Sunday, October 12, 2014

Does homeostasis explain the stability of life satisfaction in high income countries?

The theory of subjective well-being homeostasis proposes that life satisfaction is controlled by automatic neurological processes in a manner analogous to the maintenance of body temperature. The theory has been proposed by Professor Robert Cummins of the Australian Centre on Quality of Life (ACQOL), Deakin University. The basic idea is that positive and negative experiences can cause temporary changes in life satisfaction, but homeostasis normally brings it back within a set-point range. The exception occurs where chronic failure of the homeostatic system results in depression.

The theory proposes that homeostatic buffers enable humans to function normally:
  • adaptation restores life satisfaction to the set-point range following positive changes in circumstances, such as an increase in income;
  • resilience tends to restore life satisfaction to the set-point range following strong negative challenges.

Resilience depends on external resources, particularly intimate relationships and wealth, and internal buffers designed to minimise the impact of personal failure on positive feelings about the self. The internal buffers can operate at an unconscious level - e.g. assisting an individual to cope by enabling positive emotions to become accessible. They also operate at a conscious level by altering the way individuals see themselves in relation to the challenge (e.g. denying personal responsibility or viewing the failure as unimportant).

The distinguishing feature of the homeostasis theory is not the existence of adaptation and resilience – which are widely acknowledged in the happiness research literature – but the idea that these processes tend to restore emotional systems to unique set-points for each individual.

When I first read about homeostasis theory, a few years ago, evidence that some individuals experience long-term changes in life satisfaction seemed inconsistent with the idea of constant individual set-points. However, as Bob Cummins has pointed out, changes in life satisfaction do not necessarily imply change in an individual’s set-point (or homeostatically protected mood). If initial measurements of life satisfaction are higher than, or lower than, the set-point, then subsequent measurements can be expected to show a return to the set-point range.

My remaining doubts about homeostasis theory centre mainly around the question of how it can be reconciled with the international evidence of lower average life satisfaction in low-income countries. I find it hard to accept that a high proportion of the people in low-income countries who claim to have relatively low levels of satisfaction with their lives are suffering failure of their homeostatic systems. In some low-income countries, e.g. China, relatively low average life satisfaction seems to be accompanied by relatively high positive affect and relatively low negative affect.

Perhaps set-point ranges remain constant – if we think in terms of hypothetical neural correlates – but the relationship between set-point ranges and life satisfaction scales may change with changes in perceptions of what might be possible. As discussed in a recent post, individuals who move from a remote village to a major city might feel that their lives have improved, even though they become less contented with their living standards after moving to the new location. Does that mean they have become more vulnerable to homeostatic breakdown? I am not qualified to make informed predictions in relation to such matters, but my guess is that there would not be an increased risk of breakdown if the people concerned remain optimistic about their prospects in the city and retain the option to return to the village for family support if they need it.

The predictions of homeostasis theory seem to stand up well to tests that have been conducted so far. For example, homeostasis theory predicts that there will be greater variation in subjective well-being among people with low incomes than among people with high incomes. This is because people with low incomes (or low wealth) are more vulnerable to changes in circumstances. Analysis using data from the Australian Unity Wellbeing Index indicates that the standard deviation of subjective well-being is indeed substantially higher for people with relatively incomes, and declines as household incomes rise to around $100,000.

Homeostasis theory seems to provide a more plausible explanation for the stability of average life satisfaction in high-income countries than a rival theory, advanced by some economists, that this stability reflects evaluative judgements of life by the people in those countries. Evidence that life satisfaction is influenced by genes, and strongly related to self-esteem, optimism and feelings of being in control of one’s life, suggests that it is more appropriately interpreted as reflecting the moods (or frames of mind) of respondents than evaluative judgements. 

Researchers who want subjective well-being measures to reflect evaluative judgements that individuals make about the quality of their lives should consider an approach which requires greater cognitive inputs e.g. the ACSA question which asks people to assess their current well-being relative to the best and worst periods of their lives.

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