Generational Differences in the Acceptance of Care Robots Among Portuguese Adults: Evidence from the Almere Model, ADL and IADL Frameworks

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript addresses a timely and highly relevant topic within the fields of healthcare, gerontology, human–robot interaction, and the digital transformation of care systems. The study examines generational differences in the acceptance of care robots among Portuguese adults by integrating the Almere Model with the Katz Activities of Daily Living (ADL) and Lawton–Brody Instrumental Activities of Daily Living (IADL) frameworks. The topic is well aligned with the scope of the journal, particularly in the context of European demographic ageing and the emerging discussions surrounding Industry 5.0 and Society 5.0. Furthermore, the study adopts an interdisciplinary perspective that combines technological, psychological, and healthcare-related approaches.

Nevertheless, the manuscript presents several important methodological, conceptual, and writing-related weaknesses that considerably limit its scientific quality in its current form. First, although the literature review is extensive and adequately covers the main concepts related to the acceptance of care robots, there is a lack of clear articulation between the theoretical framework and the proposed hypotheses. The hypotheses are formulated in a largely descriptive and exploratory manner, without being clearly derived from previous theoretical models or adequately justifying the expected generational differences. This weakens the internal coherence of the study and makes it difficult to identify its added value in relation to previous research.

The methodology section requires substantial revision. The sampling procedure presents important limitations regarding representativeness. A purposive sample was employed, with a marked overrepresentation of Generation Z participants, who account for more than half of the sample, whereas Generation Y and Baby Boomer participants are represented by considerably smaller subsamples. This imbalance may affect the robustness of the intergenerational comparisons and should be explicitly acknowledged as a limitation. Furthermore, the recruitment of university students from specific academic disciplines introduces a significant selection bias that restricts the generalizability of the findings.

Another concern is the absence of information regarding the psychometric properties of the instruments employed. Although the manuscript reports the use of the Almere Model, the Katz Scale, and the Lawton–Brody Scale, no evidence is provided concerning internal consistency, construct validity, or cultural adaptation procedures for the Portuguese context. Given that part of the study relies on data reduction through principal component analysis, it is essential to provide detailed information regarding factor loadings, explained variance, extraction criteria, and reliability coefficients for each identified component.

The statistical strategy also presents several limitations. The authors conduct a large number of univariate ANOVAs for individual items, substantially increasing the risk of Type I error. Multivariate analytical procedures or more stringent corrections for multiple comparisons would have been more appropriate. Moreover, effect sizes are not reported, making it difficult to assess the practical significance of the observed differences. The interpretation of the results relies almost exclusively on statistical significance, which is insufficient according to current methodological standards.

The presentation of the results is excessively descriptive and, in some cases, repetitive. Several tables are lengthy and contain large amounts of statistical information that are difficult to interpret. The authors are encouraged to synthesize the main findings using more concise tables and to incorporate effect size measures. Additionally, some claims presented in the manuscript are not always sufficiently supported by specific analyses. For instance, the conclusion that Generation Z exhibits higher levels of anxiety and fear toward care robots would require a more comprehensive discussion of possible explanatory factors and potential confounding variables.

The discussion section is arguably the weakest part of the manuscript. Although the findings are partially linked to previous studies, the interpretation remains largely descriptive and lacks critical depth. Greater attention should be paid to the sociocultural implications of the results, particularly considering that some findings challenge common assumptions regarding so-called “digital natives.” Likewise, the practical implications for care robot design, healthcare practice, and public policy deserve a more detailed and critical discussion.

Numerous issues related to academic writing in English are also evident throughout the manuscript. Grammatical errors, unnatural sentence constructions, terminological inconsistencies, and expressions that do not conform to international scientific writing standards are frequently observed. Several sections would benefit from thorough professional language editing before the manuscript can be considered for publication.

Additionally, the manuscript still contains portions of the journal template instructions within the Materials and Methods section. This indicates shortcomings in manuscript preparation and insufficient proofreading prior to submission. These elements should be removed before further consideration.

