Wired for Love: Studying Physiological Reactivity in Married Couples

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By Keith W. Harris

University of California, San Francisco

Few researchers employ physiological measures in their studies of marital interaction. The scarcity of physiology studies in the marital literature is more likely due to lack of training and resources than to lack of interest. More importantly, it seems possible that couples researchers have underestimated the contributions that physiological measures can make to their overall understanding of marital functioning. The goal of this article is to familiarize members of the Couples SIG with the marriage and physiology literature and to perhaps inspire some to broaden their studies of couples to include measurement at the physiological level.

Why Study Physiology in Married Couples?

Physiological data can be a valuable complement to customary measures of marital interaction. Take for instance a study of positive and negative affect in marital conflict. A typical approach might include self-report (e.g., pre- and post-interaction ratings of affect) and observational data (e.g., behavioral coding of the interaction). Consider an interaction that is mostly positive except for a brief highly negative exchange in the middle. Whereas pre/post ratings of affect would not capture the variability in this case, continuous physiological data would likely reveal a spike in arousal during and after the negative exchange. Though observational coding could capture the behavioral variability in this example, it too could be informed by physiological data. Couples often behave atypically in the laboratory (Foster, Caplan, & Howe, 1997), and a calm demeanor may belie significant internal emotion and arousal. An interaction that appears positive on the surface could be the product of two angry people on their best behavior. Physiological measurement would offer a window into the putative internal turmoil such an interaction might generate. Since most physiological measures are not under conscious control, physiological data offer a means of circumventing the self-presentation bias that is endemic to observational studies of marital interaction.

Selected Findings from the Marital Interaction and Physiology Literature

Marriage provides a perfect venue for the study of physiology: happy marriages buffer each spouse from stress and are health promoting (House, et al., 1988), while unhappy marriages not only fail to buffer spouses from stress, but also contribute to stress via increased conflict (Kiecolt-Glaser, et al., 1993). John Gottman and his colleagues were the first to study marital interaction and physiology systematically, and in the past twenty years they have gathered a wealth of data on the role of physiological arousal in marital dissolution. The other leader in this field, Janice Kiecolt-Glaser, has accumulated compelling data on the effects of marital conflict on immune and endocrine functioning. The following sections outline the important findings from these pioneers? laboratories and offer suggestions for future inquiries.

Marital conflict is physiologically arousing.

To the extent that conflict is characterized by negative behavior, it is physiologically arousing. Similarly, distressed couples typically exhibit greater reactivity in laboratory interactions than nondistressed couples because they engage in more negative and less positive behavior. It should be noted, however, that even happily married newlywed couples exhibit elevated stress hormones after conflict (Kiecolt-Glaser et al., 1996).

Physiological arousal impacts the marriage.

Gottman and colleagues? (e.g., 1996) work suggests that diffuse physiological arousal (DPA; i.e., a high arousal state) during conflict is predictive of divorce. DPA is problematic for couples because it limits constructive behavior and often leads to behavioral escalations. Additionally, the discomfort of DPA can lead participants to withdraw or avoid conflicts entirely, leading to greater problems in the future.

Physiological arousal impacts health.

Low marital quality is associated with greater likelihood of illness and symptom exacerbation. The link between marital quality and health is thought to be physiological arousal during marital conflict. In support of this, Kiecolt-Glaser and colleagues have shown that marital conflict is associated with elevated stress hormones and down-regulation of the immune system (e.g., Kiecolt-Glaser et al., 1993). In essence, marital conflict operates as a chronic stressor, weakening the immune system's ability to prevent illness.

There may be gender differences in physiological arousal.

The evidence on gender differences in physiological reactivity is decidedly mixed, with studies concluding that husbands are more reactive, wives are more reactive, or that no differences exist (cf., Gottman & Levenson, 1988; Kiecolt-Glaser, 1996). At the risk of oversimplification, Gottman suggests that husbands are more reactive and that this explains husband withdrawal behavior (i.e., it is a means of physiological soothing). Kiecolt-Glaser, on the other hand, suggests that wives are more reactive and that this explains the finding that wives exhibit poorer health than husbands in distressed marriages. Because their studies differ in methods and populations, a direct comparison of Gottman and Kiecolt-Glaser?s gender findings is beyond the scope of this article.

Certain traits and behaviors have a stronger association with physiological arousal than others.

Traits such as dominance and hostility are associated with elevated cardiovascular reactivity in marital interaction (e.g., Smith & Brown, 1991). Negative behaviors such as Gottman?s four horsemen of the apocalypse (criticism, defensiveness, withdrawal and contempt) are also associated with increases in physiological arousal. Regarding positive behaviors, numerous studies have concluded that they are not related to physiological functioning, while recent evidence suggests that positive behavior may be related to lower stress hormones and lower heart rate during conflict (See Kiecolt-Glaser & Newton, 2001 for review). It is my contention that marital conflict is the wrong domain in which to examine the effects of positive behavior on physiological arousal. A more fruitful domain might be social support (see discussion of my dissertation, below).

