18.3: Organizational Influences on Stress
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We will now consider several factors that have been found to influence both frustration and anxiety; we will present a general model of stress, including its major causes and its outcomes. Following this, we will explore several mechanisms by which employees and their managers cope with or reduce experienced stress in organizations. The model presented here draws heavily on the work of several social psychologists at the Institute for Social Research of the University of Michigan, including John French, Robert Caplan, Robert Kahn, and Daniel Katz. In essence, the proposed model identifies two major sources of stress: organizational sources and individual sources. In addition, the moderating effects of social support and hardiness are considered. These influences are shown in \(\PageIndex{1}\).
We begin with organizational influences on stress. Although many factors in the work environment have been found to influence the extent to which people experience stress on the job, four factors have been shown to be particularly strong. These are (1) occupational differences, (2) role ambiguity, (3) role conflict, and (4) role overload and underutilization. We will consider each of these factors in turn.
Occupational Differences
Tension and job stress are prevalent in our contemporary society and can be found in a wide variety of jobs. Consider, for example, the following quotes from interviews with working people. The first is from a bus driver:
“You have your tension. Sometimes you come close to having an accident, that upsets you. You just escape maybe by a hair or so. Sometimes maybe you get a disgruntled passenger on there who starts a big argument. Traffic.  There’s a lot of tension behind that. . . . Most of the time you have to drive for the other drivers, to avoid hitting them. So, you take the tension home with you. Most of the drivers, they’ll suffer from hemorrhoids, kidney trouble, and such as that. I had a case of ulcers behind it.”
Or consider the plight of a bank teller:
“Some days, when you’re aggravated about something, you carry it after you leave the job. Certain people are bad days. (Laughs.) The type of person who will walk in and say, ‘My car’s double-parked outside.   But you can’t. That’s the one hassle. You can’t say anything back. The customer’s always right.”
Stress is experienced by workers in many jobs: administrative assistants, assembly-line workers, foremen, waitresses, and managers. In fact, it is difficult to find jobs that are without some degree of stress. We seldom talk about jobs without stress; instead, we talk about the degree or magnitude of the stress.
The work roles that people fill have a substantial influence on the degree to which they experience stress. These differences do not follow the traditional blue-collar/white-collar dichotomy, however. In general, available evidence suggests that high-stress occupations are those in which incumbents have little control over their jobs, work under relentless time pressures or threatening physical conditions, or have major responsibilities for either human or financial resources.
A recent study attempted to identify those occupations that were most (and least) stressful. The study results are presented in Table \(\PageIndex{1}\). As shown, high-stress occupations (firefighter, race car driver, and astronaut) are typified by the stress-producing characteristics noted above, whereas low-stress occupations (musical instrument repair person, medical records technician, and librarian) are not. It can therefore be concluded that a major source of general stress emerges from the occupation at which one is working.
| The Most and Least Stressful Jobs | |
|---|---|
| High-Stress Jobs | Low-Stress Jobs |
| Source: Adapted from The Jobs Rated Almanac by Les Krantz. 1988 Les Krantz. | |
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A second survey, by the American Psychological Association, examined the specific causes of stress. The results of the study showed that the most frequently cited reasons for stress among administrative professionals are unspecified job requirements (38 percent), work interfering with personal time (36 percent), job insecurity (33 percent), and lack of participation in decision-making (33 percent).
Finally, a study among managers found that they, too, are subject to considerable stress arising out of the nature of managerial work. The more common work stressors for managers are shown in Table \(\PageIndex{2}\).
| Typical Stressors Faced by Managers | |
|---|---|
| Stressor | Example |
| Source : Adapted from D. Zauderer and J. Fox, “Resiliency in the Face of Stress,” Management Solutions , November 1987, pp. 32–33. | |
| Role ambiguity | Unclear job duties |
| Role conflict | Manager is both a boss and a subordinate. |
| Role overload | Too much work, too little time |
| Unrealistic expectations | Managers are often asked to do the impossible. |
| Difficult decisions | Managers have to make decisions that adversely affect subordinates. |
| Managerial failure | Manager fails to achieve expected results. |
| Subordinate failure | Subordinates let the boss down. |
These stressors range from task ambiguity and role conflict to overwork and the possibility of failure. Indeed, responsibility for others may be the greatest stressor of all for managers. Studies in the United States and abroad indicate that managers and supervisors consistently have more ulcers and experience more hypertension than the people they supervise. Responsibility for people was found to be a greater influence on stress than responsibility for non-personal factors such as budgets, projects, equipment, and other property. As noted by French and Caplan:
“If there is any truth to the adage that ‘man’s greatest enemy is himself,’ it can be found in these data—it is the responsibility which organizational members have for other organizational members, rather than the responsibility for impersonal aspects of the organization, which constitutes the more significant organizational stress.”
Thus, a person’s occupation or profession represents a major cause of stress-related problems at work. In addition to occupation, however, and indeed closely related to it, is the problem of one’s role expectations in the organization. Three interrelated role processes will be examined as they relate to experienced stress: role ambiguity, role conflict, and role overload or underutilization.
Role Ambiguity
The first role process variable to be discussed here is role ambiguity . When individuals have inadequate information concerning their roles, they experience role ambiguity. Uncertainty over job definition takes many forms, including not knowing expectations for performance, not knowing how to meet those expectations, and not knowing the consequences of job behavior. Role ambiguity is particularly strong among managerial jobs, where role definitions and task specification lack clarity (refer to Table \(\PageIndex{2}\)). For example, the manager of accounts payable may not be sure of the quantity and quality standards for her department. The uncertainty of the absolute level of these two performance standards or their relative importance to each other makes predicting outcomes such as performance evaluation, salary increases, or promotion opportunities equally difficult. All of this contributes to increased stress for the manager. Role ambiguity can also occur among non-managerial employees—for example, those whose supervisors fail to make sufficient time to clarify role expectations, thus leaving them unsure of how best to contribute to departmental and organizational goals.
How prevalent is role ambiguity at work? In two independent surveys of employees, it was found that 35 percent of one sample (a national random sample of male employees) and 60 percent of the other sample (primarily scientists and engineers) reported some form of role ambiguity. Hence, ambiguity of job role is not an isolated event.
Role ambiguity has been found to lead to several negative stress-related outcomes. French and Caplan summarized their study findings as follows:
“In summary, role ambiguity, which appears to be widespread, (1) produces psychological strain and dissatisfaction; (2) leads to underutilization of human resources; and (3) leads to feelings of futility on how to cope with the organizational environment.”
In other words, role ambiguity has far-reaching consequences beyond experienced stress, including employee turnover and absenteeism, poor coordination and utilization of human resources, and increased operating costs because of inefficiency.
It should be noted, however, that not everyone responds in the same way to role ambiguity. Studies have shown that some people have a higher tolerance for ambiguity and are less affected by role ambiguity (in terms of stress, reduced performance, or propensity to leave) than those with a low tolerance for ambiguity. Thus, again we can see the role of individual differences in moderating the effects of environmental stimuli on individual behavior and performance.
Role Conflict
The second role-related factor in stress is role conflict . This may be defined as the simultaneous occurrence of two (or more) sets of pressures or expectations; compliance with one would make it difficult to comply with the other. In other words, role conflict occurs when an employee is placed in a situation where contradictory demands are placed upon her. For instance, a factory worker may find himself in a situation where the supervisor is demanding greater output, yet the work group is demanding a restriction of output. Similarly, a secretary who reports to several supervisors may face a conflict over whose work to do first.
One of the best-known studies of role conflict and stress was carried out by Robert Kahn and his colleagues at the University of Michigan. Kahn studied 53 managers and their subordinates (a total of 381 people), examining the nature of each person’s role and how it affected subsequent behavior. As a result of the investigation, the following conclusions emerged:
Contradictory role expectations give rise to opposing role pressures (role conflict), which generally have the following effects on the emotional experience of the focal person: intensified internal conflicts, increased tension associated with various aspects of the job, reduced satisfaction with the job and its various components, and decreased confidence in superiors and in the organization as a whole. The strain experienced by those in conflict situations leads to various coping responses, social and psychological withdrawal (reduction in communication and attributed influence) among them.
Finally, the presence of conflict in one’s role tends to undermine her reactions with her role senders and to produce weaker bonds of trust, respect, and attraction. It is quite clear that role conflicts are costly for the person in emotional and interpersonal terms. They may be costly to the organization, which depends on effective coordination and collaboration within and among its parts.
Other studies have found similar results concerning the serious side effects of role conflict both for individuals and organizations. It should again be recognized, however, that personality differences may serve to moderate the impact of role conflict on stress. In particular, it has been found that introverts and people who lack flexibility respond more negatively to role conflict than do others. In any event, managers must be aware of the problem of role conflict and look for ways to avert negative consequences. One way this can be accomplished is by ensuring that their subordinates are not placed in contradictory positions within the organization; that is, subordinates should have a clear idea of what the manager’s job expectations are and should not be placed in “win-lose” situations.
