Could asymmetrical perceptions about the frequency of past and future events explain the Temporal Doppler Effect?

I thank the authors for clarifying how they intend to account for the length of intervening events in their methods. However, by including only a single question about filled rate of duration (for both past and future), I do not see how they can disentangle the potentially separate contributions of length and absolute number of intervening events. I would therefore recommend including two questions for both past and future: one about the length of intervening events (as currently included), and one about the absolute number of intervening events.

The authors have responded very thoroughly and impressively to my first review. The design is now much clearer to me (and in my opinion stronger), and the manuscript is just about ready for Stage 1 IPA.

I have only one further question, related to the revisions that have now been made. For H2-1 and H2-2, the authors propose analysing only a sub-sample of the total sample size based on a power analysis suggesting that N=102 and N=386 would be sufficient, respectively. This power analysis is appears to be based on a generic d (or dz) of 0.4, as advocated by Brysbaert (2019 -- note that this reference is not in the reference list, so I am not sure which article exactly it is referring to; on an additional minor note, please also ensure that you use "dz" for the within-subjects effect sizes and "d" for the between-subjects effect sizes).

Possibly I am missing a key point here, but my main question is: given the generic nature of the 0.4 effect size estimation, why not take advantage of the total sample size in each study to also test H2-1 and H2-2? It is true that H1 requires a much larger sample size than H2-1 and H2-2, but regardless it seems a shame to leave all of that additional data unanalysed when it would be diagnostic about the predictiosn, and when including this extra data will simply have the benefit of making the statistical tests for H2-1 and H2-2 more sensitive to effects smaller than 0.4 (which I assume would still be theoretically relevant). The authors could report an a priori sensitivity power analysis reporting what effect size they have 0.95 to detect for H2-1 and H2-2 given the full sample size (presumably much smaller than 0.4).

My only other comment is that in the study design table, the content of the columns "Rationale for deciding the sensitivity of the test for confirming or disconfirming the hypothesis" and "Interpretation given different outcomes" should be adjusted slightly to fit requirements. The column "Rationale for deciding the sensitivity of the test for confirming or disconfirming the hypothesis" should provide a justification of the smallest effect size of interest and power level for each hypothesis test, rather than a description of what significant differences would indicate (as currently). The existing content for this column should instead be combined with the existing content in the "Interpretation given different outcomes" column and then included solely within the "Interpretation given different outcomes" column.

Minor: in the third column of the study design table there is an inconsistency in line spacing.

The study seems well designed to test the intriguing and plausible alternative hypothesis raised by the authors. The hypotheses and methods - ostensibly the most important aspects of a registered report - are very clear and reasonable. I only have a few queries and comments (point 3 being the most important):

1. The authors identify previous attempts to explain the TDE from perspectives other than spatial movement (Gan et al., 2017; Mrkva et al., 2018; McCormack et al., 2019), but don't describe these alternative explanations in any detail. It would be helpful to further clarify these explanations in order to illuminate the novel contribution of the authors' own hypothesis.

2. The authors write that the past comprises both "predetermined and sudden events", but it would seem that "expected and unexpected events" would be more appropriate in this context.

3. The authors claim that, unlike in previous studies, they will focus on the length of intervening events as well as the absolute number of events. Yet, their Likert scales don't seem to capture event length in any precise manner. How is this factor being incorporated into the current study, and how does this differ from previous studies?

4. It is unclear why the authors would limit their analyses to a small fraction of the sample when testing some of their hypotheses. Why not include the full sample to get a better estimate of the true effect? Perhaps there is a good reason for such a statistical practice, but if so the authors should clarify it.

5. The sample will include residents of Japan, whereas the Caruso et al. (2013) studies seems to have included American undergraduates and M-Turk participants. Are there any potential cross-cultural differences in time perspectives that could produce differences in the findings, independent of the authors' hypothesis? Perhaps this is simply an unavoidable limitation that would need to be addressed in the Discussion.

This is a signed review (Chris Chambers, Cardiff University).

In this Stage 1 submission, Zhang et al propose an interesting pair of experiments to test whether a phenomenon termed the temporal doppler effect (TDE) – in which people perceive events in the past to be further from the present than events at an objectively equivalent point in the future – might be explained by a process related to the filled-duration illusion (FDI) – in which periods of time with a greater frequency of events or changes are perceived as being longer in duration.

Over two experiments, the authors propose to replicate the TDE, and further, to test whether the magnitude of the TDE is related to subjective judgments of event frequency.

My overall evaluation of this proposal is positive: the research question is clearly articulated and the hypothesis offers a potentially elegant test of an underlying cause of the TDE – assuming the TDE itself replicates successfully, which the authors will also test.

My main comments concern the justification of the link between the TDE and FDI, whether the proposed studies provide a sufficiently severe and falsifiable test of the overarching hypothesis, and the degree of methodological detail. I summarise these points below and have attached a commented version of the Stage 1 manuscript which expands these points and places them in a specific context (along with some additional suggested revisions).

1. The authors’ hypothesis that the TDE is related to (and possibly driven by) same/similar mechanisms to the FDI depends on an auxiliary assumption (tested in H2-1) that people will report a greater frequency of events in the past than they will anticipate in the future. I may have missed this, but I couldn’t find any basis for this hypothesis, either based on theory or previous evidence. As noted in my in-line comments in the manuscript, I feel this issue needs more attention and foundation.

2. It wasn't clear to me whether H2-2 (event frequency related to psychological distance) will be tested through separate correlations in past and future conditions, or through the data collapsed across these conditions. This in turn led me to wonder whether the link between the TDE and event frequency is being tested in the most severe way possible given the current between-subjects design in which past and future judgments are made by separate groups. As noted in my in-line comments, an augmented design could involve the inclusion of past and future judgments in the same participants (in a counterbalanced order) – this would allow for the calculation of a Past vs Future difference score which could then be related to the polarity and magnitude of the TDE. In addition, by selectively analysing the first session of the counterbalanced sequence, the authors could test H1 in a comparable between-subjects manner to Caruso 2013; and by taking into account the difference in event frequency between Past vs Future, the authors could establish a tighter link between the measures. For example, would participants who show a robust opposite trend in event frequency between Past vs Future also show an opposite TDE? If so, this would provide strong support for the authors' overarching proposition. If not, it seems to be it would also provide a more severe and convincing disconfirmation.

3. Throughout the manuscript, there are various points where greater methodological detail needs to be provided, e.g. concerning sampling, exclusion criteria, and instructions to participants. I was also left wondering whether the survey question should include attention checks to protect against inattentive or random responses. Finally, I felt that the rationale for both the 1-month and 1-year studies needs strengthening, over and above the fact that the studies replicate the approach taken by Caruso 2013.

The attached in-line comments include expanded discussion of the above points and some additional minor points, including some suggested language edits.