Figure 2. Multivariate pattern analysis of phases in the stress cycle.

A Methods. For each subject (S_1…15), responses patterns were created that included the n measures (M) of either established stress markers or thermal imprints of a particular test phase (anticipation, stress, recovery). Response patterns of all but one subject were used to train a classifier to identify physiological response profiles that are characteristic for each of the test phases. This was the basis for the subsequent prediction of the response patterns of the remaining subject as belonging to either anticipation, stress of recovery phase. B Results. Multivariate response patterns of established stress measures obtained for the CPT (MVPA 1, left) reliably predicted the current test phase of a subject well above chance (56% classification accuracy, p<.001). Patterns of thermal facial imprints in the CPT (MVPA 2, right), on the other hand, did not significantly predict the correct phase (40% classification accuracy, p = .13). The histograms display the permutation distribution of classification accuracies achieved by chance (average 33%).