C H A P T E R
6 Behavior, Arousal,and Affective Valence The body of man is a machine which winds its own spring.
—J. O. De La Mettrie, 1748
Music hath charms to soothe a savage beast, To soften rocks, or bend a knotted oak.
—William Congreve, 1697
■ While taking an exam, a student is unable to retrieve an answer from memory. However, as soon as she exits the classroom, the answer comes to mind. Could the anxiety that was aroused by the exam have interfered with recall of the answer? This question and the following ones are provided as guides for understanding the concepts in this chapter:
1. In what ways is arousal similar and different from motivation?
2. What produces arousal?
3. Does arousal affect how well a person performs a task? If so, how?
4. Is arousal linked to the quality of our feelings? If so, what is the nature of this link?
5. How do incongruous events produce arousal? Do their resolutions contribute to the enjoyment of humor, music, and suspense?
Arousal and Performance Whether pushed by a motive or pulled by an incentive, physiological and psychological arousal accompanies behavior. In one case, arousal is in the background and affects the efficiency of ongoing behavior. In the other case, arousal is in the foreground felt as an affective experience. The following two quotes describing people’s experiences help clarify this distinction. The first quote illustrates the effects of arousal on performance.
My math anxiety started because of a teacher that I had for math in the third grade. We were learning our times tables, and she didn’t have any sympathy for the kids that were a little slower than the others. We would play a flash card game in front of the class, and if you got it wrong, she made you look like an idiot. So my anxiety comes from being afraid of being wrong in front of a group, and looking stupid. (Perry, 2004, p. 322)
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This next quote illustrates how arousal serves as an affective experience.
To her, the tension-and-release cycle that accompanies cinematic terror brings about some- thing like a gambler’s high. “It’s not that I’m a self-mutilator,” she [Ms. Gauh] said, “but it’s just a powerful rush when you can overcome some pain.” . . . “It’s the adrenaline,” said Sarah Stark, a movie theater manager in Lima, Ohio, explaining her long time interest in gory movies. For her, she said, violent horror movies amount to something of a personal endurance test, a bit like white-water rafting—the sheer terror of which clears the mind and, briefly, seems to reduce all of life down to a single exhilarating moment. (Williams, 2006, ¶ 12, 28)
The first quote by a student with math anxiety typifies the relationship between arousal and performance on a task. When arousal is high, as in the case of math anxiety, per- formance is low. If only math anxiety could be reduced, but not totally, then a student might perform better when solving math problems or taking a math test. The second quote is from individuals who enjoy watching horror movies. For them, movie scenes create a level of arousal that is optimal for creating a sense of pleasure, like a rush or moment of exhilaration.
The purpose of this chapter is to describe how these two functions of arousal help us to understand motivation. The intent of this first section is to describe arousal, its an- tecedents, and outcomes. It also covers how the quality of a person’s performance depends on the interaction between the level of arousal and the difficulty of the task being performed.
Categories of Arousal Arousal refers to the mobilization or activation of energy that occurs in preparation or dur- ing actual behavior. “My heart is pounding” implies physiological arousal while “I feel tense and anxious” implies psychological arousal. In combination with neurological or brain arousal, these are the different categories of arousal that have been studied.
Physiological Arousal. If you raced through your presentation during speech class with clammy hands, pounding heart, and dry throat, then you were physiologically aroused. Physiological arousal refers to those bodily changes that correspond to our feelings of being energized, such as sweaty palms and increased muscle tension, breathing, and heart rate. These changes indicate that the body is getting ready for action much like starting a car’s engine means that it’s ready to move. The autonomic nervous system controls physiological arousal and is divided into two branches: the sympathetic nervous system and the parasym- pathetic nervous system. The sympathetic nervous system is responsible for arousing or preparing the body for action. It stimulates the heart to pump blood more effectively. It causes glucose, epinephrine (adrenaline), and norepinephrine (noradrenaline) to be released in the bloodstream. The sympathetic nervous system also makes rapid breathing possible, which increases oxygen intake. The parasympathetic nervous system, however, is concerned with conserving the body’s energy. It is active during quiet periods and tends to counteract the arousing effects of the sympathetic system.
Brain Arousal. The activation of the brain, ranging from deep sleep to wakefulness to alertness, is referred to as brain arousal. Different areas of the brain are aroused depending on the operations being performed. Just as a car uses more fuel when it is moving, various areas of the brain also use more energy when active. This energy is in the form of glucose
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and oxygen. Two techniques for measuring brain activity make use of the fact that energy consumption increases in areas of the brain. Positron emission tomography (PET scan) is a procedure that produces a three-dimensional picture indicating areas of the brain that are most active. The picture is obtained by measuring positrons. These are particles with a positive charge that are emitted by radioactive substances injected into a person’s blood- stream and carried to the brain. These radioactive particles concentrate in those brain areas that have the highest blood flow or highest utilization of glucose. Another method for detecting brain activity makes use of functional magnetic resonance imaging (fMRI). This technique is used for obtaining high-resolution images of the brain from energy waves that are emitted from hydrogen atoms, which are released when the brain is surrounded by a strong magnetic field. The energy waves are influenced by the amount of oxygen in the blood of brain tissue. Just as our muscles need oxygen to work, increased blood flow and hence oxygen are provided to that part of the brain that is activated. Brain arousal is rele- vant for understanding subjective emotional experiences that map onto neural networks in the brain. This topic of affective feelings corresponding to brain activities is described in greater detail in Chapter 13.