Role Overload and Underutilization
Finally, in addition to role ambiguity and conflict, a third aspect of role processes has also been found to represent an important influence on experienced stress—namely, the extent to which employees feel either overloaded or underutilized in their job responsibilities. Role overload is a condition in which individuals feel they are being asked to do more than time or ability permits. Individuals often experience role overload as a conflict between quantity and quality of performance. Quantitative overload consists of having more work than can be done in a given time period, such as a clerk expected to process 1,000 applications per day when only 850 are possible. Overload can be visualized as a continuum ranging from too little to do to too much to do. Qualitative role overload, on the other hand, consists of being taxed beyond one’s skills, abilities, and knowledge. It can be seen as a continuum ranging from too-easy work to too-difficult work. For example, a manager who is expected to increase sales but has little idea of why sales are down or what to do to get sales up can experience qualitative role overload. It is important to note that either extreme represents a bad fit between the abilities of the employee and the demands of the work environment. A good fit occurs at that point on both scales of workload where the abilities of the individual are relatively consistent with the demands of the job.
There is evidence that both quantitative and qualitative role overload are prevalent in our society. A review of findings suggests that between 44 and 73 percent of white-collar workers experience a form of role overload. What induces this overload? As a result of a series of studies, French and Caplan concluded that a major factor influencing overload is the high achievement needs of many managers. Need for achievement correlated very highly both with the number of hours worked per week and with a questionnaire measure of role overload. In other words, much role overload is apparently self-induced.
Similarly, the concept of role underutilization should also be acknowledged as a source of experienced stress. Role underutilization occurs when employees are allowed to use only a few of their skills and abilities, even though they are required to make heavy use of them. The most prevalent characteristic of role underutilization is monotony, where the worker performs the same routine task (or set of tasks) over and over. Other situations that make for underutilization include total dependence on machines for determining work pace and sustained positional or postural constraint. Several studies have found that underutilization often leads to low self-esteem, low life satisfaction, and increased frequency of nervous complaints and symptoms .
Both role overload and role underutilization have been shown to influence psychological and physiological reactions to the job. The inverted U-shaped relationship between the extent of role utilization and stress is shown in Figure \(\PageIndex{3}\). As shown, the least stress is experienced at that point where an employee’s abilities and skills are in balance with the requirements of the job. This is where performance should be highest. Employees should be highly motivated and should have high energy levels, sharp perception, and calmness. (Recall that many of the current efforts to redesign jobs and improve the quality of work are aimed at minimizing overload or underutilization in the workplace and achieving a more suitable balance between abilities possessed and skills used on the job.) When employees experience underutilization, boredom, decreased motivation, apathy, and absenteeism will be more likely. Role overload can lead to such symptoms as insomnia, irritability, increased errors, and indecisiveness.
Taken together, occupation and role processes represent a sizable influence on whether or not an employee experiences high stress levels. One job where the profession and its required roles almost guarantee significant stress is air traffic control. Consider for a moment whether you would want to have this job.
Expanding around the globe
Are the Japanese Working Themselves to Death?
Karoshi literally means death from overwork, and unofficial estimates are that as many people die each year from karoshi as from traffic accidents in Japan—approximately 10,000. In 2016, the legal claims of karoshi rose to a record high of 1,456 according to government figures. Additionally, just under 2,000 suicides linked to work-related causes were reported. In October 2017, the latest employee death that shook the media was 31-year-old journalist Miwa Sado, and before that 24-year-old Matsui Takahashi, an employee working at Dentsu advertising agency, leapt from the roof on Christmas Day 2015.
These incidents are just two of many that occur more frequently in Japan due to the culture of overtime and stress within the work environment. Each of these women logged over 100 hours of overtime over the course of one month. Often the causes of death include heart failure, stroke, and suicide due to the stress, lack of sleep, and sleep deprivation that is caused by being overworked. Takahashi posted on Twitter, “It’s 4 a.m.  I’m so tired.” Soon after her death, the president of Dentsu resigned from his post.
Many reports suggest that performance reviews are marked negatively for those that don’t work lots of overtime, while others suggest employees must strive to make good impressions on their bosses, and staying late or working extra is perceived as loyalty to their jobs and companies.
The Japanese government has taken strides since the two incidents to implement policies to help to combat karoshi for good. One attempt implemented in 2016 is A Premium Friday plan, where Japanese workers are allowed the chance to leave at 3 p.m. on the last Friday of each month. This has only made some employees busier because some companies have organized their monthly finances to hit sales goals before the end of the month. Little success has been seen from this initiative. One Tokyo-best IT Service company forced employees to wear purple capes on the third Wednesday of the month if they worked late, which was a very bold and visual tactic to showcase the “working late is not cool” vibe. This shaming tactic worked, decreasing the overtime worked by 50 percent. Some companies have implemented individual changes such as breakfast offerings and allowing time off as needed.
Changing the Japanese work culture will take time. Although these small changes have not made a large impact yet, the discussion is widening, and workplaces are becoming more aware of the need for drastic changes in policy to counteract the growing issue of stress in the workplace.
Questions:
- What considerations should a manager take before implementing changes to a work environment and policies when managing a global team?
- What environmental and cultural factors can affect an employee’s work ethic and their level of stress in their workday?
Sources:
C. Weller, “Japan is facing a 'death by overwork' problem — here's what it's all about,” Business Insider , October 8, 2017, https://www.businessinsider.com/what...7-10?r=UK&IR=T
E. Warnock, “Japan by the Numbers: ‘Karoshi’,” Tokyo Review , October 12, 2017, http://www.tokyoreview.net/2017/10/j...oshi-overwork/
(Why Japanese Workers Keep Working Themselves to Death,” CBS News, October 20, 2017, https://www.cbsnews.com/news/karoshi...nese-overwork/
D. Demetriou, “Death for Overworking Claims Hit Record High in Japan,” The Telegraph, April 4, 2016, https://www.telegraph.co.uk/news/201...high-in-japan/
D. Hurst, “First step in changing Japan's workaholic culture: less overtime,” NBC News, January 8, 2018, https://www.nbcnews.com/news/world/f...ertime-n833051 .
Personal Influences on Stress
The second major influence on job-related stress can be found in the employees themselves. As such, we will examine three individual-difference factors as they influence stress at work: (1) personal control, (2) Type A personality, and (3) rate of life change.
Personal Control
To begin with, we should acknowledge the importance of personal control as a factor in stress. Personal control represents the extent to which an employee actually has control over factors affecting effective job performance. If an employee is assigned a responsibility for something (landing an airplane, completing a report, meeting a deadline) but is not given an adequate opportunity to perform (because of too many planes, insufficient information, insufficient time), the employee loses personal control over the job and can experience increased stress. Personal control seems to work through the process of employee participation. That is, the more employees are allowed to participate in job-related matters, the more control they feel for project completion. On the other hand, if employees’ opinions, knowledge, and wishes are excluded from organizational operations, the resulting lack of participation can lead not only to increased stress and strain, but also to reduced productivity.
The importance of employee participation in enhancing personal control and reducing stress is reflected in the French and Caplan study discussed earlier. After a major effort to uncover the antecedents of job-related stress, these investigators concluded:
“Since participation is also significantly correlated with low role ambiguity, good relations with others, and low overload, it is conceivable that its effects are widespread, and that all the relationships between these other stresses and psychological strain can be accounted for in terms of how much the person participates. This, in fact, appears to be the case. When we control or hold constant, through statistical analysis techniques, the amount of participation a person reports, then the correlations between all the above stresses and job satisfaction and job-related threat drop quite noticeably. This suggests that low participation generates these related stresses, and that increasing participation is an efficient way of reducing many other stresses which also lead to psychological strain.”
On the bases of this and related studies, we can conclude that increased participation and personal control over one’s job is often associated with several positive outcomes, including lower psychological strain, increased skill utilization, improved working relations, and more-positive attitudes. These factors, in turn, contribute toward higher productivity. These results are shown in Figure \(\PageIndex{3}\).
Related to the issue of personal control—indeed, moderating its impact—is the concept of locus of control . It will be remembered that some people have an internal locus of control, feeling that much of what happens in their life is under their own control. Others have an external locus of control, feeling that many of life’s events are beyond their control. This concept has implications for how people respond to the amount of personal control in the work environment. That is, internals are more likely to be upset by threats to the personal control of surrounding events than are externals. Recent evidence indicates that internals react to situations over which they have little or no control with aggression—presumably in an attempt to reassert control over ongoing events. On the other hand, externals tend to be more resigned to external control, are much less involved in or upset by a constrained work environment, and do not react as emotionally to organizational stress factors. Hence, locus of control must be recognized as a potential moderator of the effects of personal control as it relates to experienced stress.
