On the most general level, one can differentiate between four stress concepts: (a) the stimulus concept, (b) the response concept, (c) the transactional concept, and (d) the discrepancy concept. The stimulus concept focuses on situational conditions or events. Within this conceptualization, certain stimuli are stressful—for example, high time pressure, interpersonal conflict at work, or accidents. However, the stimulus concept is problematic because not all individuals react in a uniform manner to the same stressor. Nearly every situational condition or every event may evoke strain in some individuals. Although the stimulus conceptualization leads to conceptual problems, many researchers agree that there are subsets of stimuli that evoke strain in most individuals (Brief & George, 1995; Kahn & Byosiere, 1992).
The reaction concept focuses on physiological reactions as the crucial constituent of stress—that is, stress exists if an individual shows a specific reaction pattern regardless of situational characteristics (Selye, 1956). However, this conceptualization also has its shortcomings. It does not take into account that very different situations can result in the same physiological responses and that an individual's coping efforts may have an effect on that individual's reactions, thus altering the stress response.
Another class of concepts refers both to the situation and to the person when defining stress. The transactional concept brought forward by Lazarus (1966) assumes that stress results from a transaction between the individual and the environment, including the individual's perceptions, expectations, interpretations, and coping responses. In terms of operationalization and measuring stress in empirical studies, this concept has not yet fully developed its potential. Often, proponents of the transactional concept actually rely in their research practice exclusively on verbal responses or physiological measures of strain as indicators of stress. By doing so, they implicitly apply the reaction concept. The discrepancy concept describes stress as an incongruity between an individual's desires and the environment (Edwards, 1992); in operationalizing such a discrepancy, however, researchers face great difficulties.
Thus, stress is a broad term that conveys a variety of meanings. To avoid ambiguity, we refer to stressors and stress reactions or strain throughout this chapter. We use the terms strains and stress reactions synonymously.
Stressors
Stressors are conditions and events that evoke strain (Kahn & Byosiere, 1992). Stressors can be single events such as critical
TABLE 18.1 Overview of Stressors in Organizational Life
Physical stressors Task-related job stressors Role stressors Social stressors
life events or traumatic experiences, and they can also be chronic problems that continue over a longer period of time. The latter often are microstressors, so-called daily hassles (Kanner, Coyne, Schaefer, & Lazarus, 1981)—for example, daily difficulties with finishing one's work in time or daily problems in dealing with difficult clients. ^ Stressors can be grouped into the categories physical stres-Wsors, task-related job stressors, role stressors, social stressors, work-schedule-related stressors, career-related stressors, traumatic events, and stressful change processes (Table 18.1). Physical stressors refer to aversive physical working conditions, including noise, dirt, heat, vibrations, chemical, or toxic substances. They also include poor ergonomic conditions at the workplace and accidents. Physical stressors have psychological effects (Seeber & Iregren, 1992). Task-related job stressors appear while the employee is doing a task; these stressors include high time pressure and work overload, high complexity at work, monotonous work, and disruptions (e.g., caused by an unexpected computer shutdown). Role stressors fall into role ambiguity and role conflict. Social stressors express themselves in poor social interactions with direct supervisors, coworkers, and others. These stressors include interpersonal conflicts at the workplace, (sexual) harassment, and mobbing or bullying (Zapf, Knorz, & Kulla, 1996). Additionally, having to deal with extremely difficult customers can also be conceptualized as social stressor. "ork-schedule-related stressors stem from working time arrangements. The most prominent and well-researched stressors in this category are night and shift work. Additionally, long working hours and overtime belong to this category (Sparks, Cooper, Fried, & Shirom, 1997). Career-Mated stressors include job insecurity and poor career opportunities. Traumatic stressors are single events such as the e*posure t0 disasters, major accidents, or extremely danger-0Usacuvities. Soldiers, police personnel, and firefighters are surned to be particularly prone to the exposure of traumatic ^ssors (Corned, Beaton, Murphy, Johnson, & Pike, 1999). ^national change can also be regarded as a stressor. ■ amples include mergers, downsizing, or the implementa-°1 new technologies. They are stressful because they