“…Example apparent to the naked eye are Figure 6 in Ghirlanda and Ibadullaiev (2015) (where, if not oscillations, at least an overshoot is visible), Figure 3 in Miller, Greco, and Vigorito (1981), and, notably, Figure 2 in Zelikowsky and Fanselow (2010). These are not the only available examples and, in fact, oscillations (not to be confused with the shortest-scale phenomenon of post-peak depression; for a discussion, see Calcagni, Caballero-Garrido and Pellón, 2020) may be more common than currently acknowledged, partly because there are not looked for or are ignored as experimental errors. In turn, they might not be looked for because, to begin with, the existing theories do not predict their occurrence.…”