Type A Personality
Research has focused on what is perhaps the single most dangerous personal influence on experienced stress and subsequent physical harm. This characteristic was first introduced by Friedman and Rosenman and is called Type A personality . Type A and Type B personalities are felt to be relatively stable personal characteristics exhibited by individuals. Type A personality is characterized by impatience, restlessness, aggressiveness, competitiveness, polyphasic activities (having many “irons in the fire” at one time), and being under considerable time pressure. Work activities are particularly important to Type A individuals, and they tend to freely invest long hours on the job to meet pressing (and recurring) deadlines. Type B people, on the other hand, experience fewer pressing deadlines or conflicts, are relatively free of any sense of time urgency or hostility, and are generally less competitive on the job. These differences are summarized in Table \(\PageIndex{3}\).
| Profiles of Type A and Type B Personalities | |
|---|---|
| Type A | Type B |
| Highly competitive | Lacks intense competitiveness |
| “Workaholic” | Work only one of many interests |
| Intense sense of urgency | More deliberate time orientation |
| Polyphasic behavior | Does one activity at a time |
| Strong goal-directedness | More moderate goal-directedness |
Type A personality is frequently found in managers. Indeed, one study found that 60 percent of managers were clearly identified as Type A, whereas only 12 percent were clearly identified as Type B. It has been suggested that Type A personality is most useful in helping someone rise through the ranks of an organization.
The role of Type A personality in producing stress is exemplified by the relationship between this behavior and heart disease. Rosenman and Friedman studied 3,500 men over an 8 1/2-year period and found Type A individuals to be twice as prone to heart disease, five times as prone to a second heart attack, and twice as prone to fatal heart attacks when compared to Type B individuals. Similarly, Jenkins studied over 3,000 men and found that of 133 coronary heart disease sufferers, 94 were clearly identified as Type A in early test scores. The rapid rise of women in managerial positions suggests that they, too, may be subject to this same problem. Hence, Type A behavior very clearly leads to one of the most severe outcomes of experienced stress.
One irony of Type A is that although this behavior is helpful in securing rapid promotion to the top of an organization, it may be detrimental once the individual has arrived. That is, although Type A employees make successful managers (and salespeople), the most successful top executives tend to be Type B. They exhibit patience and a broad concern for the ramifications of decisions. As Dr. Elmer Green, a Menninger Foundation psychologist who works with executives, notes, “This fellow—the driving A—can’t relax enough to do a really first-rate job, at the office or at home. He gets to a level that dogged work can achieve, but not often to the pinnacle of his business or profession, which requires sober, quiet, balanced reasoning.” The key is to know how to shift from Type A behavior to Type B.
How does a manager accomplish this? The obvious answer is to slow down and relax. However, many Type A managers refuse to acknowledge either the problem or the need for change, because they feel it may be viewed as a sign of weakness. In these cases, several small steps can be taken, including scheduling specified times every day to exercise, delegating more significant work to subordinates, and eliminating optional activities from the daily calendar. Some companies have begun experimenting with retreats, where managers are removed from the work environment and engage in group psychotherapy over the problems associated with Type A personality. Initial results from these programs appear promising. Even so, more needs to be done if we are to reduce job-related stress and its serious health implications.
Rate of Life Change
A third personal influence on experienced stress is the degree to which lives are stable or turbulent. A long-term research project by Holmes and Rahe has attempted to document the extent to which rate of life change generates stress in individuals and leads to the onset of disease or illness. As a result of their research, a variety of life events were identified and assigned points based upon the extent to which each event is related to stress and illness.
The death of a spouse was seen as the most stressful change and was assigned 100 points. Other events were scaled proportionately in terms of their impact on stress and illness. It was found that the higher the point total of recent events, the more likely it is that the individual will become ill. Apparently, the influence of life changes on stress and illness is brought about by the endocrine system. This system provides the energy needed to cope with new or unusual situations. When the rate of change surpasses a given level, the system experiences overload and malfunctions. The result is a lowered defense against viruses and disease.
Concept check
- What impact do different occupations have of the stress levels of workers in those jobs?
- What are Type A and Type B personalities and how does stress affect each personality type?


3.3: Perception Process - Part 3 (Interpretation)
Interpretation
Once we have selected what to pay attention to, we organize it into a preconceived pattern or category, and then we interpret its meaning. This is essentially the outcome of our perceptions. Though all the stages in this process are important, this last stage will serve as the tangible consequence of this process. We can also note here that, as we have learned so far about perceptions, our brain is essentially trying to make sense of the world around us. One way to maintain simplicity is to confirm what we already think we know. Changing our minds can be challenging, painful, and/or complicated. Therefore, we will start with confirmation bias.
Confirmation Bias
Confirmation bias is our tendency to attend to evidence that supports preconceived notions while ignoring or disregarding evidence that is contrary to our desired reality (Gray, 2010). This can make it challenging for us to see things as they really are; instead, we see things as we are.
Let’s say you hear a rumor that your best friend, who is married, is having an affair. You know your friend. He is a great guy, a loving husband, and a devoted father. You dismiss the rumor. Of course, you could see why it seems like he might be texting more or missing regularly scheduled get-togethers, and yes, he seems to be a bit distant. But you know your friend has been very busy. A mutual friend then shows you a picture on a social media platform that seems to be your best friend and a person other than his spouse. You respond with denial and even get angry at others who ask you to talk to him, or approach him about it. Your friend would never engage in an affair. You start to look for cues to confirm your stance. He did say work was picking up; he is probably dealing with a lot of emails and meetings related to that. He tells you he has a friend from college in town and you find comfort in believing that is probably who is in the picture with him on social media.
In this scenario, your interpretation might be viewed as noble or loyal—but in other scenarios, you may be confirming biases that are harmful or inaccurate, like stereotypes, preconceived opinions, or assumptions.
As we move through this stage of the perception process, let’s continue to consider confirmation bias, noting its power to reinforce our preconceived notions, while at the same time avoiding anything that would challenge those. Let us continue to be aware of our brain’s desire to be right, even at the cost of disregarding facts.
So let us dive into the most prominent facet of interpretation: making attributions.
Attributions
Attribution is defined as “the interpretive process by which people make judgments about the causes of their own behavior and the behavior of others” (Heider, 1958, para. 3). When we engage in interpersonal communication, how we interpret messages directly influences the quality of the interaction as well as the relationship. In this section, we explore the psychological tendencies associated with perception and how they affect our communication interactions.
Fundamental Attribution Error
Fundamental attribution error is the tendency to attribute others' behavior to internal, rather than external, factors (Ross, 1977). For example, Sam is in a hurry to get to work on time and accidently blocks wheelchair access to a sidewalk when they park. When Sam gets to their car after a long shift, they see a ticket. Their initial reaction is “Those parking jerks have nothing better to do than to give me a ticket. They love ruining people’s day!” Now, let’s break this down.  There is no acknowledgement of a parking violation, the hurry to make it to work on time, or the possible inconvenience to others. We could continue and consider that the officer, while noting the violation, labeled Sam as selfish and not a law-abiding citizen. Say that a person in a wheelchair was unable to access the sidewalk and thought of Sam as a person who is uncaring of those with physical limitations. These attributions happen quickly, and they attribute a person's behavior to who that person is, rather than to external factors. Some of these assumptions—or all of them—could be true. However, we can see how miscommunication and conflict could arise quite quickly if we used attributions as the basis for our interactions with others.
Self-Serving Bias
Have you ever been driving on the freeway when your lane suddenly merges with another and you hear a loud honk? Whoa, that car came from out of nowhere! “Geeze,” you think. “Calm down, everyone is fine.” You may find yourself feeling overwhelmingly frustrated that someone got so upset when you didn’t see them in your mirrors.   The hypocrisy of the situation is most likely sinking in already.
Self-serving bias is essentially an attribution process that we engage in to portray ourselves in the most desirable light. Although research shows that we do this almost effortlessly for ourselves, we do not offer those same grace so easily to others.
So how does self-serving bias work, exactly? We can start by understanding where we likely place blame for undesirable behavior. Research shows us that when we are the perpetrators of undesirable behavior, we will likely place blame on external attributions (we are tired, it was an accident, it happened because someone does not like us). Conversely, when we are the victims of undesirable behavior, we place blame on the internal attributions of others (that is their character, they are inconsiderate, they did it on purpose). This was illustrated in research by Baumeister, Stillwell, and Wotman (1990), in which participants were asked to describe an experience when they angered someone else (i.e., when they were the perpetrator of an undesirable behavior) and then asked to describe an experience where someone angered them (i.e., when they were a victim of the undesirable behavior). As you might imagine, participants were quick to identify situational factors, and external attributions, as the source of their own undesirable behavior, asserting that their actions caused no lasting harm to the other. However, when describing the undesirable behavior of another, in which they were a victim, participants often cited character flaws and internal attributions, and noted the lasting damage of the interaction. These findings are quite significant if put into the context of the harm that attribution biases can have on interpersonal relationships. A good reminder here can be to check perceptions, acknowledge biases, and extend some grace to those we interact with.
Halo and Horn Effects
We have learned so far that our brains are wired to conserve energy and opt for simplicity. We also learned that initial interactions (first impressions) hold strong and for a long time. So, what happens when our first perceptions of someone are positive? What happens when they are negative?  In fact, this occurrence is so prominent that researchers have coined the terms halo and horn effects to identify them as interpersonal communication phenomena. The halo effect occurs when initial positive perceptions lead us to view later interactions as positive (Hargie, 2011). The horn effect occurs when initial negative perceptions lead us to view later interactions as negative (Hargie, 2011). Just as the metaphor suggests, you can imagine these initial interactions as creating mini halos or horns above those around you, guiding your interpretations of subsequent interactions (discussed in the section on the primacy and regency effects on page 3.2 ).
