Secondary Analysis of a Brief Parent-Implemented NDBI on Activity-Engaged Triadic Interactions Within Mother–Child Dyads

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study is an intriguing investigation that secondarily analyzed whether an intervention using video feedback to promote parent-child communication among infants of various developmental types and their mothers not only achieved its primary goal of enhancing communication but also fostered the development of triadic interactions. 
This finding suggests that more meticulous intervention strategies are needed for the targeted behaviors, which is an important implication for clinical practice.

However, when observing secondary effects on outcomes not initially targeted, the importance described in Section 4-3 cannot be said to be emphasized. Particularly, given that the observed cases of autism involved significant difficulties with joint attention and interaction, the limitations of this intervention method should have been foreseeable beforehand.

It was concluded that no significant changes were observed in the participants' triadic interactions during the intervention period. However, employing different coding methods may reveal clearer indications of secondary effects. As the authors themselves state, I recommend analyzing the interactions at a more granular level.

The following are additional minor points for confirmation.

The notation “interobserver agreement (IOA)” must be displayed upon initial presentation.

Were the ethical procedures for this study the same as those agreed to by participants in the original research? Or were they newly implemented for the secondary analysis?

The following is simply a question.

After 10 minutes of parent-child play, there is a feedback time. How do the children spend this time? Their words and actions during this period are also interesting (such as whether they make appeals for attention from their parents).

Author Response

Please see the attached word doc for specific responses. Than you for your service with reviewing our revised manuscript!

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors,

First of all, I would like to congratulate you on your work. The topic addressed is highly interesting and relevant, and your results are promising. The potential applications in ecological settings and the possibilities for generalization within the family environment are particularly noteworthy. I also believe that the study offers clear advantages in terms of continuity and early intervention. The opportunities afforded by video recording for work in rural or remote areas are especially valuable.

In this regard, I would like to know precisely how the coding was conducted. Methodologically, the codes are very well explained; however, I am left wondering whether the coding was carried out manually or with the support of any software, and whether it was performed by a single person or if triangulation was implemented. I believe that including this information in the methodology—which is otherwise very clear and transparent—would strengthen that section.

Regarding the sample, I assume that the names used are fictitious for data protection purposes, and this should be explicitly stated. Additionally, only mothers participated in the study, and the play activities differed for each child. These aspects should be considered in the study’s limitations as well as in future research directions. There is also a gender imbalance among the participants which, although inevitable with a sample size of three, is relevant given recent studies indicating that girls may present different manifestations of ASD. This should be taken into account when analyzing the potential for generalization. I want to emphasize that these are not criticisms but suggestions aimed at clearly outlining the sample limitations and identifying future lines of research.

Finally, I would like to highlight the clarity with which the results are presented. Both the graphs and the tables provide very useful visual support. In this respect, I suggest the possibility of including the developmental trajectories of the three children in a single graph to facilitate more direct visual comparison.

Once again, I extend my congratulations. I hope these suggestions help improve the final manuscript and contribute to highlighting the value of your research work.

Best regards,

Author Response

Please see the attached word doc for specific responses. Than you for your service with reviewing our revised manuscript!

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript offers a transparent, scientifically honest contribution to the literature on naturalistic developmental-behavioral interventions. One of the most commendable aspects of this work is the authors’ willingness to publish null results. In a field often plagued by publication bias favoring only significant findings, the report that a brief, parent-implemented intervention did not yield immediate changes in complex triadic interactions is valuable. It provides a necessary boundary condition for what practitioners can expect from short-term telepractice coaching. I also appreciated the theoretical pivot the authors utilized – by framing the lack of functional relation not as a failure of intervention, but rather as an illustration of the developmental hierarchy, where foundational skills like joint attention must solidify before complex skills like activity-engaged triadic interactions emerge, the authors proffer a meaningful interpretation for researchers.

While there is much to like about this manuscript, there are several concerns that I have:

 - The authors explicitly note in their limitations that their coding scheme failed to separate joint engagement from triadic interactions, effectively lumping two distinct developmental stages into one complex variable. Since this is a secondary analysis of existing video data, it is unclear why the researchers did not take the opportunity to recode the data to isolate these sub-skills.