Psychological Arousal. Is the anticipation felt prior to getting an exam back the same as the anticipation felt when opening a birthday present? Psychological arousal refers to how subjectively aroused an individual feels.An alternative strategy to relying on physiological in- dicators of arousal is to ask a person how subjectively aroused he feels. “I’m full of pep,” “I’m all psyched up,” or “I’m tired and have no energy” are verbal reports of various degrees of subjective arousal or activation. In researching subjective arousal, Thayer (1989) developed a theory of arousal that involves two dimensions: energetic arousal and tense arousal. Energetic arousal is a dimension characterized by a range of feelings from tiredness and sleepiness at the low end to alert and awake at the high end. High levels of energetic arousal are associated with a positive affective tone and optimism. For instance, energetic arousal could be associ- ated with planning a vacation trip. Tense arousal is a dimension characterized by a range of feelings from calmness and stillness at the low end to tension and anxiety at the high end. High levels of tense arousal are associated with a negative affective tone. The student’s description of math anxiety in the opening example is a case of tense arousal while the report from the horror-movie goers suggests their experience is a mixture of tense and energetic arousal.
The Scale Measuring Energetic Arousal and Tense Arousal in Table 6.1 provides a way of determining the intensity of each type of arousal that a person is momentarily ex- periencing. The items in Table 6.1 indicate that energetic arousal is associated with posi- tivity and pleasantness while tense arousal is associated with negativity and unpleasantness (Schimmack & Reisenzein, 2002). In validating these two types of arousal, Thayer (1978) found that students rated themselves more jittery and fearful (high tense arousal) on the day of an exam compared to a typical class day. Conversely, they were more likely to rate them- selves as being more placid and calm (low tense arousal) on a typical class day than on an exam day. Thayer also found that taking a brisk 10-minute walk elevated energetic arousal compared to sitting restfully for a similar amount of time. Resting, however, reduced an in- dividual’s level of tense arousal compared to walking.
➣ An older, more exhaustive measure of energetic and tense arousal is Thayer’s Activation- Deactivation Checklist, which is available at http://www.csulb.edu/~thayer/thayer/adacl.htm
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TABLE 6.1 Scale Measuring Energetic Arousal and Tense Arousal
The six dimensions below describe arousal, energy, or activation levels. Please circle the number of each dimension that indicates how you feel at this moment.
Energetic Arousal sleepy � 0 1 2 3 4 5 6 7 8 9 � awake
tired � 0 1 2 3 4 5 6 7 8 9 � alert
drowsy � 0 1 2 3 4 5 6 7 8 9 � wakeful
Tense Arousal at rest � 0 1 2 3 4 5 6 7 8 9 � restless
relaxed � 0 1 2 3 4 5 6 7 8 9 � tense
calm � 0 1 2 3 4 5 6 7 8 9 � jittery
Note: Sum all of your energetic arousal and tense arousal scores separately. The value of each score indicates the amount of each type of arousal that a person experiences at the moment.
Source: Based on “Experiencing Activation: Energetic Arousal and Tense Arousal Are Not Mixtures of Valence and Activation” by U. Schimmack and R. Reisenzein, 2002, Emotion, 2, p. 414.
Sources of Arousal Does loud music, the promise of a bonus, or playing a game energize you? These are ex- amples of stimuli, incentives, and behavior that all contribute to arousal and energization.
Stimuli. Someone calls out your name and you orient yourself toward the source of the sound. The sound of your name has both a cue function and an arousing function (Hebb, 1955). The cue function determines the type of response, and the arousing function deter- mines the intensity of the response. The arousal function of a stimulus is apparent from the energizing properties of music, which are described later in this chapter.
In addition to arousal from a specific stimulus, background stimuli also affect a person’s level of arousal. These stimuli, not the focus of an individual’s attention, consist of time of day, caffeine, and the process of being evaluated. Time-of-day effects are most obvious from people’s sleep-wake cycles: low arousal during sleep and high arousal when awake. Clements and associates (1976) had students in university classes that met at various times of the day fill out a scale that measured energetic arousal. The results showed that energetic arousal followed an inverted-U relationship with time of day.Arousal began low for 8 o’clock classes, rose to its highest levels for 12 and 2 o’clock classes, and then declined to its lowest value for evening classes. Other studies have also shown that psychological arousal in- creases from shortly after 8 A.M. to noon and 2 P.M. and then declines, reaching its lowest point prior to bedtime (Thayer, 1967, 1978). More subtle are changes in body temperature, which increases from 8 A.M. to 8 P.M. and then declines, as do changes in subjective alert- ness, which increases from 8 A.M. to around noon (Monk & Folkard, 1983). Caffeine from a cup of coffee boosts many people’s energetic arousal in the morning. As described in Chapter 4, the arousing effects of caffeine are considered pleasurable. Finally, we live in an age when many people suffer from evaluation anxiety, which occurs during exams, sports competition, and social situations (Zeidner & Matthews, 2005). Perhaps most pertinent to the reader is test anxiety and math anxiety, which are aroused in statistics courses.