Halo Effect
Let’s say your sister wants the family to meet her new boyfriend, Damien.  Your sister and Damien show up right on time. Damien brings flowers for your mom a bottle of wine to share and immediately asks if he should remove his shoes because they are wet from the rain outside. He introduces himself to everyone in the room and offers to help cook and set up for dinner. Damien has earned himself a halo .
The next time you meet Damien, he and your sister are running late. "This is so unlike Damien," you think to yourself.   However, for much of the night, Damien is on his phone. That halo will have you thinking he must be busy with work, or you may feel bad that he seems distracted by something else. You think you know who Damien is, based on your initial interaction with him; therefore, any negative interactions after that are attributed to external factors.
Horn Effect
If we flip the script, you could imagine another introduction where your sister and Damien show up late for dinner at your mom’s house. Damien is more reserved or shy with introductions, and perhaps he walks into the house wearing wet shoes. He does not bring anything to contribute to dinner and he certainly does not offer to help. In this scenario, perhaps Damien has earned a horn . In any subsequent meetings, that initial introduction guides your perceptions of Damien’s behavior. Say Damien offers you a hug. You might find this “out of character,” even though you have only met him once. While he is on his phone at dinner, you reconfirm that he is distant, introverted, and not particularly interested in interacting.
You can see how the initial interaction shapes how you perceive future interactions with someone new. Though you may have many subsequent interactions, research shows us that it takes some time to shake that halo or horn (Hargie, 2011).
Understanding how perceptions are formed can be a very powerful tool in helping us navigate our interpersonal relationships. Acknowledging our tendencies to make snap judgments might help us pause and reassess how accurate those judgments are.


19.6: Interventions During Birth
By the end of this section, you will be able to:
- Explain the obstetric indications for the use of forceps during birth
- Explain the obstetric indications for the use of the vacuum extractor during birth
- Discuss the nursing care of the person in labor requiring an operative vaginal birth
The use of forceps or vacuum to assist with the birth is considered operative delivery . These deliveries can be difficult for both the laboring person and the fetus. However, in certain situations, the use of these instruments can protect the person or the fetus by expediting delivery.
Obstetric Forceps
The metal instruments placed on the fetal head to rotate the head or assist in delivery of the fetus are called obstetric forceps . The use of forceps during labor is indicated for maternal exhaustion and when the birth must urgently occur, such as when fetal heart rate decelerations are noted. This can be an alternative to cesarean birth .  They cradle the fetal skull to apply traction, rotation, flexion, and extension, as seen in Figure 19.12 (Shabib & Black, 2022). Indications for forceps birth include nonreassuring fetal heart rate , prolonged second stage of labor , and delivery of the head after a breech presentation . Forceps birth can be attempted only if the cervix is completely dilated, the membranes are ruptured, the fetal head is low in the pelvis, and the provider does not suspect cephalopelvic disproportion (Shabib & Black, 2022). Complications to the birthing person when obstetric forceps are used include lacerations of the vagina and cervix, pelvic hematomas , urethral and bladder injury, rupture of the uterus, and posttraumatic stress disorder (PTSD). Fetal complications include facial lacerations and nerve damage, cephalohematoma s, skull fractures, intracranial hemorrhage , and seizures (Shabib & Black, 2022).
When the health-care provider makes the decision and obtains consent from the birthing person to use forceps to deliver the fetus, the nurse performs several actions. The nurse assists the person into the lithotomy position and ensures that the bladder is emptied. If the person has an epidural, the nurse can call the anesthesia provider to ensure the person has adequate pain relief. The neonatal team should be in the room in case of newborn complications.
Consent for Operative Delivery
Upon admission, the laboring person signs consent forms for birth. Because an operative delivery is a deviation from normal, informed consent should be requested and given by the laboring person for use of forceps or vacuum. The health-care provider should explain why the operative delivery is necessary, the risks and benefits of the procedure, and how the procedure will be performed. The provider should allow time for questions and ensure shared decision making. The health-care provider is responsible for providing this information in a nonbiased way. For consent, the person must have the mental capacity to understand and make that decision.
Vacuum Extractor
A vacuum extractor is a device used to help deliver the fetal head during the second stage of labor. The vacuum device usually features a soft, silicone cup that fits onto the fetal head. A pump and gauge attach to the cup to apply the proper amount of suction. Once the vacuum is applied to the fetal head, traction is placed to assist the birth while the birthing person is pushing. Indications for a vacuum-assisted delivery are the same as for forceps-assisted delivery. Contraindications to the use of the vacuum include face or breech presentation, cephalopelvic disproportion, fetal head anomaly, preterm fetus, or fetal bleeding risk (Shabib & Black, 2022). Complications include neonatal injury, including superficial scalp markings, retinal hemorrhage, cephalohematoma, subgaleal hematoma, and intracranial hemorrhage (Shabib & Black, 2022). The vacuum can cause perineal and vaginal lacerations to the laboring person.
When the provider has indicated a need to deliver the fetus using the vacuum extractor and consent has been obtained, the nurse assists the person into stirrups. The vacuum system is checked for leaks. The cup is placed on the fetal head, and the vacuum pressure is increased during the contraction. The pressure is decreased between contractions. The nurse ensures the pediatric team is available for newborn complications. Figure 19.13 demonstrates the application of the vacuum.


3.7: James Joyce (1882-1941)
James Joyce was born in Dublin into a middle-class, Catholic family. Joyce’s father John was a property tax collector whose alcoholism and consequent unreliability steadily reduced the family’s income and social standing. Joyce’s education became tenuous when, due to financial uncertainty, he was removed from Clongowes Wood College. He studied briefly at Christian Brothers O’Connell School before finding a place at Belvedere College, a Jesuit school. He then studied modern languages at University College Dublin where he immersed himself in literature and theater.
In 1901, Joyce and his partner Nora Barnacle left Ireland to live in Trieste, where Joyce taught English; they also lived in Zurich and Paris. Although he lived on the Continent, Joyce’s writing consistently drew from his life in Dublin. His own intellectual and artistic growth, his school mates, roommates, acquaintances, and family members shaped and gave focus to his work, as did conflicts arising from Joyce’s views on Roman Catholicism and Irish self-governance.
In 1912, he returned briefly to Ireland to see to the publication of The Dubliners (1914), a collection of short stories. Joyce’s short stories redefined the traditional short story narrative form by “replacing” the rising-action, climax, and aftermath of Freytag’s triangle with Wordsworthian spots of time, or what Joyce termed epiphanies. Its “action” reveals hidden motivations, motivations that are deeper than the “real” situations the stories describe, motivations that lie deep in the unconscious. Joyce’s realism ultimately opens up into the human psyche.
Through the financial support of Harriet Shaw Weaver (1876-1961), to whom the American writer Ezra Pound (1885-1972) introduced Joyce while in Zurich, Joyce published Portrait of the Artist as a Young Man , revised from an earlier draft entitled Portrait of the Artist , and worked on his monumental novel Ulysses (1922).
Despite financial strain, worsening eyesight, and the mental instability of his and Nora’s daughter Lucia, Joyce continued to experiment with writing, gaining literary renown among an important circle of intellectuals and artists. Harriet Shaw Weaver and Maria McDonald Jolas (1893-1987) and Eugene Jolas (1894- 1952) supported Joyce as he moved through Ulysses to Finnegan’s Wake (1939).
Ulysses , a novel that used almost every extant genre and style of writing and reading, reshaped what twentieth-century (and twenty-first century) novels would become. It used for a structural element what T. S. Eliot called the mythic method, or analog: Odysseus’s return from Troy to Ithaka. The book maintains a tension between this mythic analogue and realism. The novel as a genre highlights realism. In Ulysses , realism seems uppermost, particularly as critics have identified actual events and people from Dublin who appear in the novel; yet, the analog breaks through. Its use of symbolism ultimately casts doubt on a concrete, logical sense of history, casts doubt on linear time so that reality becomes protean.
Finnegan’s Wake furthers these experiments with style by experimenting with language, structure, subject, and meaning. Finnegan’s Wake hoists the novel as genre entirely beyond the “familiar” into territory that is still being “explored.”
Joyce died in Zurich from surgical complications after a perforated ulcer.
3.7.1: “Araby”
North Richmond Street, being blind, was a quiet street except at the hour when the Christian Brothers’ School set the boys free. An uninhabited house of two storeys stood at the blind end, detached from its neighbours in a square ground. The other houses of the street, conscious of decent lives within them, gazed at one another with brown imperturbable faces.
The former tenant of our house, a priest, had died in the back drawing-room. Air, musty from having been long enclosed, hung in all the rooms, and the waste room behind the kitchen was littered with old useless papers. Among these I found a few paper-covered books, the pages of which were curled and damp: The Abbot, by Walter Scott, The Devout Communicant and The Memoirs of Vidocq. I liked the last best because its leaves were yellow. The wild garden behind the house contained a central apple-tree and a few straggling bushes under one of which I found the late tenant’s rusty bicycle-pump. He had been a very charitable priest; in his will he had left all his money to institutions and the furniture of his house to his sister.