Among the strengths of the study, it is worth highlighting the relatively original integration of the Almere Model with the ADL and IADL frameworks, the social relevance of the topic, and the interesting findings regarding differential acceptance of robots according to the type of caregiving task. The results showing greater acceptance of robots for instrumental tasks than for intimate caregiving activities are consistent with the international literature and provide valuable evidence within the Portuguese context.

The following recommendations are provided to assist the authors in improving the manuscript:

1. Strengthen the theoretical framework and derive the hypotheses more explicitly from previous literature.

2. Provide a stronger justification for the sampling procedure and explicitly discuss the limitations associated with the sample composition.

3. Report evidence of validity and reliability for all instruments used in the study.

4. Present detailed results of the factor analysis, including factor loadings, explained variance, and internal consistency indices.

5. Report effect sizes and reconsider the statistical strategy to better control for multiple comparison errors.

6. Substantially deepen the theoretical and practical discussion of the findings.

7. Expand the limitations section.

8. Remove all remaining journal template instructions from the manuscript.

9. Conduct a comprehensive professional revision of the academic English.

Comments on the Quality of English Language

The manuscript would benefit from substantial English language editing. Numerous grammatical errors, awkward sentence constructions, inconsistent terminology, and non-native expressions are present throughout the text, which at times hinder readability and comprehension. Several sections contain imprecise wording and stylistic issues that reduce the clarity of the arguments and the overall scientific presentation. In addition, some paragraphs are repetitive and would benefit from improved organization and conciseness. A thorough professional revision by a native English speaker or a specialized academic editing service is strongly recommended before publication.

Author Response

We thank Reviewer 3 for recognising the originality and relevance of the study.

 

Hypotheses

Comment

Better derive hypotheses from theory.

Response

Implemented.

The hypotheses were reformulated as directional hypotheses directly derived from:

• Almere Model;
• Human–Robot Interaction;
• ADL/IADL literature.

 

Sampling

Response

The rationale for purposive sampling is now fully explained and its limitations explicitly acknowledged.

 

Psychometric properties

Response

Expanded substantially.

 

Statistical analysis

Response

The revised manuscript now includes:

• reliability;
• PCA;
• effect sizes;
• multiple comparisons;
• improved statistical reporting.

 

Results

Comment

Too descriptive.

Response

The Results section was rewritten to focus on principal findings while avoiding unnecessary repetition.

 

Discussion

Comment

Needs greater depth.

Response

Implemented.

The Discussion now includes:

• sociocultural implications;
• implications for robot design;
• implications for healthcare practice;
• implications for public policy;
• critical interpretation of Generation Z findings.

 

Limitations

Response

Expanded.

 

English

Response

The entire manuscript was professionally revised to improve grammar, style and scientific writing.

 

Journal template remnants

Response

Removed.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

• The topic is timely and relevant, addressing an important issue in healthcare robotics and ageing societies. The integration of the Almere Model with the Katz ADL and Lawton–Brody IADL frameworks provides a useful contribution.
• The manuscript contributes empirical evidence on generational differences in the acceptance of care robots in Portugal. However, the novelty should be articulated more clearly by comparing the findings with recent international studies published in 2025–2026. Recent systematic reviews have shown that older adults generally prefer robots for instrumental tasks, companionship, and human-like interaction while remaining hesitant about intimate care activities, which closely aligns with the present findings.
• Include a stronger comparative analysis with recent literature.
• The methodology requires improvement. The purposive sampling strategy resulted in an imbalanced sample with an overrepresentation of Generation Z, limiting the generalizability of the findings. Justify the sampling strategy more clearly.
• Provide additional details regarding questionnaire validation, construct reliability, and the rationale for Principal Component Analysis, including factor loadings and variance explained.
• The discussion should avoid overinterpreting the “uncanny valley" phenomenon, as it was not directly measured in the study.
• The conclusions are generally supported by the presented results but should be more cautiously framed, avoiding causal interpretations due to the cross-sectional design.
• The reference list is appropriate but should incorporate more recent (2025–2026) systematic reviews and meta-analyses on socially assistive robots, AI-assisted elder care, technology acceptance, and ethical issues in healthcare robotics.
• Tables are informative but overly detailed. Simplifying the statistical tables and adding effect sizes would improve readability. Figures should be presented in higher resolution with clearer legends and captions.