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Collative Variables. In addition to stimulus intensity, other variables also affect arousal. Berlyne (1960) proposed the term collative variables to refer collectively to stimulus char- acteristics that include novelty, complexity, and incongruity. A novel stimulus is one that is new and different from the stimuli to which a person has become accustomed. For instance, given a choice between two stimuli that differ in novelty, grade school children are more likely to choose the more novel one. It is assumed that a more novel stimulus is also more arousing (Comerford & Witryol, 1993).
The complexity variable is determined by the number of elements and the dissimilar- ity of those elements in a stimulus array. The incongruity variable refers to the difference between a single element in the stimulus array that conflicts with or is discrepant from accompanying stimulus elements or from previous elements. Collative variables also affect an individual’s curiosity. Looking time increases as complexity of various stimuli increases, such as drawings, photographs, and works of art (Faw, 1970; Leckart & Bakan, 1965; Nicki & Moss, 1975).
Tasks. Arousal has also been linked to how much energy a person is willing to expend in order to successfully complete a task or attain an incentive (Brehm & Self, 1989; Duffy, 1962). The degree of arousal or energization for getting ready to act is based on three factors: (1) the severity of the person’s need, (2) the value of the incentive being pursued, and (3) the likelihood that successfully completing the behavior will actually result in the incentive (Brehm & Self, 1989). For example, a person may become little energized if the value of the incentive is low. A person may become greatly energized, however, if the incentive is high and if the chances of earning the incentive are moderate—that is, not too easy and not impossible. To illustrate, people who think they have a good chance at winning a coupon from a fast-food restaurant show an increase in heart rate and blood pressure in anticipation of the task required to earn the coupon (Wright & Dill, 1993). The increase in heart rate and blood pressure, which indicates energization, was greatest when participants were doing a difficult task but one they thought was achievable. Participants who thought they had little chance to succeed showed a smaller increase in heart rate and blood pressure on the difficult task. After all, why get energized over a task that cannot be accomplished?
Arousal and Behavior Psychologists are interested in how arousal affects the performance of a person working on various tasks. The next several pages examine the relationship between arousal and behav- ioral efficiency.
Arousal-Performance Relationships. Personal introspection leads to conflicting con- clusions about the relationship between arousal and performance efficiency. For example, a person might conclude that it is good to be somewhat aroused while giving a speech, although too much arousal results in poor delivery. However, even the mildest arousal might prevent a person from falling asleep while extreme arousal is necessary to run across the street to avoid being hit by a car. Perhaps the relationship between arousal and behavior depends on the nature of the task that is being performed. Let us examine two experiments on how arousal affects performance on different tasks: basketball free throws and reaction time. Is the efficiency of these two behaviors affected by arousal in the same way? For bas- ketball free-throw behavior, Wang and coresearchers (2004) had participants shoot 20 freeIS
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l F re
Low Anxiety High Anxiety
FIGURE 6.1 Anxiety and Free Throws. As anxiety increased, there was a decrease in the num- ber of successful basketball free throws out of 20 attempts.
Source: Adapted from “Coping Style and Susceptibility to Choking” by J. Wang, D. Marchant, & T. Morris, 2004, Journal of Sport Behavior, 27, table 1, p. 83.
throws in low- and high-pressure conditions designed to produce low and high arousal. First, participants shot free throws in the low-pressure condition, during which only one person was present who scored the shots and returned the ball. Next, in the high-pressure condition, participants shot their free throws while being videotaped in the presence of stu- dent spectators. In addition, participants received $1 for every shot they made plus an ad- ditional $4 was added or subtracted for every shot that exceeded or fell short of the number made in the low-pressure condition. In order to determine if all of these manipulations in- creased arousal, participants completed a scale that measured their cognitive anxiety and bodily anxiety. The high-pressure manipulations had the intended effect: cognitive and bod- ily anxiety were greater in the high-pressure than in the low-pressure condition. How was free-throw performance affected? Figure 6.1 shows that participants made significantly fewer free throws while more highly anxious. The main conclusion is that as arousal (anx- iety) increases, free-throw performance declines.
In the case of simple reaction time, Smith and coresearchers (2005) manipulated arousal with varying amounts of caffeine. On different days and in the space of 90 minutes, participants drank two beverages either both without caffeine, one with and one without caffeine, or both with caffeine. The simple reaction time task consisted of participants pressing a key as soon as they saw a square appear on the computer screen. Did caffeine- induced arousal affect reaction time? Figure 6.2 shows that a greater amount of caffeine produced faster reaction times. The main conclusion is that as caffeine-induced arousal in- creases, reaction time becomes faster.