When the short days of winter came dusk fell before we had well eaten our dinners. When we met in the street the houses had grown sombre. The space of sky above us was the colour of ever-changing violet and towards it the lamps of the street lifted their feeble lanterns. The cold air stung us and we played till our bodies glowed. Our shouts echoed in the silent street. The career of our play brought us through the dark muddy lanes behind the houses where we ran the gauntlet of the rough tribes from the cottages, to the back doors of the dark dripping gardens where odours arose from the ashpits, to the dark odorous stables where a coachman smoothed and combed the horse or shook music from the buckled harness. When we returned to the street light from the kitchen windows had filled the areas. If my uncle was seen turning the corner we hid in the shadow until we had seen him safely housed. Or if Mangan’s sister came out on the doorstep to call her brother in to his tea we watched her from our shadow peer up and down the street. We waited to see whether she would remain or go in and, if she remained, we left our shadow and walked up to Mangan’s steps resignedly. She was waiting for us, her figure defined by the light from the half-opened door. Her brother always teased her before he obeyed and I stood by the railings looking at her. Her dress swung as she moved her body and the soft rope of her hair tossed from side to side.
Every morning I lay on the floor in the front parlour watching her door. The blind was pulled down to within an inch of the sash so that I could not be seen. When she came out on the doorstep my heart leaped. I ran to the hall, seized my books and followed her. I kept her brown figure always in my eye and, when we came near the point at which our ways diverged, I quickened my pace and passed her. This happened morning after morning.
Her image accompanied me even in places the most hostile to romance. On Saturday evenings when my aunt went marketing I had to go to carry some of the parcels. We walked through the flaring streets, jostled by drunken men and bargaining women, amid the curses of labourers, the shrill litanies of shop-boys who stood on guard by the barrels of pigs’ cheeks, the nasal chanting of streetsingers, who sang a come-all-you about O’Donovan Rossa, or a ballad about the troubles in our native land. These noises converged in a single sensation of life for me: I imagined that I bore my chalice safely through a throng of foes. Her name sprang to my lips at moments in strange prayers and praises which I myself did not understand. My eyes were often full of tears (I could not tell why) and at times a flood from my heart seemed to pour itself out into my bosom. I thought little of the future. I did not know whether I would ever speak to her or not or, if I spoke to her, how I could tell her of my confused adoration. But my body was like a harp and her words and gestures were like fingers running upon the wires.
One evening I went into the back drawing-room in which the priest had died. It was a dark rainy evening and there was no sound in the house. Through one of the broken panes I heard the rain impinge upon the earth, the fine incessant needles of water playing in the sodden beds. Some distant lamp or lighted window gleamed below me. I was thankful that I could see so little. All my senses seemed to desire to veil themselves and, feeling that I was about to slip from them, I pressed the palms of my hands together until they trembled, murmuring: “O love! O love!” many times.
At last she spoke to me. When she addressed the first words to me I was so confused that I did not know what to answer. She asked me was I going to Araby. I forgot whether I answered yes or no. It would be a splendid bazaar, she said she would love to go.
“And why can’t you?” I asked.
While she spoke she turned a silver bracelet round and round her wrist. She could not go, she said, because there would be a retreat that week in her convent. Her brother and two other boys were fighting for their caps and I was alone at the railings. She held one of the spikes, bowing her head towards me. The light from the lamp opposite our door caught the white curve of her neck, lit up her hair that rested there and, falling, lit up the hand upon the railing. It fell over one side of her dress and caught the white border of a petticoat, just visible as she stood at ease.
“It’s well for you,” she said.
“If I go,” I said, “I will bring you something.”
What innumerable follies laid waste my waking and sleeping thoughts after that evening! I wished to annihilate the tedious intervening days. I chafed against the work of school. At night in my bedroom and by day in the classroom her image came between me and the page I strove to read. The syllables of the word Araby were called to me through the silence in which my soul luxuriated and cast an Eastern enchantment over me. I asked for leave to go to the bazaar on Saturday night. My aunt was surprised and hoped it was not some Freemason affair. I answered few questions in class. I watched my master’s face pass from amiability to sternness; he hoped I was not beginning to idle. I could not call my wandering thoughts together. I had hardly any patience with the serious work of life which, now that it stood between me and my desire, seemed to me child’s play, ugly monotonous child’s play.
On Saturday morning I reminded my uncle that I wished to go to the bazaar in the evening. He was fussing at the hallstand, looking for the hat-brush, and answered me curtly:
“Yes, boy, I know.”
As he was in the hall I could not go into the front parlour and lie at the window. I felt the house in bad humour and walked slowly towards the school. The air was pitilessly raw and already my heart misgave me.
When I came home to dinner my uncle had not yet been home. Still it was early. I sat staring at the clock for some time and, when its ticking began to irritate me, I left the room. I mounted the staircase and gained the upper part of the house. The high cold empty gloomy rooms liberated me and I went from room to room singing. From the front window I saw my companions playing below in the street. Their cries reached me weakened and indistinct and, leaning my forehead against the cool glass, I looked over at the dark house where she lived. I may have stood there for an hour, seeing nothing but the brown-clad figure cast by my imagination, touched discreetly by the lamplight at the curved neck, at the hand upon the railings and at the border below the dress.
When I came downstairs again I found Mrs. Mercer sitting at the fire. She was an old garrulous woman, a pawnbroker’s widow, who collected used stamps for some pious purpose. I had to endure the gossip of the tea-table. The meal was prolonged beyond an hour and still my uncle did not come. Mrs. Mercer stood up to go: she was sorry she couldn’t wait any longer, but it was after eight o’clock and she did not like to be out late, as the night air was bad for her. When she had gone I began to walk up and down the room, clenching my fists. My aunt said:
“I’m afraid you may put off your bazaar for this night of Our Lord.”
At nine o’clock I heard my uncle’s latchkey in the halldoor. I heard him talking to himself and heard the hallstand rocking when it had received the weight of his overcoat. I could interpret these signs. When he was midway through his dinner I asked him to give me the money to go to the bazaar. He had forgotten.
“The people are in bed and after their first sleep now,” he said. I
did not smile. My aunt said to him energetically:
“Can’t you give him the money and let him go? You’ve kept him late enough as it is.”
My uncle said he was very sorry he had forgotten. He said he believed in the old saying: “All work and no play makes Jack a dull boy.” He asked me where I was going and, when I had told him a second time he asked me did I know The Arab’s Farewell to his Steed. When I left the kitchen he was about to recite the opening lines of the piece to my aunt.
I held a florin tightly in my hand as I strode down Buckingham Street towards the station. The sight of the streets thronged with buyers and glaring with gas recalled to me the purpose of my journey. I took my seat in a third-class carriage of a deserted train. After an intolerable delay the train moved out of the station slowly. It crept onward among ruinous houses and over the twinkling river. At Westland Row Station a crowd of people pressed to the carriage doors; but the porters moved them back, saying that it was a special train for the bazaar. I remained alone in the bare carriage. In a few minutes the train drew up beside an improvised wooden platform. I passed out on to the road and saw by the lighted dial of a clock that it was ten minutes to ten. In front of me was a large building which displayed the magical name.
I could not find any sixpenny entrance and, fearing that the bazaar would be closed, I passed in quickly through a turnstile, handing a shilling to a weary-looking man. I found myself in a big hall girdled at half its height by a gallery. Nearly all the stalls were closed and the greater part of the hall was in darkness. I recognised a silence like that which pervades a church after a service. I walked into the centre of the bazaar timidly. A few people were gathered about the stalls which were still open. Before a curtain, over which the words Café Chantant were written in coloured lamps, two men were counting money on a salver. I listened to the fall of the coins.
Remembering with difficulty why I had come I went over to one of the stalls and examined porcelain vases and flowered tea-sets. At the door of the stall a young lady was talking and laughing with two young gentlemen. I remarked their English accents and listened vaguely to their conversation.
“O, I never said such a thing!”
“O, but you did!”
“O, but I didn’t!”
“Didn’t she say that?”
“Yes. I heard her.”
“O, there’s a … fib!”
Observing me the young lady came over and asked me did I wish to buy anything. The tone of her voice was not encouraging; she seemed to have spoken to me out of a sense of duty. I looked humbly at the great jars that stood like eastern guards at either side of the dark entrance to the stall and murmured:
“No, thank you.”
The young lady changed the position of one of the vases and went back to the two young men. They began to talk of the same subject. Once or twice the young lady glanced at me over her shoulder.
I lingered before her stall, though I knew my stay was useless, to make my interest in her wares seem the more real. Then I turned away slowly and walked down the middle of the bazaar. I allowed the two pennies to fall against the sixpence in my pocket. I heard a voice call from one end of the gallery that the light was out. The upper part of the hall was now completely dark.
Gazing up into the darkness I saw myself as a creature driven and derided by vanity; and my eyes burned with anguish and anger.


1.3A: Basic Microbiology
- Evaluate the science of basic microbiology; understand the fundamental aspects of microbiology.
