Modeling the Diffusion of Psychological Stress

Introduction

Growing interest has surrounded the roles of cognitive appraisal and emotions in physiological responses to psychological stress (Tomaka et al., 1993; Feldman et al., 1999; Feldman et al., 2004; Thayer et al., 2012; Kelsey et al., 2012; Gordon et al., 2012; Kemp et al., 2013). According to Cohen, Janicki-Deverts, & Miller (Cohen et al., 2007), psychological stress occurs when an individual perceives that the environmental demands exceed his or her adaptive ability to meet them. This gap gives rise to the label of oneself as stressed and elicits a concomitant negative emotional response.

The previous definition of stress integrates and extends the following classical approaches to stress:

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  Response-based model (Selye, 1974): “Stress is the nonspecific response of the body to any demand made upon it.”

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  Stimulus-based model (Holmes & Rahe, 1967): Stress involves “…events whose advent… requires a significant change in the ongoing life pattern of the individual.”

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  Transactional model (Lazarus & Cohen, 1977): Stress involves the “judgment that environmental or internal demands tax or exceed the individual’s resources for managing them.”

From a systemic point of view, stress can be seen as a dynamic process that affects many individuals, but not all, and which is transmissible through a “relationship.” (Diederich, 1997; Haslam et al., 2005; Nunn & Altizer, 2006; Ong et al., 2006; Rudmin, 2003; Fiske, 2013). Although it is often simple to determine how stress is trans-mitted between lovers, relatives, and close friends, it is more difficult to determine the causes of stress diffusion among people in other kinds of categories. For example, it can be quite difficult to predict stress transmission be-tween two classmates who just say hello to each other once or twice a week. Likewise, it would be difficult to fore-see stress transmission between people and other people whom they encounter in daily activities but whom they really do not know.

Recent research on complex systems, statistical physics, network analysis, and other disciplines has given us the opportunity to explore the diffusion process in complex phenomena, such as stress (Wrzus et al., 2013).

However, to study stress diffusion among individuals, we must develop complex mathematical models of psy-chological systems. To accomplish this challenge we must start by assessing the dynamics of stress caused by and experienced by an individual. Thus, we will consider two interconnected individuals, define the stress transmission, and, eventually, extend the analysis to many networked individuals and to stress diffusion through complex net-works. (See Figure 1.)

Figure 1.

Stress diffusion: Input-output system, interconnected and networked individuals

Psychological Stress: Does It Affect Or Infect?

Psychological stress can be analyzed as a dynamical systems in which a state can have an input variable that changes the original state, and an output variable that changes others' states.

Two different subject-focused perspectives approach stress from a dynamical point of view:

• 1.

  Stress Affects: How stress is contracted from others (input)

• 2.

  Stress Infects: How stress is infected to others (output)