Research Perspective Volume 16, Issue 17 pp 12108—12122

Figure 9. Mean function and eigenfunctions for longitudinal behavioral data. The estimated mean function μ^ and the first three estimated spherical eigenfunctions ϕ^1, ϕ^2, ϕ^3 for the behavioral fly data using spherical functional principal component analysis. The first three eigenfunctions explain 96.54% of the total variation, with the individual components explaining 80.55%, 12.23% and 3.76%, respectively.