Microbiology is the study of microscopic organisms (microbes), which are defined as any living organism that is either a single cell (unicellular), a cell cluster, or has no cells at all (acellular). This includes eukaryotes, such as fungi and protists, and prokaryotes. Viruses and prions, though not strictly classed as living organisms, are also studied.
Microbiology typically includes the study of the immune system, or immunology. Generally, immune systems interact with pathogenic microbes; these two disciplines often intersect which is why many colleges offer a paired degree such as “Microbiology and Immunology. ”
Microbiology is a broad term which includes virology, mycology, parasitology, bacteriology, immunology, and other branches. A microbiologist is a specialist in microbiology and these related topics. Microbiological procedures usually must be aseptic and use a variety of tools such as light microscopes with a combination of stains and dyes. As microbes are absolutely required for most facets of human life (including the air we breathe and the food we eat) and are potential causes of many human diseases, microbiology is paramount for human society.
Research in the microbiology field is expanding, and in the coming years, we should see the demand for microbiologists in the workforce increase. It is estimated that only about one percent of the microorganisms present in a given environmental sample are culturable and the number of bacterial cells and species on Earth is still not possible to be determined. Recent estimates indicate that this number might be extremely high at five to the power of thirty. Although microbes were directly observed over three hundred years ago, the precise determination, quantitation, and description of its functions is far from complete, given the overwhelming diversity detected by genetic and culture-independent means.
Key Points
- Microbiology focuses on organisms that are very small using various tools, which is a process done by microbiologists.
- As microbes are essential for human life and as microbes can cause human diseases, microbiology is therefore very important.
- The numbers of individual microbes and the number of microbes in and on the earth is staggering in proportions.
Key Terms
- quantitation : The process of quantitating.
- immunology : The branch of medicine that studies the body’s immune system.
- culturable : Able to be cultured (grown in a suitable environment).


6.3: The Heisenberg Uncertainty Principle
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Learning Objectives
By the end of this section, you will be able to:
- Describe the physical meaning of the position-momentum uncertainty relation
- Explain the origins of the uncertainty principle in quantum theory
- Describe the physical meaning of the energy-time uncertainty relation
Heisenberg’s uncertainty principle is a key principle in quantum mechanics. Very roughly, it states that if we know everything about where a particle is located (the uncertainty of position is small), we know nothing about its momentum (the uncertainty of momentum is large), and vice versa. Versions of the uncertainty principle also exist for other quantities as well, such as energy and time. We discuss the momentum-position and energy-time uncertainty principles separately.
Momentum and Position
To illustrate the momentum-position uncertainty principle, consider a free particle that moves along the x -direction. The particle moves with a constant velocity \(u\) and momentum \(p = mu\). According to de Broglie’s relations, \(p = \hbar k\) and \(E = \hbar \omega\). As discussed in the previous section, the wavefunction for a free particle is given by
\[ \begin{align*} \psi_k(x,t) &= A[\cos \, (\omega t - kx) - i \, \sin \, (\omega t - kx)] \\[4pt] &= A \, e^{-i(\omega t - kx)} \\[4pt] &= A \, e^{-i(\omega t - kx)} \\[4pt] &=A\, e^{-i\omega t} e^{ikx} \end{align*} \nonumber \]
and the probability density \(|\psi_k (x,t)|^2 = A^2\) is uniform and independent of time. The particle is equally likely to be found anywhere along the x -axis but has definite values of wavelength and wave number, and therefore momentum. The uncertainty of position is infinite (we are completely uncertain about position) and the uncertainty of the momentum is zero (we are completely certain about momentum). This account of a free particle is consistent with Heisenberg’s uncertainty principle.
Similar statements can be made of localized particles. In quantum theory, a localized particle is modeled by a linear superposition of free-particle (or plane-wave) states called a wave packet . An example of a wave packet is shown in Figure \(\PageIndex{1}\). A wave packet contains many wavelengths and therefore by de Broglie’s relations many momenta—possible in quantum mechanics! This particle also has many values of position, although the particle is confined mostly to the interval \(\Delta x\). The particle can be better localized (\(\Delta x\) can be decreased) if more plane-wave states of different wavelengths or momenta are added together in the right way (\(\Delta p\) is increased). According to Heisenberg, these uncertainties obey the following relation.
Definition: The Heisenberg’s Uncertainty Principle
The product of the uncertainty in position of a particle and the uncertainty in its momentum can never be less than one-half of the reduced Planck constant:
\[\Delta x \Delta p \geq \dfrac{\hbar}{2}. \label{Heisen} \]
This relation expresses Heisenberg’s uncertainty principle. It places limits on what we can know about a particle from simultaneous measurements of position and momentum. If \(\Delta x\) is large, \(\Delta p\) is small, and vice versa. Equation \ref{Heisen} can be derived in a more advanced course in modern physics. Reflecting on this relation in his work The Physical Principles of the Quantum Theory , Heisenberg wrote “Any use of the words ‘position’ and ‘velocity’ with accuracy exceeding that given by [the relation] is just as meaningless as the use of words whose sense is not defined.”
Note that the uncertainty principle has nothing to do with the precision of an experimental apparatus. Even for perfect measuring devices, these uncertainties would remain because they originate in the wave-like nature of matter. The precise value of the product \(\Delta x \Delta p\) depends on the specific form of the wavefunction. Interestingly, the Gaussian function (or bell-curve distribution) gives the minimum value of the uncertainty product:
\[\Delta x \Delta p = \dfrac{\hbar}{2} \nonumber \]
Example \(\PageIndex{1}\): The Uncertainty Principle Large and Small
Determine the minimum uncertainties in the positions of the following objects if their speeds are known with a precision of \(1.0 \times 10^{-3} m/s\):
- an electron and
- a bowling ball of mass 6.0 kg.
Strategy
Given the uncertainty in speed \(\Delta u = 1.0 \times 10^{-3} m/s\), we have to first determine the uncertainty in momentum \(\Delta p = m\Delta u\) and then invert Equation \ref{Heisen} to find the uncertainty in position
\[\Delta x = \dfrac{\hbar}{2\Delta p}. \nonumber \]
Solution
- For the electron: \[\begin{align*} \Delta p &= m\Delta u \\[4pt] &= (9.1 \times 10^{-31} kg)(1.0 \times 10^{-3}m/s) \\[4pt] &= 9.1 \times 10^{-34} kg \cdot m/s,\end{align*} \nonumber \] \[\begin{align*} \Delta x &= \frac{\hbar}{2\Delta p} \\[4pt] &= 5.8 \, cm. \end{align*} \nonumber \]
- For the bowling ball: \[\begin{align*} \Delta p &= m\Delta u \\[4pt] &= (6.0 \, kg)(1.0 \times 10^{-3}m/s) \\[4pt] &= 6.0 \times 10^{-3} kg \cdot m/s, \end{align*} \nonumber \] \[\begin{align*} \Delta x &= \frac{\hbar}{2\Delta p} \\[4pt] &= 8.8 \times 10^{-33}m. \end{align*} \nonumber \]
Significance
Unlike the position uncertainty for the electron, the position uncertainty for the bowling ball is immeasurably small. Planck’s constant is very small, so the limitations imposed by the uncertainty principle are not noticeable in macroscopic systems such as a bowling ball.
Example \(\PageIndex{2}\): Uncertainty and the Hydrogen Atom
Estimate the ground-state energy of a hydrogen atom using Heisenberg’s uncertainty principle. ( Hint : According to early experiments, the size of a hydrogen atom is approximately 0.1 nm.)
Strategy
An electron bound to a hydrogen atom can be modeled by a particle bound to a one-dimensional box of length \(L = 0.1 \, nm\). The ground-state wavefunction of this system is a half wave. This is the largest wavelength that can “fit” in the box, so the wavefunction corresponds to the lowest energy state. Note that this function is very similar in shape to a Gaussian (bell curve) function. We can take the average energy of a particle described by this function ( E ) as a good estimate of the ground state energy (\(E_0\)). This average energy of a particle is related to its average of the momentum squared, which is related to its momentum uncertainty.