Yerkes-Dodson Law. Notice that these two experiments provide different conclusions re- garding the effects of arousal on performance. In one case (Figure 6.1) increases in arousal reduces performance while in the other case (Figure 6.2) it improves performance. Two hy- potheses suggest themselves for these results. First, some arousal helps performance but too much arousal hinders it. Second, the amount of arousal depends on the nature of the task, such as free throws versus reaction time. The first hypothesis describes an inverted-U
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ca l o
No Coffee One Coffee
20 Two Coffees
FIGURE 6.2 Caffeine and Reaction Time. Reaction speed became faster with an increase in the amount of caffeinated coffee that participants drank. Reciprocals of reaction times (� 1000) were computed in order to associate taller bars with faster reaction times. The RTs were 366, 353, and 343 milliseconds for no, one, or two coffees, respectively.
Source: Adapted from “Effects of Repeated Doses of Caffeine on Mood and Performance and Fatigued Volunteers” by S. A. Smith, D. Sutherland, & G. Christopher, 2005, Journal of Psychopharmacology, 19, table 1, p. 624.
arousal-performance relationship: as arousal increases, performance increases, levels off, and then decreases (Hebb, 1955; Malmo, 1959). The two inverted-U curves in Figure 6.3 show that for each task an intermediate level of arousal is considered optimal—that is, the level that is associated with the best performance.
The second hypothesis suggests that the optimal level of arousal changes with the nature of the task being performed. In other words, the optimal level of arousal is not fixed but depends on the complexity or difficulty of the task being performed. This complication
Level of Stimulation or Arousal
Harder task Easier task
FIGURE 6.3 Yerkes-Dodson Law. Each curve shows the inverted-U arousal-performance rela- tionship. As arousal increases, performance increases and levels off; further increases in arousal lead to decreases in performance. According to the Yerkes-Dodson law, the optimal level of arousal is lower for harder tasks than for easier tasks. The optimal level of arousal is associated with the best performance at a task.
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was an early discovery in the history of psychology by Yerkes and Dodson (1908). They trained mice to discriminate between a white box and a black box at three levels of difficulty. In the process of learning, if the mouse made the wrong choice, it received an electric shock, which varied in intensity from weak to medium or strong. The strong electric shock “was decidedly disagreeable to the experimenters and the mice reacted to it vigorously” (pp. 467–468). The intensity of the shock has come to be equated with the level of arousal, although Yerkes and Dodson did not interpret their experiment in terms of arousal but in terms of the intensity of (electrical) stimulation. The results of their experiment show that performance on the discrimination problem depended on problem difficulty and on shock intensity. For easy discrimination problems, performance increased across all levels of shock intensity and almost never declined. For difficult discrimination problems, however, perfor- mance increased with shock intensity and then decreased. Medium-difficult discriminations showed the most pronounced inverted-U relationship. These findings became known as the Yerkes-Dodson law: low arousal produces maximal performance on difficult tasks, and high arousal produces maximal performance on easy tasks. This law is diagrammed in Figure 6.3.
Zones of Optimal Functioning. Experiments showing inverted-U relationships be- tween arousal and task performance have been scarce, however (Neiss, 1988). A reason for the shortage of evidence is that individuals have different optimal levels of arousal. The same general curve does not apply to everyone. The zone of optimal functioning hypothesis in sports psychology postulates individual inverted-U curves each with a zone of optimal arousal where an athlete performs best (Hanin, 1989). Arousal below or above this zone leads to poorer performance. The zone applies to different psychological vari- ables and has been tested most frequently with cognitive anxiety and somatic anxiety. Cognitive anxiety refers to negative expectations and mental concerns about performance in a competitive situation. Somatic anxiety refers to the self-perception of physiological arousal associated with nervousness and tension. In a test of the zone of optimal function hypothesis, Krane (1993) examined the relationship between cognitive anxiety and somatic anxiety and the performance of women players during soccer matches. Each player filled out the two anxiety scales about 20 minutes prior to each of the season’s 12 soccer matches. A player’s optimal zone for cognitive anxiety was defined as between one stan- dard deviation below and above her season’s cognitive anxiety mean. Her somatic anxiety zone was also defined as between one standard deviation below and above her season’s so- matic anxiety mean. At the end of the season, each player’s soccer match performance was classified as below, within, or above her optimal zone for cognitive and for somatic anxi- ety. Krane found partial support for the hypothesis. A player performed best when she was within but also below her optimal zone and played worst when above her zone.