Suggestions for Future Inquiries

The marriage and physiology literature has focused primarily on harmful interactions between spouses and the long-term damage these interactions can cause. While it is important to understand the harm spouses can inflict on one another, it is equally pressing to understand the ways spouses help each other. In fact, one of the most obvious conclusions to be drawn from the marriage and physiology literature is that couples therapy ought to include techniques for soothing the physiological reactivity that accompanies stressful interactions. Social support is a potentially valuable domain for understanding the way marriage buffers spouses from the effects of stress. In my doctoral dissertation I measured physiological arousal during social support interactions and found that support (i.e., positive behavior) from a spouse was associated with lower heart rate and blood pressure. This was true only for wives, however. For many husbands, the social support interaction took the form of a confessional, which can be highly physiologically arousing even in the presence of a supportive spouse. Further research is needed to understand the ways that spouses can physiologically soothe one another.

Beyond the physiological indicators of stress (e.g., blood pressure, heart rate, cortisol), couples researchers are beginning to study the physiological concomitants of gender (e.g., testosterone), bonding (e.g., oxytocin), and positive affect (e.g., electrical activity in the muscles responsible for smiling), to name but a few. Below are two additional intriguing but unanswered questions regarding marital interaction and psychophysiology.

Is love a chemical addiction?

Everyone is familiar with the honeymoon period in a relationship, where everything is exciting and fresh. Panksepp and colleagues? work with animal models suggests that elevated levels of endogenous opioids may cause this sense of euphoria. As with any addiction, the new lover seeks repeated contact with the object of his/her affections in order to regain the "high." Forced separation creates psychological and physiological withdrawal, complete with separation distress that can mimic depression (Panksepp, 1998). Though much of the work on opioids has been conducted on animals, the possibilities for couples research are exciting.

Is there a neurological substrate for marital satisfaction and marital stability?

Neuroscience may hold unique promise in the study of marital interaction. Davidson and colleagues have reported that positive emotions are associated with greater activation of the left frontal region, and negative emotions with greater activation of the right frontal region of the brain. What might we learn from EEG or ERPs collected while couples observed a videotape of their interaction? Might satisfied couples exhibit greater left frontal activation? Might this asymmetry be predictive of marital stability or therapeutic outcomes? Because asymmetrical left activation occurs in approach-related emotions and right activation in withdrawal-related emotions (Davidson, 1992), at the behavioral level might we even see neurological concomitants of demand-withdraw behavior?

Conclusion

Though researchers have been studying physiology in marital interaction for over twenty years, the field is young and many unanswered questions remain. Skilled behavioral researchers such as those in the Couples SIG would be welcome additions to the field. For those whose curiosity has been piqued, below are recommendations for further reading and a cost estimate for setting up a laboratory to measure autonomic responses during marital interaction [not reproduced here]. Autonomic responses that could be measured in the lab without great expense or blood draws described below include cardiovascular activity (e.g., heart rate, cardiac output, vagal tone, blood pressure, total peripheral resistance) and electrodermal activity such as skin conductance level.

Recommended Reading

Cacioppo, J. T. & Tassinary, L. G. (1995). Principles of Psychophysiology: Physical, Social, and Inferential Elements. New York, NY: Cambridge University Press.
This edited book holds a wealth of information on psychophysiology. It is organized into sections on conceptual foundations, biological foundations, general concepts, systemic psychophysiology, and statistical analysis of psychophysiological data.

Kiecolt-Glaser, J. K. & Newton, T. L. (2001). Marriage and health: His and hers. Psychological Bulletin, 127(4), 472-503.
The definitive current review of marriage and physiology studies. As the title suggests, the review is organized around the positive and negative impact of marriage on health, with special emphasis on possible gender differences.

References

Davidson, R. J. (1992). Emotion and affective style: Hemispheric substrates. Psychological Science, 3, 39-43.

Gottman, J. M. & Levenson, R. W. (1988). The social psychophysiology of marriage. In P. Noller and M. A. Fitzpatrick (Eds.), Perspectives on marital interaction (pp. 182-199). Clevedon, England: Multilingual Matters.

Gottman, J., Coan, J., Carrere, S., & Swanson, C. (1998). Predicting marital happiness and stability from newlywed interactions. Journal of Marriage and the Family, 60, 5-22.

House, J. S., Landis, K. R., & Umberson, D. (1988). Social relationships and health. Science, 241(4865), 540-545.

Kiecolt-Glaser, J. K., Malarkey, W. B., Chee, M., Newton, T., Cacioppo, J. T., Mao, H., & Glaser, R. (1993). Negative behavior during marital conflict is associated with immunological down-regulation. Psychosomatic Medicine, 55, 395-409.

Kiecolt-Glaser, J. K. & Newton, T. L. (2001). Marriage and health: His and hers. Psychological Bulletin, 127(4), 472-503

Kiecolt-Glaser, J., Newton, T., Cacioppo, J., MacCallum, R., Glaser, R., & Malarkey, W. (1996). Marital conflict and endocrine function: Are men really more affected than women? Journal of Consulting and Clinical Psychology, 64, 324-332.

Panksepp, J. (1998). Affective Neuroscience. London: Oxford University Press.

Smith, T. W. & Brown, P. C. (1991). Cynical hostility, attempts to exert social control, and cardiovascular reactivity in married couples. Journal of Behavioral Medicine, 14, 581-592.