Solution
To solve this problem, we must be specific about what is meant by “uncertainty of position” and “uncertainty of momentum.” We identify the uncertainty of position (Δx) with the standard deviation of position (\(σ_x\)), and the uncertainty of momentum (\(Δp\)) with the standard deviation of momentum (\(σ_p\)). For the Gaussian function, the uncertainty product is
\[\sigma_x\sigma_p = \frac{\hbar}{2}, \nonumber \]
where
\[\sigma_x^2 = x^2 - \overline{x}^2 \nonumber \]
and
\[\sigma_p^2 = p^2 - \overline{p}^2.\nonumber \]
The particle is equally likely to be moving left as moving right, so \(\overline{p}^2 = 0\). Also, the uncertainty of position is comparable to the size of the box, so \(\sigma_x = L\). The estimated ground state energy is therefore
\[\begin{align*} E_0 &= E_{Gaussian} \\[4pt] &= \dfrac{\overline{p}^2}{m} \\[4pt] &= \frac{\sigma_p^2}{2m} \\[4pt] &= \frac{1}{2m} \left(\frac{\hbar}{2\sigma_x}\right)^2 \\[4pt] &= \frac{1}{2m} \left(\frac{\hbar}{2L}\right)^2 \\[4pt] &= \frac{\hbar^2}{8mL^2}. \end{align*} \nonumber \]
\[\begin{align*}E_0 &= \dfrac{(\hbar c)^2}{8(mc^2)L^2} \\[4pt] &= \frac{(197.3 \, eV \cdot nm)^2}{8(0.511 \cdot 10^6 eV)(0.1 \, nm)^2} \\[4pt] &= 0.952 \, eV \approx 1 \, eV. \end{align*} \nonumber \]
Multiplying numerator and denominator by \(c^2\) gives
Significance
Based on early estimates of the size of a hydrogen atom and the uncertainty principle, the ground-state energy of a hydrogen atom is in the eV range. The ionization energy of an electron in the ground-state energy is approximately 10 eV, so this prediction is roughly confirmed. ( Note: The product ℏcℏc is often a useful value in performing calculations in quantum mechanics.)
Energy and Time
Another kind of uncertainty principle concerns uncertainties in simultaneous measurements of the energy of a quantum state and its lifetime,
\[\Delta E \Delta t \geq \frac{\hbar}{2} \label{H2} \]
where \(\Delta E\) is the uncertainty in the energy measurement and \(\Delta t\) is the uncertainty in the lifetime measurement. The energy-time uncertainty principle does not result from a relation of the type expressed by Equation \ref{Heisen} for technical reasons beyond this discussion. Nevertheless, the general meaning of the energy-time principle is that a quantum state that exists for only a short time cannot have a definite energy. The reason is that the frequency of a state is inversely proportional to time and the frequency connects with the energy of the state, so to measure the energy with good precision, the state must be observed for many cycles.
To illustrate, consider the excited states of an atom. The finite lifetimes of these states can be deduced from the shapes of spectral lines observed in atomic emission spectra. Each time an excited state decays, the emitted energy is slightly different and, therefore, the emission line is characterized by a distribution of spectral frequencies (or wavelengths) of the emitted photons. As a result, all spectral lines are characterized by spectral widths. The average energy of the emitted photon corresponds to the theoretical energy of the excited state and gives the spectral location of the peak of the emission line. Short-lived states have broad spectral widths and long-lived states have narrow spectral widths.
Example \(\PageIndex{3}\): Atomic Transitions
An atom typically exists in an excited state for about \(\Delta t = 10^{-8} s\). Estimate the uncertainty \(\Delta f\) in the frequency of emitted photons when an atom makes a transition from an excited state with the simultaneous emission of a photon with an average frequency of \(f = 7.1 \times 10^{14} Hz\). Is the emitted radiation monochromatic?
Strategy
We invert Equation \ref{H2} to obtain the energy uncertainty \(\Delta E \approx \hbar /2\Delta t\) and combine it with the photon energy \(E = hf\) to obtain \(\Delta f\). To estimate whether or not the emission is monochromatic, we evaluate \(\Delta f/f\).
Solution
The spread in photon energies is \(\Delta E = h \Delta f\). Therefore,
\[\Delta E \approx \frac{\hbar}{2 \Delta t} \Rightarrow h \Delta t \approx \frac{\hbar}{2 \Delta t} \Rightarrow \Delta f \approx \frac{1}{4\pi \Delta t} = \frac{1}{4\pi (10^{-8}s)} = 8.0 \times 10^6 \, Hz, \nonumber \]
\[\frac{\Delta f}{f} = \frac{8.0 \times 10^6 \, Hz}{7.1 \times 10^{14} \, Hz} = 1.1 \times 10^{-8}. \nonumber \]
Significance
Because the emitted photons have their frequencies within \(1.1 \times 10^{-6}\) percent of the average frequency, the emitted radiation can be considered monochromatic.
Exercise \(\PageIndex{1}\)
A sodium atom makes a transition from the first excited state to the ground state, emitting a 589.0-nm photon with energy 2.105 eV. If the lifetime of this excited state is \(1.6 \times 10^{-8} s\), what is the uncertainty in energy of this excited state? What is the width of the corresponding spectral line?
- Answer
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\(4.1 \times 10^{-8} eV\); \(1.1 \times 10^{-5} nm\)


3.9: Quotient Rule
What about \(\frac{d}{dx} \left( \frac{x}{e^x} \right)\)? Can we just take the derivative of the top and bottom separately, and put them together? Nope, we need a quotient rule .
\(\boxed{\cfrac{d}{dx} \left( \cfrac{f}{g} \right) = \frac{g f' - f g'}{g^2}}\)
Where did this strange formula come from? Some fancy algebra will get you there as the next example shows.
Note that I’m using \(a\) and \(b\) instead of \(f\) and \(g\) right now because we will need \(f\) and \(g\) to mean something else in just a second.
So what can we do? One way it to use the product rule in a strange manner. We are going to apply it to \(\frac{d}{dx} \left( b \cdot \frac{a}{b}\right)\). We set \(f = b\), and \(g = \frac{a}{b}\). We see
\[\begin{align*} \frac{d}{dx} \left( b \cdot \frac{a}{b} \right ) & = f g' + g' f \\ & = b \left( \frac{d}{dx} \frac{a}{b} \right) + \left(\frac{a}{b} \right) \left( \frac{d}{dx} b \right) \\ & = b \left( \frac{d}{dx} \frac{a}{b} \right) + \frac{a b'}{b} \end{align*}\]
But notice that \(\frac{d}{dx} \left(b \cdot \frac{a}{b}\right) = \frac{d}{dx} a = a'\). Hence, we have
\(a' = b \left( \frac{d}{dx} \frac{a}{b}\right) + \frac{a b'}{b}\)
Now we just have to solve for \(\frac{d}{dx} \frac{a}{b}\), and we have a formula for derivatives of quotients!
\[\begin{align*} a' & = b \left( \frac{d}{dx} \frac{a}{b} \right) + \frac{a b'}{b} \\ a' - \frac{a b'}{b} & = b\left( \frac{d}{dx} \frac{a}{b} \right) \\ \frac{1}{b} \left( a' - \frac{a b'}{b} \right) & = \frac{d}{dx} \frac{a}{b} \\ \frac{a'}{b} - \frac{a b'}{b^2} & = \frac{d}{dx} \frac{a}{b} \\ \frac{b a'}{b^2} - \frac{a b'}{b^2} & = \frac{d}{dx} \frac{a}{b} \\ \frac{b a' - a b'}{b^2} & = \frac{d}{dx} \frac{a}{b} \\ \end{align*}\]
If we turn this equation around, it gives the same quotient rule I mentioned earlier:
\(\boxed{\cfrac{d}{dx} \left( \cfrac{a}{b} \right) = \frac{b a' - ab'}{b^2}}\)
This has a cute rhyme to it: “low dee high minus high dee low, over the square of what’s below”. The “low dee high” means \(b a'\), since \(b\) is the “low” and \(a'\) is the “dee high”. Then “minus high dee low” is \(- a b'\). Finally, “over the square of what’s below” is \(b^2\).
Let’s see how it looks applying the quotient rule.
We set \(a = x\) and \(b = e^x\). We see \(a' = 1\), \(b' = e^x\). Using the formula \(\cfrac{d}{dx} \left( \cfrac{a}{b} \right) = \frac{b a' - ab'}{b^2}\), we have
\[\begin{align*} \frac{d}{dx} \left ( \frac{x}{e^x} \right) & = \frac{b a' - ab'}{b^2} \\ & = \frac{(e^x)(1) - (x)(e^x)}{(e^x)^2} \\ & = \frac{e^x (1 - x)}{(e^x)^2} \\ & = \boxed{\frac{1 - x}{e^{x}}} \end{align*}\]
If we simplify and turn \(\frac{x^2}{x}\) into just \(x\), then we have \(\frac{d}{dx} \left( \frac{x^2}{x} \right) = \frac{d}{dx} x = \boxed{1}\). Easy enough.
Using the quotient rule, we set \(a = x^2\) and \(b = x\), with \(a' = 2x\) and \(b = 1\). We have
\[\begin{align*} \frac{d}{dx} \left( \frac{x^2}{x} \right) & = \frac{b a' - a b'}{b^2} \\ & = \frac{(x)(2x) - x^2(1)}{(x)^2} \\ & = \frac{2x^2 - x^2}{x^2} \\ & = \frac{x^2}{x^2} \\ & = \boxed{1} \end{align*}\]
Same thing we got before!
In this case, \(a = x^2 + 2x\) and \(b = \ln(x)\). We have \(a' = 2x + 2\), \(b' = \frac{1}{x}\). Hence we have
\[\begin{align*} \frac{d}{dx} \frac{(x^2 + 2x)}{\ln(x)} & = \frac{b a' - a b'}{b^2} \\ & = \frac{(\ln(x)) (2x + 2) - (x^2 + 2x) \left( \frac{1}{x} \right)}{(\ln x)^2} \\ & = \boxed{\frac{\ln(x)(2x + 2) - (x + 2)}{(\ln x)^2}} \end{align*}\]
This doesn’t really simplify farther, so that’s our answer.
