Understanding Blocks of Time Use

I discussed student time use with one of my professors several weeks ago. He mentioned the importance of considering how time is allocated across activities in sequence. For some individuals, study-time may be interrupted by other activities, whereas other individuals may avail of contiguous study sessions. This could affect how study time affects academic achievement. Another nuance of study time that was recently mentioned on the blog is the degree of attention exercised during study-time; this also has implications for academic achievement. While the scheduling of study-time could be investigated using the Day Reconstruction Method (DRM), measuring the degree of attention exercised during study is more challenging.

A recent NBER paper (Increasing Marginal Value of Time in Recreation - Raymond B. Palmquist, Daniel J. Phaneuf, V. Kerry Smith) considers the scheduling of time use in "blocks". They focus on leisure time and begin with the premise that leisure activities usually take place in discrete blocks of time that are surrounded by time devoted to other commitments (i.e. non-contiguous scheduling). An economic insight is that it can be costly to transfer time between blocks. They suggest that traditional methods for valuing time using labour markets miss important considerations (due to the costs of transferring between blocks of time).

The Palmquist, Phaneuf, and Smith paper uses non-employment time commitments to infer the shadow value of time spent in recreation. They use a survey that elicited revealed and stated preference data on household time allocation. The results from their work support the hypothesis that there is an increasing marginal value of time for recreation as the block of time increases.

Research Image: Patterns of Emotion Throughout the Day

Below is an image from a study we recently finished in Dublin examining patterns of mood utilising a version of a methodology called the day reconstruction method, a diary approach that was originally developed in a series of papers by Kahneman and colleagues. 6 represents 6am and it goes up until 26 which is 2am. The clear divergence between positive and negative emotions as the day moves on is obvious to see in the graph. Some interesting features such as the spike in tension and anger at about three o'clock are also noticeable so if you are reading this at three o'clock in the afternoon then chill out (or send me a nasty email!).

We will be working on this and related work throughout the next year. Gerard O'Neill in Amarach has worked with us to integrate this work with gis tracking to examine commuting stress and its relation to commute patterns and we will present on this soon. We have also been working on integrating this work with continuous tracking of stress hormones and heart rate.




Some key references:
Kahneman, D., Krueger, A.B., Schkade, D., Schwarz, N., & Stone, A.A. (2004a). Toward national well-being accounts. AEA Papers and Proceedings, 94, 429–34.

Kahneman, D., Krueger, A. B., Schkade, D., Schwarz, N., & Stone, A. A. (2004b).
Day Reconstruction Method. Science -- Full Text. Retrieved on 24 August, 2007 from http://www.sciencemag.org/cgi/content/full/306/5702/1776

Kahneman, D., Krueger, A. B., Schkade, D., Schwarz, N., & Stone, A. A. (2006). Would you be happier if you were richer? Science -- Full Text. Retrieved on 24 August, 2007 from http://www.sciencemag.org/cgi/content/full/312/5782/1908

Recent article by Andrew Steptoe points to neuroendocrine and cardiovascular correlates of daily affect

Steptoe applies a methodology which he perfected studying the positive psychobiological effects of a good cuppa to show that positive emotion, like tea, has many positive effects and can guard against stress. This study uses ecological momentary assessment (EMA) whereby mood is assessed using rating scales at four periods throughout the day. They also use a stress test to evaluate cardiovascular reactivity and then relate this to affect throughout the day. Having a high level of positive affect througout the day means that you have lower levels of systolic BP at rest and after the stress task and also quicker diastolic BP recovery. Interestingly, having low positive affect was predictive of a greater cortisol response and this effect was independent of negative affect. Those who were high in positive affect did not differ from those low on positive affect in terms of negative affect indicating that they are separable concepts rather than existing on a continuum from negative to positive. Positive emotion aslo has independent effects indicated that merely focusing on removing ill-being is not enough.

This article pre-empts what will be quite a significant piece of work when the bloods from this study come back to show relationships between daily mood and a variety of measures of immune function, inflammation, and neuroendocrine function. They did not, however, include cardiovascular measures across the day. Steptoe seems to prefer to examine stress in the laboratory and relate this to daily affect. Coupling both methodologies would be worthwhile. The DRM may offer advantages over EMA and incorporating both into a study and seeing their level of similarity may be worthwhile.

Overall, demonstrating a protective effect of positive emotion on biological stress hormones which is independent of age, BMI, or importantly negative affect is a valuable finding which needs to be replicated in a larger sample.


Neuroendocrine and cardiovascular correlates of
positive affect measured by ecological momentary
assessment and by questionnaire