Friday, September 01, 2006

Causes/Sources of Stress

What is Stress?

There are three main theoretical ways of answering this question and they all have something to say in regards as to what the causes of stress are. Simply put, how we define stress will lead us to certain understandings as to what the causes are.

Stimulus Models of Stress

This approach argues that stress should be understood as a repsonse to certain environmentla stimuli, such as exposure to excessive noise, loss of a job, etc. Holmes and Rahe (1967) were the first researchers to attempt to investigate this model of stress in a seemingly scientific fashion. They began by choosing 43 probably stressful life events, and then asked 400 US adults to rate the relative amount of readjustment that they judged would be required by each of the 43 events. Holmes and Rahe then used their results to construct a social readjustment rating scale (SRRS) that assigns points values to different stressors and which has subsequently been used in research on the relationship between stress and physical illness. Such that if an individual experiences a number of high scoring stressful events in the previous year they are more prone to various forms of illness.

Some researchers felt dissatisfied with the SRRS because many of the events listed in it occur relatively rarely in anyone's life. There was a desire for a scale that reflected to a greater degree the day-to-day variation experienced by people in levels of the stress to which they are exposed. This led Kanner et al. (1981) to devise, using similar techniques to those of Holmes and Rahe, two further scales, a hassles scale consisting of everyday events that cause annoyance or frustration, and an uplifts scale consisting of events that make them feel good. For these researchers it is the everyday stressors that are the primary source of stress rather than significant major life events.

A further development in this line of research has been that we need to understand the nature of the stimulus to gain more insight into the reaction to it. One approach has been to distinguish between qualitatively different types of stressor and a useful fourfold classification has been put forward by Elliot and Eisdorfer (1982):

1 Acute, time-limited stressors: examples could be being threatened in the street or taking the driving test.

2 Stressor sequences: examples could be selling one's house or losing one's job.

Chronic, intermittent stressors: examples could be deadlines for journalists or premenstrual tension.

4 Chronic stressors: examples could be medical emergencies for doctors or living in cramped and overcrowded conditions.

A further distinction, introduced by Spielberger (1966, 1972), can be made between physical threats and ego threats (threats to our sense of self, such as bullying). Spielberger argues that everyone reacts in much the same way to physical threats, while only individuals high in anxiety experience large increases in stress in response to ego-threats.

Other souces of stress within this model are -

Crowding: Unquestionably, density and crowding affect human behavior. Sundstrom (1978), in a review of the literature, revealed that both laboratory and field studies have found density and crowding to be associated with increased aggression, withdrawal from interpersonal relations, increased crime rates, and a number of other negative factors. However because the experience of density and crowding are affected by our perception of the stimulus, this means that not all crowded conditions will create stress. For example, Mitchell (1971) found that, when the factor of poor housing was statistically controlled, high population density in Hong Kong for the most part had little adverse effect. However, when psychological variables were examined, some consistent and significant findings began to emerge. One was that, when nonrelated families occupied the same dwelling unit, stress increased. In other words, the number of people or families living in a house was not so important as the people's perceptions of one another. When people are forced to live with lonrelatives, the conditions are likely to be seen as crowded. Increased stress is the result.

Noise: Because noise is a subjective interpretation of sound, we can expect that not all sound will be percieved as noise. However when sound is interpreted as noise, often when we have no control over the sound, then stress is a common reaction. For example, A study by Glass and Singer (1972) indicated that personal control was an important factor in appraising the stressful effects of noise. Two groups of subjects were exposed to loud, distracting, bothersome noise. Subjects in one group were told that they could control the noise if it was too distracting, but those in the other group were given no such option. A third group was not exposed to noise. All groups worked on a task that required attention and vigilance. The performance of the group exposed to uncontrollable noise was worse than that of the other twc groups. This finding indicates that noise does not necessarily cause performance problems. Rather, the cause seems to be the lack of control that often accompanies loud sounds.

Occupation: The popular impression is that executives suffer from a high level of stress, but research indicates that other occupations are more stressful (Smith, Colligan, Horning, & Hurrel, 1978). Using stress-related illnesses as a criterion, the jobs of construction worker, secretary, laboratory techmcian, waiter or waitress, machine operator, farm worker, and painter are among the most stressful. These jobs all share a high level of demand combined with a low level of control. Another highly stressful job is middle-level manager, such as foreman or supervisor. Middle managers must meet demands from two directions: their bosses and their workers. Thus they have more than their share of stress-related illnesses (Smith et al., 1978). Most executives have jobs in which the demands are high but so is the level of control. The ime is true of physicians, who have jobs that include a very high level of demands but also a high degree of control. Medical students, however, are typically burdened with the undesirable combination of high demands and low control. Vitaliano et al. (1988) found that medical students were subject to high levels of stress and insiderably higher than average levels of anxiety. Furthermore, their anxiety was persistent, with no significant let-up over the nine-month school term.