In this case \(a = \sin(x)\) and \(b = x\), so \(a' = \cos(x)\) and \(b' = 1\). Hence
\[\begin{align*} \frac{d}{dx} \frac{\sin(x)}{x} & = \frac{b a' - a b'}{b^2} \\ & = \boxed{\frac{x \cos(x) - \sin(x)}{x^2}}. \end{align*}\]


15.1: Unit 2 Overview and Objectives
Overview
Now that you know have taken the first steps, you can chart your path and map out your journey. In fitness and wellness, we begin with baseline assessments (pre-tests) that will tell you where you are now, and will allow you to monitor your progress as you move toward your goal.
Learning Objectives
At the end of unit, you will be able to:
- Articulate the current physical activity recommendations for optimal health and fitness
- Discuss chronic health problems that are affected by sedentary behaviors and nutrition choices
- Describe the health-related components of fitness and how they differ from each other
- Explain the principles of physical adaptation to training including specificity, progressive overload, reversibility, and individual differences.
- List the steps to maintain safety when designing a well-rounded and effective exercise program
- Explain the four dimensions represented by the acronym FITT Describe the basic anatomy and physiology of the cardiorespiratory system and how it is affected by exercise
- Define energy production and the energy systems Outline the benefits you obtain from cardiorespiratory endurance exercise
- Assess your cardiorespiratory endurance level and set appropriate goals
- Apply the FITT dimensions (frequency, intensity, time [duration], and type) to the development of a cardiorespiratory endurance program
- List basic exercise-related first aid principles and steps to prevent exercise injuries
- Outline the benefits of flexibility exercises
- Identify the factors that influence joint flexibility
- Explain how the different types of stretching exercises work
- Assess your flexibility level and set appropriate goals
- Apply the FITT dimensions to the development of a flexibility program and select safe stretching exercises for major joints
- Describe strategies to prevent and manage low-back pain
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- Lifetime Fitness and Wellness. Provided by : Extended Learning Institute of Northern Virginia Community College. Located at : https://eli.nvcc.edu/ . License : CC BY: Attribution


9.6: Exercise- Transferring the Weights and Assessing the ICs
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Our goal in heavily filtering the data was to improve the ICA decomposition, but as was described in the chapter on filtering, this kind of filtering is usually a bad idea for ERP analyses. So, we’re going to take our optimized ICA decomposition and transfer the weights to the original dataset, which has not been distorted by filtering. To do this, first look at the Datasets menu in EEGLAB and note the dataset number for the dataset containing the ICA weights ( 10_MMN_preprocessed_filt_100Hz_del_ICAweights ). It’s probably #4, but it might be something else if you’ve done some other processing. Now select the original dataset ( 10_MMN_preprocessed ) in the Datasets menu and then select EEGLAB > Edit > Dataset info . In the new window that appears, click the From other dataset button for the ICA weights array , and enter the number for the dataset with the ICA weights (probably 4). Also change the Dataset name to 10_MMN_preprocessed_transferredICAweights , and then click OK . That’s it! You’ve now transferred the weights. You might want to save this dataset to your disk with EEGLAB > Files > Save current dataset as .
You can verify that the weights have been transferred by selecting EEGLAB > Tools > Inspect/label components by map (but first close the window you created with this routine in the previous exercise, if it’s still open). You should see the same maps as in the previous exercise (Screenshot 9.6), because you transferred those weights to the current dataset.
Now let’s compare the time course of the ICs ( EEGLAB > Plot > Component activations (scroll) ) with the time course of the EEG and EOG data ( EEGLAB > Plot > Channel data (scroll) ). You can see that the time course of IC 1 closely matches the time course of the blinks and vertical eye movements in VEOG-bipolar. To the naked eye, there isn’t any obvious difference between IC 1 from this decomposition and IC 1 from our original decomposition (Screenshots 9.2-9.4). However, given that the decomposition as a whole improved, IC 1 from our new decomposition is less likely to be contaminated by activity from other sources (less lumping).
Now let’s see if we can figure out what’s going on with the other ICs and see if any of them should be removed along with IC 1. Let’s start by looking for an IC related to horizontal eye movements. Go back to the plot of the scalp maps (Screenshot 9.6) and see if any of the maps have the distribution you’d expect for horizontal eye movements (i.e., opposite-polarity foci just to the sides of the two eyes). IC 13 looks promising, so click on the 13 above the scalp map for IC 13 (or the IC that has the right scalp distribution if your maps don’t exactly match Screenshot 9.6). A new window will pop up to show the details of this IC. The time course heatmap has a lot of activity at the beginning and end of the dataset, which is what we would expect if large eye movements were most common during the break periods at the beginning and end of the session. (Note that we deleted the break periods in the dataset used for the ICA decomposition, but we’ve now transferred the weights to the original dataset, which still has data during the break periods. The same set of weights is used for every time point, so it’s not a problem to transfer weights to time points that weren’t used in the ICA decomposition.)
Now go back to the scrolling time course plots for the ICs and EEG data and see if the time course of IC 13 matches the time course of the horizontal eye movements in HEOG-bipolar. You might want to display only 6 channels and ICs at a time so that you can see the eye movements better. Screenshot 9.7 shows the EOG data (top) and a few of the ICs (bottom) for the first 10 seconds of the dataset. You can see a beautiful correspondence between IC 14 and HEOG-bipolar. And if you look closely at the other ICs, none of them show the same pattern. ICA has clearly done a good job of isolating the horizontal eye movements with IC 13. We should definitely consider removing IC 13 from the data.
Although none of the other ICs show the same pattern as the HEOG-bipolar channel, IC 3 has a sharp voltage spike at the onset time of each shift in eye position. This is the spike potential shown in Figure 9.1, which is the muscle contraction that causes the eyes to move. Given that the spike potential and the change in HEOG voltage are closely linked, you might wonder why they end up in different ICs. The answer is that ICA tries to find ICs that are maximally independent at a given time point. The HEOG signal is sustained, and the spike potential occurs only at the very beginning of the eye movement, so you often have a large HEOG voltage with no spike potential. And the spike potential slightly precedes the HEOG change, so you can have a large spike potential with HEOG. Consequently, they end up as different ICs. Note that the magnitude of the spike potential in the EEG/EOG recordings varies considerably across participants, so you don’t always see a separate IC for it.
IC 4 has a midline centro-parietal focus and a broad scalp distribution, much like the P3b wave. However, the participants weren’t doing a task in the MMN experiment, so we wouldn’t expect to see the P3b. If you scroll through the component activations and EEG data, it’s hard to see any obvious correspondence between IC 4 and the EEG signals. Moreover, the power spectrum doesn’t reveal a clear peak, so it doesn’t seem to be an oscillation. I really don’t know what IC 4 is.
IC 5, on the other hand, shows a clear peak at 10 Hz (which you can see by clicking on the 5 above the scalp map for IC 5). Also, the scalp map has a strong focus at the occipital pole. Both of those are consistent with the classic alpha-band oscillation first described by Hans Berger in his original EEG study (Berger, 1929). You can see some beautiful alpha bursts in both IC 5 and the posterior EEG electrodes between 57 and 60 seconds.
IC 2 also has a clear peak in its power spectrum, but at approximately 7 Hz instead of 10 Hz. Its scalp map has a focus around Fz. Given this power spectrum and scalp topography, this is probably the commonly-observed midfrontal theta oscillation. You can see bursts of oscillatory activity in this IC at a variety of time points (e.g., 127-128 s, 219 s, 297-302 s, 401-403 s), and you can see corresponding bursts of oscillations in the far frontal channels. However, the oscillation bursts sometimes occur simultaneously in other ICs (e.g., at 127 s), and IC 2 also shows some transient (non-oscillating) activity, so I wouldn’t try to use this IC to isolate midfrontal theta and then use it as a dependent variable.
Check out the rest of the ICs and see if you can figure out what they represent. You’ll see that some contain alpha-band activity, like IC 5, but with somewhat different scalp topographies. This isn’t surprising given that alpha can be observed over different cortical areas at different times. Many ICs have no obvious interpretation. IC 16 has a scalp distribution that is much like IC 1. Blinks often appear in two or even three ICs, so you should take a close look at any IC that has a blink-like scalp map.
If you scroll through the component activations and EEG/EOG data, you’ll see that IC 16 exhibits a high-frequency burst at the beginning of each blink, superimposed on a negative dip. This could be the EMG activity from the muscles that produce the blink. However, the slower negative dip doesn’t seem like EMG, so IC 16 may be mixing EMG and EOG signals. It’s still blink-related, so we’ll consider whether to exclude it in the next exercise.
Blink-related EOG activity is primarily a result of the eyelids sliding across the eyeballs, but there may also be a slight vertical rotation of the eyeballs that produces a voltage. These two effects have similar but slightly different scalp distributions, so they may appear as separate ICs (especially when you have 60 or more channels and therefore 60 or more ICs). In theory, the two eyelids could start and stop moving at slightly different times, which might also produce separate ICs.