies to the consumption of alcohol.
Now, if repeated exposures to a drug, such as amphetamines, result in habituation or drug tolerance (a-process), what is the b-process and how would the opponent-process predict it would occur? The b-process is the depression and tiredness that a person taking amphetamines experiences when the drug effects wear off. The opponent-process theory would predict that the person would experience only a small amount of depression and tiredness at first. However, as the number of drug episodes increases and habituation (drug tolerance) also increases because of the increase in the strength of the b-process, the person will begin to feel depressed and tired sooner and the reaction will last longer due to the slow decay of the strengthened b-process. (Now is a good time to review Part II of Figure 3-5.)
Certainly, depression and tiredness are states that most people would seek to avoid. What options does a drug user have to avoid these unpleasant states? Of course, the drug user could quit “cold turkey” and suffer the depression and tiredness until the b-process decays completely and these symptoms are gone. As we are sure you are well aware, this option is not especially popular. Addictive drug users find the “withdrawal effects” initiated by the b-process to be very noxious and will do nearly anything to avoid them. Hence, another option is to continue taking the drug because as long as the drug is taken, the desirable a-process will be present. Unfortunately, this option is easier said than done. Again, the b-process causes problems. To be sure, taking the drug continues to initiate the desired drug effects. However, we have seen that as the b-process grows stronger, the desired effects grow weaker and do not last as long. If your thinking jumped to more frequent administrations and larger does to help maintain, if not increase, the a-process, then you have a good grasp on how the drug user is thinking. You should also realize that there is nothing the drug user can do to combat the situation by continuing to take drugs either more frequently or in larger doses; either the drug user will suffer death due to an overdose or the b-process ultimately will overcome them and they will be at the mercy of the painful drug-withdrawal effects.
Without question, the drug-users addiction will (a) be very expensive, (b) likely result in trouble with the law, and (c) drastically reduce the user’s quality of life. Clearly, this is a no-win situation.
Margin Definitions
reflex
an innate response that is elicited by a specific stimulus
afferent (sensory) neuron
nerves that carry sensory signals to the central nervous system (spinal cord and brain)
interneuron
spinal cord neurons that connect afferent (sensory) neurons and efferent (motor) neurons
efferent (motor) neuron
nerves that carry motor signals from the central nervous system to the skeletal muscles and internal organs
tropism
behavior that is forced by a particular stimulus
fixed action pattern/modal action pattern
elicited, stereotyped response sequence that all members of a species display
ethology
the study of the behavior of animals in their natural environment
habituation
occurs when repeated presentations of a stimulus result in a decrease in the strength of the elicited response
sensitization
occurs when repeated presentation of a stimulus results in an increase in the strength of subsequent elicited responses
adaptation
a decrease in sensation that results from repeated presentation of a stimulus
external stimuli
stimuli that are received from the environment by our sense organs
internal stimuli
stimuli that are produced by the nervous system and internal organs
emotions
physiological changes and conscious feelings of pleasantness or unpleasantness, aroused by external or internal stimuli, that lead to behavioral reactions
opponent-process theory of emotional responding
assumes that an emotional response is composed of two separate, sequential reactions—the initial emotional reaction and the aftereffect of the opposite emotion
tolerance
decline in the effectiveness of a drug following repeated drug experiences
cognitive dissonance
a motivational state that occurs when a person has two incompatible thoughts
extinction
a general term for the reduction or elimination of learned behavior.
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