A criticism of happiness research is that it often relies on what a person says about his or her own happiness. Calling a self-report measure of happiness "subjective well-being" seems not to help much, because the critic then objects "Isn't that subjective?" The answer is that of course self-reports are subjective, meaning that they are from the respondent's own point of view. But the term subjective also drags along connotations of capriciousness and arbitrariness. Never mind that self-report measures of happiness are as reliable and as stable across time as most other measures of psychological characteristics, and certainly more so nowadays than the Dow Jones industrial average or the balance in our retirement portfolios.
Charges of subjectivity - i.e., capriciousness - have been leveled against a great deal of positive psychology research that uses self-report to measure not only happiness but also strengths of character, flow, values, secure attachment, and so on.
We seem to be willing to accept as valid what people say about things that are wrong (including research studies). With exceptions like substance abuse and eating disorders, in which denial can be a part of the problem, the preferred way to measure psychological disorder relies on self-report, through questionnaires or interviews. Why not ascertain things that are right in the same way? Perhaps we accept self-reports about the negative but not the positive because we have a nagging doubt that what is good, including happiness, does not really exist. That is the assumption that positive psychology urges us to reject.
Against this background, a recent study deserves comment. Christopher Oveis and colleagues (2009) published a paper with an imposing title: "Resting Respiratory Sinus Arrhythmia Is Associated with Tonic Positive Emotionality." In plainer English, the title promises the reader evidence that a biological characteristic is linked to well-being, and that promise is kept.
Respiratory sinus arrhythmia (RSA) reflects the neural regulation of the heart's pacemaker via the myelinated fibers of the so-called smart vagus. RSA is assessed by examining the degree of respiration-linked variability in the heart rate. In the study by Oevis and colleagues, The RSA of 80 college students was measured in a laboratory with appropriate electrophysiological devices. One month later and six to eight months later, most of these same students completed self-report surveys measuring such psychological characteristics as extraversion, agreeableness, neuroticism, enduring positive and negative moods, and optimism and pessimism.
Statistically significant correlations were found between the RSA measure and the psychological characteristics reflecting well-being: extraversion, agreeableness, positive moods, and optimism, even six to eight months later. Correlations with the negative psychological characteristics were smaller, especially over time.
The researchers were careful to conclude that RSA is a physiological "marker" of positive emotionality. They did not say that RSA is a better measure of well-being than is self-report or one that should be preferred . After all, RSA scores were validated by checking their agreement with what research participants reported. The obtained correlations were respectably high, but not so high as to imply redundancy between the objective and subjective assessments.
I am not a biological reductionist, and I do not require physiological markers or measures for the sorts of psychological characteristics that I study in order to conclude that they are real. Nonetheless, this study and others like it are important because they blunt the criticism that positive psychology research is merely subjective.
Oveis, C., Cohen, A. B., Gruber, J., Shiota, M., Haidt, J., & Keltner, D. (2009). Resting respiratory sinus arrhythmia is associated with tonic positive emotionality. Emotion, 9, 265-270.