Intraindividual Variability (IIV) And The Visual Steps

In the study of human development it is well accepted that multiple observations are needed to obtain a robust characterization of individuals’ behaviorial tendencies across time and context. The time-scale and frequency of repeated measurement are selected so as to map onto specific change processes. The archives used in Playing The Archive, such as iSAHIB, are examples of just such data sources.

iSAHIB Steps are data visualizations inspired, in part, by research on between-person differences in intraindividual variability (IIV). Each of our Steps is a window into a unique individual’s emotional experiences, how they changed along multiple dimensions and at multiple timescales. Background color bars represent levels of daily well-being – level of self-reported daily emotional health. Lighter colors (bright acqua) indicate relatively higher positive well-being compared to peers, and darker (deep purple) indicate relatively lower well-being. Black bars indicate missing data. Foreground elements represent changes in emotional experience with respect to arousal and valence dimensions, both across and within days. The yellow solid squares indicate the level of reported arousal (sleepy = low, excited = high) for 7+ reports provided each day. The yellow solid lines provide each day’s average level of emotional arousal. Together the lines and symbols provide information about both how the daily average changed from day-to-day and the range of experiences within each day (distances of the day’s squares from the line). Similarly, the pink solid circles and lines provide the same information about day-to-day and within-day changes in emotional valence. Horizontal black lines overlaid on the yellow and pink lines are used to accentuate the changes in daily averages and provide visual continuity.

Beyond their aesthetic value, these Steps visualizations can be used to derive meaning about individuals’ emotional/behavioral tendencies. Looking at the different visual elements we can examine aspects of both within-person change and between-person differences. For example, looking at differences in the backgrounds of three different Steps visualizations one can immediately see the relative differences in extent of change in levels of positive well-being (deep purples to bright acquas). Looking at one person’s Steps allows for examination of the between-day and within-day consistency of emotions (e.g., left-to-right changes in the yellow solid lines and vertical differences in the yellow solid squares). The visualization highlights variability in emotional experience across multiple time-scales (days and situations). For instance, low variability = high consistency within a day is apparent when most of the yellow squares appear relatively close to solid line (1); or consistency across days is apparent with a mostly stable line, with greater variability or range of emotions within-days where the blocks/circles cover a wider area around the line (2); reorganizations are apparent when the lines shift “zones” (3).

Overall, Steps provides abstract representations of the research data that allow viewers to appreciate specific types of variation present in the data, both by looking within a single frame or across the entire set of frames. Beyond their research utility, they become the basis for visual objects displayed on gallery walls, and scores for live music performance.