 

Author Response

We thank Reviewer 1 for the positive evaluation of the manuscript and the constructive suggestions.

Comment 1

The novelty should be articulated more clearly and compared with recent international studies.

Response

Thank you for this suggestion.

The Introduction and Literature Review were substantially revised to clarify the manuscript's scientific contribution.

The revised manuscript now explicitly highlights that the study is among the first to integrate:

• the Almere Model;
• the Katz ADL framework;
• the Lawton–Brody IADL framework;

to analyse generational differences in care robot acceptance.

Furthermore, numerous international studies published during 2024–2026 were incorporated throughout the Literature Review and Discussion.

 

Comment 2

Strengthen the comparative discussion with recent literature.

Response

Implemented.

The Discussion now compares our findings with recent international evidence regarding:

• task-dependent robot acceptance;
• emotional trust;
• anthropomorphism;
• Industry 5.0;
• Human–Robot Interaction;
• socially assistive robots.

Several new systematic reviews and empirical studies were incorporated.

 

Comment 3

Justify purposive sampling.

Response

Implemented.

The Methods section now provides a clearer rationale for purposive sampling.

The manuscript explains that Generation Z participants were intentionally recruited from university programmes closely related to future AI adoption (healthcare, hospitality and marketing), while explicitly acknowledging the resulting limitations for representativeness.

 

Comment 4

Provide questionnaire validation and PCA details.

Response

Implemented.

The revised manuscript now reports:

• questionnaire development;
• reliability analysis;
• PCA procedure;
• extraction criteria;
• KMO;
• Cronbach's alpha;
• explained variance;
• factor loadings.

 

Comment 5

Avoid overinterpreting the uncanny valley.

Response

Implemented.

References to the Uncanny Valley have been substantially moderated.

The manuscript now presents this explanation only as a possible interpretation supported by previous literature rather than as a direct finding of the present study.

 

Comment 6

Avoid causal interpretations.

Response

Implemented.

Throughout the manuscript, causal language has been replaced by more cautious wording such as:

• "suggests";
• "is associated with";
• "may indicate";
• "is consistent with."

 

Comment 7

Update references.

Response

Implemented.

The bibliography has been substantially expanded with recent publications on:

• socially assistive robots;
• Human–Robot Interaction;
• AI in elder care;
• Industry 5.0;
• Society 5.0;
• technology acceptance.

 

Comment 8

Simplify tables.

Response

Implemented where possible.

Tables were streamlined and narrative interpretation was improved.

Effect sizes were added where appropriate.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors The evaluation of the article is as follows. This study aims to examine the levels of acceptance of care robots among adults in Portugal and the intergenerational differences in this acceptance. The research focuses on filling a significant gap in the literature by integrating the Almere model which measures technology acceptance with scales for activities of daily living and instrumental activities of daily living (IADL), which determine levels of geriatric functional independence. The study’s key finding reveals that acceptance of robotic assistance is highly task-dependent and that, contrary to popular belief, Generation Z often considered “digital natives” reported higher levels of anxiety, fear, and hesitation toward care robots compared to Generations X and the Baby Boomers.

• Generation Z alone accounts for a very large proportion 56.7% of the total 217 valid surveys. In contrast, the Generation Y sample is limited to only 20 participants. This extreme imbalance in participant numbers seriously compromises the power and reliability of ANOVA analyses and post-hoc tests involving cross-group comparisons.
• Virtually none of the participants have had direct interaction experience with an actual social assistive robot. Conducting the evaluations entirely based on hypothetical scenarios and visuals may fail to accurately reflect actual acceptance behavior and could lead to bias in the responses.
• The text states that the Q17.14 variable was excluded from the analysis, but the theoretical or statistical rationale for this decision has not been sufficiently explained.
• The fact that the study is limited solely to the Lisbon Metropolitan Area makes it difficult to generalize the results to the sociocultural structure of Portugal as a whole.