The zone of optimal functioning for cognitive anxiety and somatic anxiety has also been examined with swimmers. Davis and Cox (2002) measured cognitive anxiety and somatic anxiety 10 minutes prior to a highschool swimmer’s preferred event. Each swimmer’s mean and standard deviation for cognitive anxiety and for somatic anxiety was computed for the season. In this study, a swimmer’s optimal zone was defined as between one-half standard deviation below and above the mean for the season. The results for cognitive anxiety, but not for somatic anxiety, supported the zone of optimal functioning hypothesis. Swimmers swam faster when in their optimal zone for cognitive anxiety and slower when below or above their zone. Swimming times did not differ for the three somatic anxiety zones.
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Section Recap Arousal refers to energy mobilization and activation of a person prior to or while engaged in behavior. Arousal occurs in several modes. Physiological arousal refers to excitement of the body, as reflected by sweaty palms and increased muscle tension, breathing, and heart rate. The sympathetic nervous system is responsible for stimulating the heart to pump blood more effectively, the liver to release glucose, the release of epinephrine (adrenaline) and norepinephrine (noradrenaline), and increased oxygen uptake. Brain arousal refers to activation of various areas of the brain as a person performs various activities. Brain arousal is measured by positron emission tomography (PET scan), which is a procedure that pro- duces a three-dimensional brain picture indicating areas that are most active. Brain arousal is also measured with a functional magnetic resonance imaging (fMRI) procedure that pro- vides an image showing the degree of activity in a particular brain area. A third mode of arousal is psychological arousal, which refers to how subjectively aroused an individual feels. Psychological arousal is composed of energetic and tense dimensions. Energetic arousal is associated with positive affect, while tense arousal is associated with anxiety and fearfulness.
Arousal itself stems from several sources. A stimulus, for example, has an arousing function and a cue function. In addition, background stimuli which do not capture a per- son’s attention also increase arousal. Arousal varies with time of day, being highest around noon and lower in the morning and evening. Coffee boosts arousal as does the process of being evaluated during exams or sports competition. Arousal also depends on collative vari- ables, including characteristics like novelty, complexity, and incongruity. A task also can be a source of arousal, since it energizes or activates a person even before he begins working on it. Task-induced arousal is based on a person’s need, value of the task’s outcome, and chances of success. Sometimes arousal increases behavioral efficiency and in other in- stances decreases it. This inconsistency is handled by an inverted-U relationship and the Yerkes-Dodson law.
According to the inverted-U relationship, as arousal increases, performance on a task increases and then decreases. According to the Yerkes-Dodson law, the high point of the inverted-U or arousal-performance relationship depends on the complexity of the task being performed. Low arousal produces maximal performance on difficult tasks, and high arousal produces maximal performance on easy tasks. According to the zone of optimal functioning hypothesis, each individual has her preferred zone of arousal based on cogni- tive or somatic anxiety. Athletic performance is better within the zone and worse below and above it.
Theories about the Performance-Arousal Relationship Several theories have been proposed to explain the inverted-U arousal-performance rela- tionship. The classic Hull-Spence drive theory emphasizes how arousal affects performance with little regard for any cognitive awareness on the part of the individual. The cusp catas- trophe model in sports psychology, the cue utilization hypothesis, and the processing effi- ciency theory are more concerned with the cognitive aspects of arousal and how this affects behavioral efficiency. The purpose of this section is to describe each theory along with some exemplary evidence for its support.
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Hull-Spence Drive Theory What determines whether arousal aids or hinders performance? The answer depends on whether arousal is energizing a correct response or an incorrect response. For instance, correct responses occur more readily with easy tasks, while incorrect responses are initially more likely with difficult tasks. Spence and his associates (1956a, 1956b) employed Hull’s (1943, 1952) drive concept to account for the finding that high drive or arousal aids in the performance of easy tasks but hinders the performance of difficult tasks. For Hull, drive was a persistent inter- nal stimulus or pushing action of a physiological need. The stronger the drive, the greater the pushing action on all responses. Thus, for a simple task as drive increases, the strength of the correct response increases, as does the difference between the correct and the wrong responses. In a complex task, however, the most dominant response is often not the correct one. As drive increases, the strength of wrong responses increases, as does the difference between these responses and the correct one. For the correct response to occur in these situations, the incor- rect response must be weakened and the correct one strengthened.
To test this hypothesis, Spence and associates compared the learning of simple versus difficult paired associate tasks (Spence et al., 1956a, 1956b). In paired associate learning, a participant must learn to associate two words together such that a stimulus word cues the participant to say the associated response word. The simple paired associate task involved such pairs of words as complete-thorough and empty-vacant. It is easy to learn the response thorough to the stimulus complete, since these words have similar meanings. With these pairs, an increase in drive should make the occurrence of the dominant but correct response more likely, and hence learning should be faster. The difficult task involved pairs such as quiet-double and serene-headstrong. These pairs are more difficult to learn because the re- sponses double and headstrong are going to compete when the stimuli quiet or serene are presented. The reason is because quiet and serene are similar in meaning and thus will evoke the same response. An increase in drive in this case should also increase the likelihood of the dominant response, which is now the wrong response. This development should make learning more difficult. Drive or arousal in this experiment was defined by the participant’s level of trait anxiety as measured by an anxiety scale. Participants low in trait anxiety were defined as low drive, and those high in trait anxiety were defined as high drive. The results confirmed the prediction: high-drive participants learned the easy paired associate task faster than did low-drive participants. High-drive participants, however, learned the difficult paired associate task slower than did low-drive participants (Spence et al., 1956a, 1956b).