Response Models of Stress

Because of the endless problems of identifying what stimuli people find stressful another approach has been to understand the response that people have to stress. Thus if we know you are responding to stress we can also then try to identify causes. In a sense the cause of stress is how your body responds to external stimuli.

Research on the physiology of stress originated in the work of Walter Cannon in the first half of the twentieth century. Cannon's theories revolve around the concept of homeostasis, whereby the physiological mechanisms of the body are considered as feedback systems functioning as far as possible to maintain a steady state. Homeostatic balance is disrupted not only by basic bodily needs, as in the case of hunger and thirst, but by any environmental stimulus which disrupts the body's state of equilibrium (e.g. excessive heat or cold, bacterial and virus infections, emotion provoking stimuli), thereby causing a reaction which has the function of reestablishing the inner balance. Anything which disrupts equilibrium may be regarded as a stressor (Cannon, 1932).

Under Cannon's influence, Hans Selye began a programme of animal experimentation into the physiological effects of noxious stimuli and other environmental stressors from the early 1930s until shortly before his death in 1982 (Selye, 1956, 1976). He argued for the existence of a generalized response, known as the general adaptation syndrome (GAS), which occurs whenever the body defends itself against noxious stimuli. The GAS occurs primarily in the pituitary-adrenocortical system and consists of three stages, an alarm reaction in which the body's defences are mobilized, a resistance stage in which the body adapts to the stressor, and an exhaustion stage in which the body's capacity to resist finally breaks down. The GAS may be likened to the process whereby an individual, confronted by sudden unexpected financial demands, takes out a bank loan (alarm reaction), and uses it to meet these demands (resistance stage) until further income is received and the loan repaid (recovery) or bankruptcy results (exhaustion stage). Selye particularly drew attention to the abnormal physiology of the animal during the resistance stage which, if protracted, could lead to what he called the diseases of adaptation. These include ulcers, cardiovascular disease and asthma. Thus anything which creates this kind of response can be viewed as a source of stress.

Interactional Models of Stress

A number of theorists have sought to overcome the problems of stimulus and response models by conceptualizing stress as a relationship between the individual and the environment and developing interactional models. The most influential of these was first put forward by Lazarus (1966). In this model psychological stress is defined as 'a particular relationship between the person and the environment that is appraised by the person as taxing or exceeding his or her resources and endangering his or her well-being'. A distinction is made between primary appraisal whereby an event may be perceived as benign and non-threatening, potentially harmful, threatening to one's self-esteem, or challenging, and secondary appraisal in which an assessment is made of one's ability to cope with the threat or challenge. Stress occurs whenever there is a mismatch between perceived threat and perceived ability to cope. Thus the source of stress is in the interaction between these variables.

Several studies have examined the effect of appraisal on stress and have evaluated the role of the psychological state of the individual on their stress response. In an early study by Speisman et al. (1964), Ps were shown a film depicting an initiation ceremony involving unpleasant genital surgery. The film was shown with three different sounds tracks. In condition one, the trauma condition, the sound track emphasized the pain and the mutilation. In condition two, the denial condition, the sound track showed the participants as being willing and happy. In condition three, the intellectualization condition, the sound track gave an anthropological interpretation of the ceremony. The study therefore manipulated the subjects' appraisal of the situation and evaluated the effect of the type of appraisal on their stress response. The results showed that subjects reported that the trauma condition was most stressful. This indicates that it is not the events themselves that elicit stress, but the individuals' interpretation or appraisal of those events.

Recently, theories of stress have emphasized forms of self-control as important in understanding stress. This is illustrated in theories of self-efficacy, hardiness and feelings of mastery.

1 Self-efficacy. In 1987, Lazarus and Folkman suggested that self-efficacy was a powerful factor for mediating the stress response. Self-efficacy refers to an individual's feeling of confidence that they can perform a refers to an individual's feeling of confidence that they can perform a desired action. For example, the belief 'I am confident that I can succeed in this exam' may result in physiological changes that reduce the stress response. Therefore, a belief in the ability to control one's behaviour may relate to whether or not a potentially stressful event results in a stress response.

2 Hardiness. This shift towards emphasizing self-control is also illustrated by Kobasa's concept of 'hardiness' (Kobasa et al. 1982; Maddi and Kobasa 1984). Hardiness was described as reflecting (a) personal teelings of control, (b) a desire to accept challenges and (c) commitment. It has been argued that the degree of hardiness influences an individual's appraisal of potential stressors and the resulting stress response. Accordingly, a feeling of being in control may contribute to the process of primary appraisal.

3 Mastery. Karasek and Theorell (1990) defined the term 'feelings of mastery', which reflected an individual's control over their stress response. They argued that the degree of mastery may be related to the stress response.

According to these recent developments, stress is conceptualized as a product of the individual's capacity for self-control. Successful coping and nanagement eradicates stress, failed self-regulation results in a stress aonse and stress-related illness is considered a consequence of prolonged failed self-management.


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