- If the theoretical argument is that foundational skills precede complex ones, the manuscript would be significantly stronger if the data analysis actually tested this. For instance, did joint engagement (without the triadic communicative exchange) increase even if the full triadic interaction did not? By not uncoupling these variables, the study potentially masks subtle progress that would validate the authors’ hypothesis about skill trajectory.

- The manuscript describes the intervention as focusing on five specific NDBI strategies (e.g., model language, arrange environment) intended to increase frequency of child communication. However, the theoretical bridge explaining why these specific strategies, delivered over a brief 4-6 week period, should result in the complex coordination of attention required for activity-engaged triadic interaction is weak.

- The authors rely on the assumption of a collateral effect, but without a component in the intervention that explicitly scaffolds the “checking in” or “gaze shifting” required for triadic interaction, the hypothesis feels somewhat optimistic. A stronger theoretical framework is needed to justify why an intervention designed for foundational communication frequency was expected to move the needle on such a high-level skill in the first place.

- The narrative interpretation of the visual data in the results section feels a bit generous regarding the “upward trends” for the participants Cece and Ron. The text suggests that Cece showed a maintenance of levels with a very slight increase, and Ron showed a slight increase in level and trend toward the end. However, as seen in Figure 1, the data for both participants are highly variable and largely overlap baseline levels. Ron’s data, in particular, shows a significant dip at session 18 (dropping to nearly 5%) before recovering. While the authors are careful to state that no functional relation was established, the language regarding these trends implies a level of optimism that the visual data may not fully support. I would recommend adopting more conservative language that aligns strictly with the flat effect size reported (0.061).

- The instability of the baseline data for the first participant, Johnny, poses a threat to internal validity. As the authors note, Johnny displayed variable baseline levels, ranging from nearly 40% to roughly 10%, and then spiked back up to over 50% immediately before the intervention. This high variability and the potential outlier nature of the final baseline point make it difficult to attribute the subsequent intervention data (hovering between 10% and 40%) to the independent variable or simply to natural fluctuation. While the authors acknowledge the variability, this limitation complicates the ability to draw any firm conclusions about the intervention’s efficacy for this dyad, even in the face of a null result.

- The use of 10-second partial interval recording raises questions about measurement sensitivity for such a complex, reciprocal behavior. Triadic interactions can be fleeting. Partial interval recording often overestimates the duration of behavior but can sometimes mask the frequency of discrete exchanges if they occur multiple times within an interval or span across the break of an interval. The manuscript would benefit from a brief justification of why partial interval recording was selected over frequency count or momentary time sampling for this specific type of complex social exchange.

- While single-case designs do not aim for population-level generalizability, the description of the participants is quite brief. For example, the description of Johnny notes that he played with figurines, and Cece played with music and books. Given that the dependent variable is activity-engaged interaction, more detail on the child’s pre-intervention play skills (functional vs. symbolic) would help the reader understand if the children were developmentally ready for triadic interactions. If a child does not yet demonstrate functional play with objects, expecting activity-engaged triadic interaction might be premature regardless of the intervention intensity.

Author Response

Please see the attached word doc for specific responses. Than you for your service with reviewing our revised manuscript!

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for the detailed response and the revisions made to the manuscript. The effort to address the previous feedback is evident, and the transparency regarding the study's challenges contributes to the paper’s integrity. While the textual revisions are comprehensive, one significant methodological limitation remains:

From a rigorous methodological standpoint, lack of time is a logistical excuse, not a scientific justification. Where necessary, the authors can request an extension form the editorial team. Moreover, although the transparency mitigates the risk of misleading readers, the decision not to recode the data to uncouple joint engagement from full triadic interactions leaves the theoretical “foundational skills" hypothesis untested. The study relies on the assumption that these skills may have improved in the absence of triadic interactions, rather than empirical data.

Conducting this recoding would transform the theoretical discussion into a data-supported conclusion. If this remains unaddressed, ensure that the discussion section explicitly frames the foundational skills argument as a theoretical implication derived from the null result, rather than a pattern observed within this specific dataset. Further, language throughout this text should be clearly and accurately edited to reflect this actuality.

Author Response

Please see the attachment for our response.

Author Response File: Author Response.docx