Cusp Catastrophe Model Sports is one of those endeavors in which it is very important to control arousal in order to maximize performance. Arousal factors that determine athletic performance are addressed in the cusp catastrophe model from sports psychology, which holds that there are two types of arousal: cognitive anxiety and physiological arousal (somatic anxiety) (Hardy, 1996a, 1996b). At low physiological arousal, increases in cognitive anxiety produce a slight improvement in athletic performance while at high physiological arousal, increases in cognitive anxiety pro- duce a decline in performance. Also, at lower levels of cognitive anxiety, increases in physio- logical arousal lead to small gradual increases and then decreases in athletic performance resembling a flattened inverted-U curve. However, at midrange or higher levels of cognitive anxiety, increases in physiological arousal lead to a cusp where performance is best. Here an
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athlete is described as a “clutch” player. Increases in physiological arousal beyond this cusp, however, result in a sudden and dramatic drop in performance. At this point the athlete “chokes” and performs very badly.
One implication of the cusp catastrophe model is that the drop in performance can be so drastic that it is manifested as freezing—that is, the individual ceases all behavior. Freez- ing, also known as tonic immobility, refers to a lack of behavior that occurs in reaction to extremely stressful circumstances. Tonic immobility is characterized by the absence of movement, lack of responsiveness, the tendency to maintain the same posture, remaining silent, an unresponsiveness to pain, and yet a tendency to remain alert (Moskowitz, 2004). Freezing occurs in many animals but also in humans during stressful situations. It has been induced in a variety of birds, chickens, and rats by holding them on their backs for 15 to 30 seconds (Gallup et al., 1970; Ratner, 1967). Freezing occurs in animals when they are attacked by predators, at which time tonic immobility serves as an adaptive strategy. If the prey animal has unsuccessfully tried to escape or fight back, then it freezes as if it were feigning death (Ratner, 1967). Marks (1987) comments on the evolutionary significance of freezing by noting that many predators only attack and kill moving prey. When prey freezes, predators lose interest and their attention lapses, which provides an opportunity for prey to escape. Hawks, for example, do not eat dead animals and would starve if not provided with moving prey to eat (Marks, 1987).
However, when freezing occurs in humans it is usually in situations where it is not adaptive, especially in emergency situations. Leach (2004) provides some descriptions of people’s behavior during emergency situations. For example, the passenger ferry MV Estonia sank in September 1994 in the Baltic Sea. While sinking, passengers were seen standing still as if paralyzed, exhausted, or in shock. Or they were just sitting incapable of doing anything. In another case, a North Sea oil platform exploded as a result of natural gas accumulation in July 1988. Leach reports that many workers made no attempt to leave the platform and one worker just slumped down unable to move. Another emergency example is the case of an airplane that returned to a Manchester, England, airport in 1985. Upon land- ing it was discovered that one of the engines was on fire. Unfortunately, there were delays in evacuating the plane because many passengers froze; in fact, “. . . several people were seen to remain in their seats until they became engulfed in flames” (Leach, 2004, p. 540).
According to evolutionary psychology (Chapter 3), human nature evolved because it had survival value. Is freezing a case of evolutionary old behavior intruding into frighten- ing emergency situations in the present? Yes, according to Moskowitz (2004), who wrote that tonic immobility in humans is a holdover from our evolutionary past during which time humans were also prey. Just like animals today freeze in order to increase their chances for survival, so did humans long ago. Thus, freezing that occurs in emergency situations like sinking ships or burning airplanes are really remnants of this behavior that once provided a survival advantage. Unfortunately, in such situations, freezing is incompatible with the behavior that is required for escape.
Cue Utilization Hypothesis A cognitive explanation of the inverted-U arousal–performance relationship is provided by Easterbrook’s (1959) cue utilization hypothesis, which holds that the number of cues or amount of information utilized by a person in any situation tends to decline with an increase
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in arousal. Usually, the use of peripheral and irrelevant cues is reduced, while the use of central and relevant cues is maintained. In the case of simple tasks, irrelevant cues are more likely to be excluded with increasing arousal; thus, more attention can be given to task- relevant cues. Complex tasks, however, involve many cues. Arousal involves the exclusion of task-relevant cues as well, and consequently performance declines. One reason for the reduction in utilizing task-relevant cues comes from the attention-grabbing nature of auto- nomic nervous system arousal (Mandler, 1975, 1984). A pounding heart and butterflies in the stomach compete for attention, allowing less attention to be devoted to the task at hand; as a consequence, performance declines.
