International Encyclopedia of Systems and Cybernetics

1.An internal tension induced in a system by unfavorable external factors, impacts of situations.

Materials can be stressed, for example by excessive weight, compression, pulling or stretching. The result is strain, and sometimes breakdown.

The concept has been extended to physiology (see hereafter), and in a somewhat metaphoric way, to psychology and social psychology.

2. The state corresponding to all non-specific responses of the body to any demand.

(This definition is a synthesis of various more or less equivalent ones given by H. SELYE, who introduced the concept) (1975).

"Any demand" is practically anything that affects the system's homeostasis, which means quite normal activities as well as aggressions coming either from the environment or from the invironment.

SELYE states some interesting points:

"- The stress response is, by definition, not specific, since it can be produced by virtually any agent.

"- The stress is not a non-specific reaction: The pattern of the stress reaction… affects certain organs in a highly selective manner.

"- Stress is not necessarily something bad:… The stress of exhilarating, creative, successful work is beneficial, while that of failure, humiliation, infection is detrimental.

"- Stress cannot and should not be avoided" (Ibid, p.63)

The concept of stress is closely related to the General adaptation syndrome concept, also introduced by SELYE.

While it is originally biological, it could quite probably be usefully generalized to psychology (HORVATH, 1959), to the social sciences (M. Mc LUHAN) and to any type of systems in general.

According to M. TIMSIT-BERTHIER (see Ph. LAMBERT, 1998), the mental component of stress – which probably never appears in animals, because their behavior is mainly organized at the limbic level of their brain – becomes very important and probably dominant in the human species.

"Stress traduces any semantic or psychological reaction of an individual who feels that what is demanded from him exceeds his/her possibilities of response" (p.331)

It is of course difficult in most cases to differentiate both aspects: "Is the marathon runner becoming physically stressed when the rhythm of the race becomes unsustainable for him, or mentally when he is not anymore able to maintain himself on par with his competitors?"

In practical contemporary life, negative future expectations – whether imaginary or more or less founded (fear of losing one's job for ex.)

- which are mental and psychological, seem to make psychological stress as the initial stage of the process, which becomes basically psychosomatic.

This seems closely connected with the development of time perception in man. "It is now known that it is not so much the intensity of the hormonal secretions than their disorganization in the temporal dimension that leads to pathological effects" (p.339)

G. BATESON made the curious comment that "… stress is a lack of entropy, a condition arising when the external environment or internal sickness makes excessive or contradictory demands on an organism's ability to adjust (1979, p.230).

Would this not be better expressed as "a lack of capacity to produce entropy". BATESON himself adds indeed: "The organism lacks and needs flexibility having used up its available commitments alternatives" (Ibid).