One question that has come to the forefront of research on mind-wandering is its relation to happiness. In a high profile article in the journal Science in 2010, Killingsworth and Gilbert published a paper suggesting that periods of mind-wandering where associated with lower levels of happiness using an experience sampling application on an I Phone. Based on these results this paper claimed that “a wandering mind is an unhappy mind”. A prior study I published with collaborators at the University of Aberdeen in the journal Emotion had found that inducing negative mood led to an increase in mind-wandering under laboratory conditions. Together this paints a rather bleak picture of how the self-generated thoughts we experience during mind-wandering contribute to the happiness levels of people in everyday life. One problem, however, with the notion that self-generated thought is associated with unhappiness is that it assumes that all forms of the mind-wandering state are equivalent. Although researchers often discuss the experience as if it was a uniform construct, its high frequency and ubiquitous nature suggests that there may well be different elements to the experience. Along with several different groups of collaborators, I have begun to explore whether the relationship between mind-wandering and unhappiness could be mediated by different types of mental contents.
An early clue that different forms of mental content during mind-wandering could differentially impact mood came from a study we conducted that found that increasing unhappiness led to a retrospective focus to mind wandering. Building on this work we began to wonder whether it was possible to identify the consequences of different mind-wandering states on mood. In a study published in PLOS One led by one of my PhD students – Florence Ruby – we explored whether there are different types of self-generated thoughts and if so whether these have distinct consequences on mood. Using Principle Components Analysis we identified three types of self-generated thoughts – one focused on the future, a second focused on the past and a third associated with the pleasantness of these experiences. Using lag analysis we found that these different forms of experience have different impacts on subsequent mood. We identified that when the content of thoughts are generally positive and related to the past, subsequent mood would tend to be lower. By contrast, if the content of self-generated thought was focused on the future and had negative content then a participant’s subsequent mood was more positive. In short thinking about the past served a disruptive function because it tended to make people less happy, while thinking about the future served a protective function because it ameliorated a negative mood. Together this study shows that self-generated thoughts are not a homogeneous category of experiences, and that different variety of the experience have different consequences on mood.
Other qualities of self-generated thoughts are important in determining it’s link with mood. A study led by post doctoral researcher Michael Franklin at the University of California Santa Barbara and published in a Special Issue on Mind-wandering in the journal Frontiers in Perception, explored how different qualities of mind-wandering such as awareness or interest in the experiences effected mood. We found that in daily life when participants had self-generated thoughts that were interesting they tended to have a more positive mood than when on task.
Together these two studies suggest that self-generated thoughts do not have a uniform consequence on mood. Interesting and future episodes of mind-wandering may lead to a optimistic outlook and hence greater happiness, whereas rumination about the past may perpetuate lower mood. Although these data rule out the basic proposal that a wandering mind is an unhappy mind, as a scientific community we are still a long way from being able to understand why and how these experiences have the complex associations with happiness that we find. One reason why we currently lack a clear account of the complex relationship between self-generated thought and mood is because we lack a formal framework in which to understand the costs and benefits that different types of experiences have on psychological well-being. Such a theoretical account would be invaluable in providing falsifiable hypotheses upon the conditions under which aspects of self-generated thought impact on the human condition in both a positive and negative manner.