Research on memory and emotionally arousing events has supported Easterbrook’s cue utilization hypothesis. For example, arousal should enhance the memory for major or central details of an event but not for peripheral or irrelevant details. In two questionnaire studies, Christianson and Loftus (1990) asked university students to recall the most traumatic events in their lives. Students were asked how many central and peripheral details they remembered. Central details are relevant and directly associated with the traumatic event, while peripheral details are neither relevant nor directly associated. Students were also asked how strong their emotional feelings were during the event and how strong their emotional feelings were in recalling the event. The results showed that participants remembered more central details than peripheral details. Furthermore, the more intense their emotional feelings about the event, the more likely they were to remember central but not peripheral details.
Are there some events, such as the events of September 11, 2001, so ingrained in our memories that we will never forget them, even if we want to? Is the memory for extremely emotional and arousing events somehow different than the memory for the more mundane things of life? One answer to these questions is based on a theory about the relationship between arousal and a shift in memory systems. This theory, by Metcalfe and Jacobs (1998), postulates the existence of two memory systems, with the level of arousal determining which system is operating. Such a theory postulates the existence of a cool memory system and a hot memory system, each in a different area of the brain. The cool system, which is localized in the hippocampus, serves the memory of events occurring in space and time. For example, this system would help a person to remember the location of her residence and that her car is parked in a different spot today than yesterday. The hot system, which is localized in the amygdala, serves as the memory of events that occur under high arousal. The hot system is responsible for the intrusive memories of individuals who have experienced extremely traumatic events years earlier.
The level of activation of the cool and hot memory systems depends on the level of arousal (Metcalfe & Jacobs, 1998). The degree of activation or efficiency of the cool system follows the inverted-U curve shown in Figure 6.3. As arousal increases, activation of this memory system increases, levels off, and then decreases. The system is most efficient at intermediate levels of arousal but inefficient at very high levels. The hot memory system, however, shows increasing levels of activation with increasing amounts of arousal. This sys- tem is least efficient at low levels of arousal but most efficient at very high levels of arousal. Both systems interact to determine a person’s total memory. However, the cool system is most functional at low and intermediate levels of arousal, while the hot system is most func- tional at high levels. Thus, where the cool system leaves off, the hot system takes over. Metcalfe and Jacobs further theorize that the hot system is geared up for remembering the
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details of stimuli that predict the onset of highly stressful or arousing events, such as events that predict danger.
Processing Efficiency Theory Evaluations occur in many facets of life, such as exams, sports competition, and social set- tings, and can become sources of anxiety in those situations (Zeidner & Matthews, 2005). However, the level of anxiety individuals experience in evaluative situations depends on their disposition to become anxious—that is, some people become anxious quicker than others. So, imagine being evaluated for speed and accuracy for attempting to solve “in your head” problems like: 478 � 59 � ? Does your level of math anxiety, in this case, affect your problem solving efficiency?
Trait vs. State Anxiety. Anxiety is not a single entity but instead consists of two parts: trait and state. Trait anxiety is an individual difference measure of the disposition to per- ceive environmental events as threatening and to respond anxiously. State anxiety refers to the actual feelings of apprehension, worry, and sympathetic nervous system arousal that are evoked by threatening situations (Spielberger, 1975). In other words, trait anxiety is the propensity to react with state anxiety in threatening situations, such as evaluation that occurs during exams, sports competition, and social settings. For example, trait anxiety is the disposition to become anxious (state anxiety) during a math test. In general, state anx- iety is damaging to performance especially on tasks that are complex (Zeidner & Matthews, 2005). But, how does anxiety affect performance?
Anxiety and Processing Efficiency. According to processing efficiency theory, anxiety expresses itself as worry, which is a preoccupation with evaluation and concerns about per- formance. Worry, in turn, takes up working-memory capacity and with less working-memory available performance on cognitive tasks declines (Eysenck & Calvo, 1992). Anxiety and accompanying worry are especially telling in their effects on math problems. For instance, solving the problem 478 � 59 requires a person to retain intermediate solutions (7 and “carry 1”) in her working memory. According to processing efficiency theory, the capacity of working memory to retain an intermediate solution decreases because of the presence of in- trusive thoughts of worry. Experimental evidence is provided by Ashcraft and Kirk (2001), who compared low, medium, and high math anxiety students for accuracy in working math problems. Some problems did not require “carrying operations” (15 � 2) and other problems did (23 � 18). The effects of anxiety was only apparent with problems that required carrying operations. As math anxiety increases and uses more working memory space, problem solv- ing efficiency decreases for problems that require carrying operations.
Math anxiety appears to be unique.Ashcraft and Kirk (2001, exp. 3) hypothesized that math anxiety only affected the working-memory capacity for numbers but not for letters. In their experiment, they compared the effects of anxiety on working-memory capacity for numbers versus working-memory capacity for letters. A participant’s level of math anxiety was measured with a scale similar to the Abbreviated Math Anxiety Scale. With this scale, participants answer questions about how much anxiety is evoked in situations relevant to mathematics (Hopko et al., 2003). Examples may include using a table in a math book, lis- tening to a lecture in math class, or being given a “pop” quiz in math class. During the actual
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Math Anxiety High
FIGURE 6.4 Math Anxiety and Performance. As math anxiety increased, working-memory ca- pacity for arithmetic decreased. Specifically, as math anxiety increased computation span with numbers decreased while listening span for letters did not decrease significantly.