Author Response

We sincerely thank the reviewer for the careful evaluation of our manuscript and for the constructive comments. Please check the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The paper examines a relevant subject: generational disparities in the acceptability of care robots within the framework of aging societies, Industry 5.0, Society 5.0, and human-robot interaction in elder care. The integration of the Almere Model with ADL and IADL-related activities is appropriate and offers a useful perspective on task-dependent acceptance.

The findings are interesting, particularly the lower acceptance of robots for intimate care activities and the reported higher levels of fear or discomfort among Generation Z. However, the manuscript requires substantial revision to improve methodological clarity, statistical reporting, consistency, and the cautious interpretation of results.

The abstract summarizes the study well, but it should report the sample size, sampling strategy, and geographical limitation. Claims should be moderated to avoid implying national representativeness.

The Introduction provides a relevant rationale based on population ageing, care needs, and technological transformation. However, the research objective should be stated more clearly and aligned with the analyses presented. The manuscript mentions gender, age, and income differences, but the results mainly focus on generational comparisons.

The Literature Review covers relevant topics, including Industry 5.0, Society 5.0, care robots, technology acceptance, the Almere Model, trust, ethics, and ADL/IADL frameworks. However, it is somewhat broad and should be more focused on the specific research questions.

The discussion of the “uncanny valley” should be presented cautiously, since the study measures fear and intimidation but does not directly test robot appearance realism or uncanny valley effects.

Materials and methods—This section needs some clarification. The authors should provide more details on recruitment, data collection period, inclusion criteria, questionnaire development, translation/adaptation procedures, and missing data handling.

The sample is purposive and strongly imbalanced across generations, with Generation Z overrepresented. This limitation should be explicitly acknowledged.

The statistical methods are generally relevant, but reporting should be improved. The use of ANOVA on Likert-scale items and unequal group sizes should be justified, and non-parametric robustness checks could strengthen the analysis.

The authors should report effect sizes, confidence intervals where appropriate, and corrections for multiple comparisons. PCA reporting also needs clarification, including the number of extracted components, extraction criteria, explained variance, factor loadings, and reliability values.

The description of KMO and Cronbach’s alpha should be corrected, as KMO assesses sampling adequacy for factor analysis, while Cronbach’s alpha assesses internal consistency.

The results support the main conclusion that robot acceptance is task-dependent. Respondents appear more accepting of robots for practical activities such as cleaning, laundry, shopping, meal preparation, and transportation, and less accepting of robots for intimate care activities such as bathing, toileting, dressing, feeding, and incontinence care.

The finding that Generation Z reports higher fear or intimidation toward robots is interesting, but it should be interpreted cautiously due to the sample structure and absence of direct robot interaction.

Tables and figures need clearer formatting. Generational labels and age thresholds should be made consistent throughout the manuscript. Some interpretations should be checked against the actual group means, especially where the text states that all groups agree or disagree.

The Discussion is relevant and connects the findings with care ethics, trust, cultural expectations, and task intimacy. The distinction between robots as complementary tools and robots as replacements for human caregivers is appropriate.

Causal explanations should be moderated. The manuscript should avoid suggesting that Generation Z’s discomfort is caused by the uncanny valley unless this is presented as a hypothesis rather than a demonstrated finding.

The manuscript acknowledges some limitations, but this section should be expanded. The authors should explicitly mention the non-representative sample, unequal generational group sizes, reliance on hypothetical self-reported attitudes, lack of direct interaction with robots, and absence of qualitative data explaining the reasons for acceptance or resistance.

The Conclusion should clearly state that the findings are based on a purposive urban sample and should not be generalized to all Portuguese adults or all older adults.

