AWA: Academic Writing at Auckland

Stress is often defined as the discrepancy between psychological and physical demands of the environment and the resources that one has to cope with such demands (Sarafino, Caltabiano, & Byrne, 2008). This essay will evaluate the advantages and disadvantages of using human laboratory experiments, animal experiments, and surveys to test stress-related health psychology theories. The main argument is that no approach is superior, as all approaches are useful for testing different stress-related theories.

Human laboratory experiments are a research method conducted on humans in a laboratory that involves manipulating an independent variable to influence a dependent variable (Sarafino et al., 2008). An advantage is that they control as many confounding variables as possible, which is important for testing stress-related health psychology theories because it isolates the experiment to the variables that the theory is interested in and allows possible causal relationships to be identified (Sarafino et al., 2008). In a study which tested the theory that imagined social support reduces cardiovascular reactivity to a speech stressor, confounding variables were controlled by randomly allocating participants to experimental conditions, thinking about a supportive tie versus a casual acquaintance, and exposing participants to the same the procedures, such as the information they were told, baseline measures, etc (Smith, Ruiz, & Uchino, 2004). Effectively, controlling for confounders increased the certainty of the causal relationship between cardiovascular activity and support representations.

However, since humans have complex genetic, psychological, and environmental backgrounds, it is difficult to control all confounding variables. Although many confounders were controlled in Smith et al. (2004), some still remained. For example, changes in cardiovascular activity could have been produced by mood induction rather than support representations. Therefore, human laboratory experiments increase certainty of causal relationships, but cannot prove them.

Another disadvantage of human laboratory experiments is that the experimental environment may be artificial. In Smith et al. (2004), participants performed a speech to a taped debater. Contrastingly, speeches in real life are often performed to a live audience, which has bigger implications (eg. increased embarrassment) on the subject. Consequently, imagined social support may not have much effect on cardiovascular reactivity to speech stressors in real life, as the stress may be greater. Therefore, the artificial nature of human laboratory experiments mean they may be unable to test whether stress-related health psychology theories apply in real life (Falk & Heckman, 2009).

Another disadvantage is that they are not always ethical or practical. For example, Selye’s General Adaptation Syndrome, which theorises bodily reactions and health consequences of long-term stress, cannot be tested with human laboratory experiments as it is unethical to induce chronic stress on humans (Cohen, Line, Manuck, Rabin, Heise, & Kaplan, 1997). When human laboratory experiments are not possible, animal experiments may be conducted. This was the case for Cohen and colleagues (1997), who experimentally tested the theory that chronic stress increases illness risk on monkeys. Therefore, an advantage of animal experiments is that they can test stress-related health psychology theories that cannot be tested on humans, as it is easier to get ethics approval for animals (Sarafino et al., 2008).

Similar to human laboratory experiments, animal experiments can also study cause-and-effect relationships. However, as it is easier to control animal environments, animal experiments exert more control over confounding factors. In Cohen et al. (1997), confounding factors such as calorie intake was controlled by feeding all monkeys about 150 calories of food per kilogram of body weight each day, which would be impossible to do on humans. Therefore, the increased control means animal experiments can more effectively test causal relationships among stress-related health psychology theories.

However, a disadvantage of animal experiments is that the findings may not generalise to humans. Although Cohen et al. (1997) used macaque monkeys because they are morphologically, physiologically, and behaviourally similar to humans, they are also different. For example, humans have more complex cognitive process (Stanford, Allen, & Anton, 2009). Consequently, the idea that social stress may have different meanings for monkeys and humans may explain why the results (no association between chronic social stress and immune functioning) from Cohen et al. (1997) contradicted human correlational studies (O’Leary, 1990). Therefore, stress-related health psychology theories tested with animal experiments may not apply to humans.

Another disadvantage is that they cannot test certain stress-related health psychology theories, such as the theory that perceived stress influences immune functioning. This is because it is near impossible to measure animal perception (Sarafino et al., 2008). Therefore, animal experiments may be limited to testing health psychology theories that involve observable factors, such as physiological reactions to stress depicted in Canon’s flight or fight model.

Surveys are a pen-to-paper measurement tool that gathers information through a question and answer format (Sarafino et al., 2008). One advantage is that it can measure many variables and look for associations. However, a major advantage is that it can measure psychological variables, which is important for testing stress-related health psychology theories that involve psychological factors, such as the theory that perceived stress affects health outcomes. This theory was tested by Cohen and colleagues (1993), who used a survey to measure psychological stress by asking respondents to describe their perceived stressful life events and the extent to which they perceived current demands exceeding their coping abilities (Cohen, Tyrrell, & Smith, 1993).

However, surveys may not always measure the variable of interest in a particular health psychology theory accurately. For example, the Social Readjustment Rating Scale uses life-changing events to measure stress levels. However, some of the items do not adequately measure stress. For example, the item referring to changes in finance does not specify whether such changes are an increase or decrease, in which the latter would be more stressful (Sarafino et al. 2008). Furthermore, surveys are often subject to biases such as memory recall, non-response, etc (Sarafino et al. 2008). Any of these issues can impair the survey’s ability to measure stress accurately, and therefore the ability to test stress-related health psychology theories accurately.

Overall, human laboratory experiments, animal experiments, and surveys all have advantages and disadvantages depending on the type of stress-related health psychology theory being tested. Surveys are good for testing stress-related theories that involve psychological factors, which animal studies are not. However, human and animal laboratory experiments and are good for testing causality among stress-related theories, which surveys are not. Therefore, no approach is superior, as the approaches can complement one another when one approach falls short in a particular area. Treating the approaches as complements will enhance the way we test stress-related health psychology theories.

References

Cohen, S., Line, S., Manuck, S. B., Rabin, B. S., Heise, E. R., & Kaplan, J. R. (1997). Chronic social stress, social status, and susceptibility to upper respiratory infections in nonhuman primates. Psychosomatic Medicine, 59(3), 213.

Cohen, S., Tyrrell, D. A. J., & Smith, A. P. (1993). Negative life events, perceived stress, negative affect, and susceptibility to the common cold. Journal of Personality and Social Psychology, 64, 131-131.

Falk, A., & Heckman, J. J. (2009). Lab experiments are a major source of knowledge in the social sciences. Science, 326(5952), 535.

O'Leary, A. (1990). Stress, emotion, and human immune function. Psychological Bulletin, 108(3), 363.

Sarafino, E.P., Caltabiano, M.L., & Byrne, D.G. (2008). Health psychology: Biopsychosocial interactions, 2^nd Australasian ed. Milton, QLD.: John Wiley & Sons Australia.

Smith, T. W., Ruiz, J. M., & Uchino, B. N. (2004). Mental activation of supportive ties, hostility, and cardiovascular reactivity to laboratory stress in young men and women. Health Psychology, 23(5), 476-485.

Stanford, C., Allen, J. S., & Antón, S. C. (2009). Biological Anthropology, 2^nd ed. New Jersey: Pearson Prentice Hall.