Source: Adapted from “The Relationship among Working Memory, Math Anxiety, and Performance” by M. H. Ashcraft and E. P. Kirk, 2001, Journal of Experimental Psychology: General, 130, table 3, p. 233.
experiment, the researchers used a listening-span task to measure the working-memory capacity for letters and used a computation-span task to measure the working-memory capacity for numbers. For the listening span, participants heard a number of simple sentences, answered a question about each, and were required to remember the last word of each sen- tence. For example, “It rained yesterday.” When? “The dog sat on the porch.” Where? After hearing and answering a number of such sentences, participants were asked to recall the last word in each sentence in the correct order (e.g., yesterday, porch). The mean number of words recalled correctly defined the letter-span size. The computation-span task resembled the listening-span task. The participant heard a series of simple problems, such as 7 � 3 � ? followed by 2 � 6 � ? They were required to solve each problem and also to remember the last number of each. At the recall, participants had to name the last number of each prob- lem in the correct order (e.g., 3, 6). The amount recalled correctly defined the working- memory capacity for numbers. Ashcraft and Kirk reasoned that on the basis of processing efficiency theory, math anxiety should negatively influence working-memory capacity for numbers but not for letters. Their results in Figure 6.4 show that as anxiety increased, working- memory capacity for numbers (computation span) decreased while the capacity for letters (listening span) was affected slightly, although not significantly. If working memory is not used to capacity, then anxiety has little effect on math performance. However, when used to capacity as in this experiment, anxiety has a detrimental effect on math performance.
Section Recap There are several theories that help explain the inverted-U arousal-performance relation- ship. According to the Hull-Spence theory, arousal magnifies the intensity of all responses. In a simple task, arousal magnifies the dominant response, which is usually the correct one. Arousal of the dominant response in complex tasks is most likely to be the incorrect
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response. According to the cusp catastrophe model, performance efficiency is based on the interaction between physiological (somatic) anxiety and cognitive anxiety. At low cognitive arousal, performance increases moderately as physiological arousal increases and then decreases. At high cognitive arousal, however, performance increases and then catastroph- ically drops as physiological arousal increases. During extremely arousing and dangerous situations a person may exhibit tonic immobility, which refers to freezing. This behavior was adaptive in our evolutionary past to escape predators but today that behavior interferes with escape from danger, such as in the case of sinking ships or burning airplanes. According to the cue utilization hypothesis, the amount of information utilized in a situa- tion declines as arousal increases. In simple tasks there is a decline in the use of irrele- vant cues, and in complex tasks there can also be a decline in task-relevant cues as arousal increases. According to memory research, as arousal increases there is better recall of central detail and a decrease in the recall of peripheral detail. One theory is that a cool memory system works best under moderate arousal, while a hot memory system works best under high arousal. Thus, as arousal increases there is a shift from a cool to a hot memory system.
Many individuals suffer from evaluation anxiety, which occurs during exams, sports competition, and social situations. Trait anxiety is an individual difference variable to respond negatively and with worry to the environment in general, while state anxiety refers to feelings of apprehension activated by a particular situation. According to processing efficiency theory, state anxiety—especially in math—expresses itself as worry, which takes up working-memory capacity. As a result of increasing state anxiety, solving math problems declines in efficiency, especially when carrying operations are involved.
Arousal and Affective Valence When considered an independent variable, arousal affects performance: some arousal aids performance but too little or too much hinders it. When considered a dependent variable, arousal depends on the collative variables of novelty, complexity, and incongruity. Humans are both pushed and pulled toward experiencing arousal at a certain intensity and valence. Arousal experiences are provided by collative variables like novelty in new fashions; complexity in art, music, or movies; and incongruity in jokes. This section examines the motivation that humans have for two components of arousal: intensity and valence.
Variation in Affective Valence Can a person be aroused or energized but still feel subjectively neutral? Or is arousal always accompanied by a positive or negative feeling (Thayer, 1989)? Riding a roller coaster, watching a suspenseful movie, or attending a good party are arousing and provide positive affective experiences. A near traffic accident, witnessing a violent crime, or being insulted are arousing and produce negative affective experiences. While being performed, strenuous exercise may feel negative and arousing, but when completed it feels pleasant while some arousal still remains. Thus, arousal is not neutral but instead has a positive or negative feel to it (Thayer, 1989; Watson & Tellegen, 1985). In trying to determine how the level of arousal regulates behavior, it may be difficult to separate affective valence from arousal (Neiss, 1988). Consequently, both arousal and associated affective valence must be kept in mind when describing behavior.