Main recommendations:

1. Clarify the study scope, sample structure, and limits of generalizability.
2. Ensure consistency in generational labels and age groups.
3. Improve statistical reporting with effect sizes, multiple-testing correction, and robustness checks.
4. Clarify questionnaire adaptation and validation.
5. Improve PCA and reliability reporting.
6. Moderate claims regarding uncanny valley, cultural explanations, and national-level conclusions.
7. Improve the formatting and clarity of tables and figures.
8. The reference list is limited; the authors should update the literature review with more post-2022 references on care robots, human–robot interaction, and technology acceptance in elder care.
9. Revise the manuscript for English language, grammar, and academic style.

Author Response

We sincerely thank Reviewer 2 for the comprehensive methodological review.

 

Abstract

Comment

Include sample size, sampling strategy and geographical limitation.

Response

Implemented.

The Abstract now explicitly reports:

• sample size;
• purposive sampling;
• Lisbon Metropolitan Area;
• limited generalisability.

 

Introduction

Comment

Clarify objectives.

Response

Implemented.

The Introduction now presents a single, clearly stated research objective fully aligned with the empirical analyses.

 

Literature Review

Comment

Focus more closely on research questions.

Response

Implemented.

The Literature Review was reorganised, shortened and rewritten to improve logical flow.

Each subsection now directly supports the hypotheses.

 

Methods

Comment

Provide recruitment, inclusion criteria, questionnaire development and missing-data handling.

Response

Implemented.

The Methods section has been expanded accordingly.

 

Sample imbalance

Response

Explicitly acknowledged as a limitation.

 

Statistical reporting

Comment

Improve ANOVA justification.

Response

Implemented.

Additional justification is now provided regarding:

• ANOVA assumptions;
• homogeneity tests;
• post hoc procedures;
• robustness.

 

PCA reporting

Response

Expanded considerably.

 

KMO and Cronbach

Response

Corrected.

The manuscript now clearly distinguishes:

• KMO → sampling adequacy
• Cronbach's alpha → internal consistency

 

Results

Comment

Interpret cautiously.

Response

Implemented.

All interpretations were revised.

 

Tables

Response

Formatting improved.

Generational labels were standardised throughout the manuscript.

 

Discussion

Comment

Avoid causal statements.

Response

Implemented.

 

Limitations

Comment

Expand.

Response

Implemented.

The revised manuscript now discusses:

• purposive sampling;
• unequal group sizes;
• hypothetical attitudes;
• lack of robot interaction;
• absence of qualitative data.

 

English

Response

The manuscript underwent comprehensive language editing and stylistic revision.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have satisfactorily addressed the comments and suggestions raised during the previous round of review. The revisions made have improved the clarity, methodological transparency, and overall quality of the manuscript.

In my opinion, the manuscript is now suitable for publication in its current form. I have no further comments or suggestions.

Congratulations to the authors on their work.

Comments on the Quality of English Language

The English language is clear, appropriate, and suitable for scientific publication. The manuscript is generally well written and the revisions have further improved its readability. No additional language revisions are required.

Author Response

Dear Reviewer,

We thank you all the attention this piece of literature has deserved.

Best regards

Reviewer 2 Report

Comments and Suggestions for Authors

The paper can be accepted in present form.

Author Response

Dear reviewer,

Following your recommendation that only minor editorial changes should be made at this stage, we have limited our revisions to formatting improvements only. In particular, we adjusted the layout of tables and figures to ensure that they are properly displayed within single pages whenever possible, thereby improving readability and presentation. No changes have been made to the scientific content, analyses, results, conclusions, authorship, or interpretation of the findings.

Best regards,

Reviewer 4 Report

Comments and Suggestions for Authors

Thank you for revising the manuscript and for providing a detailed response to the reviewers’ comments. The revised version shows clear improvements in methodological description, experimental reporting, reproducibility, and the presentation of the study’s contribution. The authors have also moderated the claims regarding interpretability and clinical relevance and have expanded the discussion of the study limitations. Some aspects, including external validation, calibration analysis, ablation studies, and comparison with pathology foundation models, remain outside the scope of the current work but are now appropriately acknowledged. Overall, the authors have adequately addressed the main concerns raised during the previous review round, and the manuscript is now suitable for publication in its revised form.

Author Response

Dear Reviewer,

We thank you all the attention this piece of literature has deserved.

Best regards