## 5 Conclusions  
Our study demonstrated the high but imperfect test-retest reliability of a specific AEFEA system--FR8. As the second main finding, we demonstrated that repeated analyses by FR8 can, in some cases, lead to the \"stabilization\" of datasets. Thirdly, the test-retest differences did not influence the patterns of cross-emotion and cross-group effects and interactions. Thus, our study does not question the validity of previous results gained by AEFEA technology. Finally, no specific pattern of test-retest reliability emerged in the group of children with ASD. As a first exploration of the issue, our study leaves several key questions open about generalizing our results across AEFEA systems, subject groups, emotions, and emotion intensity patterns. Therefore, there are questions to be explored: whether imperfect test-retest reliability and the occasional \"stabilization\" effect are specific to FR8, or whether other AEFEA systems also show them; whether these phenomena are specific to our white/Caucasian child-aged sample(s) or not; and whether they arise on inputs with other emotions and/or emotion intensity patterns significantly different from those used in this study. Although the test-retest emotion intensity differences were small, and the imperfect test-retest reliability did not have an essential effect on group-level emotion intensity differences, it may have methodological significance when shorter (sections of) data series are analyzed, and when overall intensity patterns of emotions are different from those found in this study. It also remains to be determined whether first-test data series are less or more valid than subsequent ones, and whether gaining \"stabilized\" datasets (i.e., reaching perfect test-retest validity by repeated analyses) increases the validity. Our results do not question the validity of previous results using AEFEA technology. Instead, they suggest that it is necessary to further explore and understand this key characteristic of AEFEA systems. Finally, we ask the following question: which aspects of the functioning of FR8 account for the high but imperfect test-retest reliability and may be significant for the further development of AEFEA technologies? Conceptualization, M.G., Z.B. and K.S. ; methodology, M.G., Z.B. and K.S. ; software, M.G. and Z.J. ; validation, M.G., Z.B. and K.S. ; formal analysis, M.G., Z.J., Z.B. and K.S. ; data curation, M.G., Z.J., Z.B. and B.B. ; writing--original draft preparation, [PERSON], [PERSON], [PERSON] and K.S. ; writing--review and editing, [PERSON], [PERSON], [PERSON] and K.S. ; visualization, [PERSON]; supervision, K.S. ; project administration, [PERSON]; funding acquisition, M.G. All authors have read and agreed to the published version of the manuscript. Various aspects of the present study and the underlying R&D project have been funded by a grant within the EIT ICT Labs Hungarian Node (PI: [PERSON], ELTE Eotvos Lorand University); a TAMOP grant co-financed by the European Union and the government of Hungary (TAMOP 4.2.1./B-09/KMR--2010-0003); the ELTE University Thematic Excellence Program 2020, supported by the National Research--Development and Innovation Office--TKP2020-IKA-05; the Social Innovation Laboratory (TINLAB) Project at ELTE University; and a fundraising campaign by the IndaGaleria (Budapest). The first, third, and fifth authors were supported via a research grant from the Hungarian Academy of Sciences, within its Content Pedagogy Research Program (2016-2021 period). The Foundation for the Development of Special Education (GYFA; Budapest) contributed to the funding of the research at several points. The study was conducted in accordance with the Declaration of Helsinki, and approved by the Institutional Research Ethics Committee of the Barczi GusztavFaculty of Special Needs Education, ELTE Eotvos Lorand University (protocol code KEB/2016/001 and date of approval: 3 February 2016). **Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.