Preservice Teachers Training with Avatars: A Systematic Literature Review of “Human-in-the-Loop” Simulations in Teacher Education and Special Education

Abstract

Simulations have been introduced in teacher training in recent times to prepare preservice teachers for teaching. This review aims to search for and analyze studies on the use of human- and computer-based virtual simulations (i.e., where humans act with avatars) in teacher training, in order to better understand how the use of such simulations may support the development of preservice teachers, as well as to identify potential gaps in the literature and suggest potential routes for future research. A categorization of 26 included articles shows that 22 articles investigate rule management competence, 3 articles investigate didactic competence, and 1 article investigates relational competence. Research about preservice teachers’ experience of virtual simulations gives an overall positive picture. The studies included show several important advantages of virtual simulations. The disadvantages that are described in the studies are almost exclusively caused by technical limitations.

1. Introduction

Teaching is a complex and sometimes unpredictable activity, where teachers meet a great diversity of students with different personalities, goals, and educational needs. Consequently, there is a need for prospective teachers to experience a range of different situations and students during their teacher education, to prepare them for their future profession. This is one of the reasons for field-based education being an important part of teacher education. However, field-based teacher education also has several important limitations. For example, due to the sometimes very specific circumstances at the schools where preservice teachers have their practicum, an individual preservice teacher may not have the opportunity to experience the desired breadth of situations and/or students as part of her/his field-based teacher education. This may result in novice teachers not having adequate training for handling complex pedagogical situations, which is particularly problematic in relation to vulnerable students, such as students in need of additional support, who risk being harmed by inappropriate actions. As noted by Berliner [1] in the 1980s, these limitations to field-based teacher education sometimes make “laboratory settings” a more fruitful alternative and an important complement to authentic classroom experiences.

Recently, virtual simulations have emerged as an innovative approach, in which technology is used to recreate certain aspects of reality to improve the education process [2]. Several advantages of using virtual simulations have been suggested, such as enabling preservice teachers to practice in controlled and safe environments without the risk of harming students [3,4,5], and the possibility of exploring different solutions to complex pedagogical situations. However, although the use of, and research on, virtual simulations have increased in teacher education as a means to better prepare preservice teachers to teach in real classrooms [3,4,5,6,7], several important questions are still left unanswered.

In this review, we, therefore, search for and analyze studies on the use of human- and computer-based virtual simulations (i.e., where humans act with avatars) in teacher education, including special education, in order to better understand how the use of such simulations may support the development of preservice teachers, as well as to identify gaps in the literature and suggest potential routes for future research [8].

1.1. The Use of Simulations in Practice-Based Teacher Education

This review is based in a practice-based teacher education (PBTE) tradition. In contrast to approaches that primarily focus on theoretical knowledge about teaching and learning, PBTE is an approach that emphasizes authentic experiences of teaching (e.g., [9,10]). It is important to note, however, that although apprenticeship and non-formal learning are key aspects of such an approach, it is the combination of campus-, and field-based experiences that is assumed to provide the most meaningful preparation for novice teachers. There are several reasons for this, but the most serious point is that a too strong emphasis on field-based education might promote socialization into an unwanted occupational culture and outdated practices [11]. Furthermore, it has been shown that workplace-based training does not necessarily support pre-service teachers in reflecting on their practice see (e.g., [12]). These potential drawbacks of field-based teacher education suggest not only that a combination of campus- and field-based experiences are necessary for the successful preparation of preservice teachers, but also that a distinction needs to be made as to which competencies are best learned through participation in workplace settings and those more properly learned in other settings.

As a consequence, although this review builds on the assumption that professional development that provides experiences more closely associated with the professional context may be in a better position to facilitate skill acquisition, and to more successfully support the improvement of professional practices (e.g., [13]), such efforts do not necessarily have to be situated in an actual workplace or involve direct participation. Practical situations can also be experienced vicariously, as a way to provide a common ground for discussion and reflection, which opens the door for the use of different types of simulations.

1.2. Different Types of Simulations

Previously, traditional role-play and video have been important tools for simulating professional practice, allowing preservice teachers to experience a greater range of situations and students—experiences which may then be analyzed and discussed in relation to professional practice. More recently, however, virtual simulations have emerged as a novel approach, providing other possibilities for teacher education.

There is a wide vocabulary to describe simulation of teaching. According to Howell and Mikeska [4], the most common description is that simulations serve as simplified models of reality that contain elements, behaviors, and processes that have equivalents in the real world. Simulations are consciously different from the real world, and they are not a substitute for authentic teaching practice. Instead, they are designed to control and reduce complexity for educational purposes. Therefore, Howell and Mikeska [4] suggest that simulations of teaching could be described as “the subset of approximations in which a teacher or prospective teacher is engaged in doing the interactive work of teaching […] simulation the experience engages the participant in cognitive and enacted responses that mimic those of the classroom” (p. 11).

It is common to divide simulations into three types, based on the specific interaction between humans and computers used: (1) human-based simulations, where a human acts with a human (e.g., Live simulation [7]); (2) human- and computer-based simulations, where a human acts with an avatar (e.g., TeachLivE™ [3]; Available online: https://sites.google.com/view/teachlive/home?authuser=0, accessed on 20 June 2023); and (3) computer-based simulations, where a human acts as an avatar with an avatar (e.g., Second Life [3]) (see

Table 1. Different types of simulations with examples.

Simulation Type 1: Human-Based Simulation (a Human Acts with a Human)	Simulation Type 2: Human- and Computer-Based Simulation (a Human Acts with an Avatar)	Simulation Type 3: Computer-Based Simulation (a Human Acts as an Avatar with an Avatar)
Online learning.1 Online technology is used to teach students in a physical environment [3].	Immersive simulations. SIM School is a game environment in which pre-service teachers play and provide feedback on their decisions. TLE TeachLivE™ is a fully developed immersive simulator with a mixed-reality, avatar-based simulation environment [3].	Second Life is a game in which the pre-service teacher attempts presence by embodying an avatar who interacts with other human generated avatars [3].
Live simulation. Real players are given roles in their actual environment [7].	Virtual simulation. Real players use simulation systems in an artificial environment [7].	Constructive simulation. Real players act as virtual players with programmed avatars in artificial environment simulation systems [7].
The clinical simulation model. A human-based simulation which involves the participation of a professional actor [2].	Mixed reality/Immersive simulation. Interactions take place between a human and a digital figure [2].	Computer-based simulation. A digital figure is used, often in the form of an avatar [2].

¹ Commonly used names are given in italics.

).

The specific focus of this review is human- and computer-based simulations, in which humans act with avatars. These simulations use “human-in-the-loop” (HIL) methods, where digital avatars are controlled by humans in real time. This gives the possibility to adjust the simulation in relation to the specific needs of a particular person, group, or situation, as well as to support an authentic experience. Authenticity is of particular interest in this context, as it may help the users to become immersed in the experience and act more naturally. In contrast to computer-based simulations, where humans act as avatars, HIL simulations allow the users to act as they would in an unsimulated situation. HIL is thus compatible with PBTE, by facilitating teachers’ engagement with their teaching practice and reflecting on it [4]. Furthermore, this field is growing fast, and more research is needed in this domain [4,14].

1.3. Focus and Findings of Previous Research Reviews

When virtual simulations were first established in teacher education, Dieker, Rodriguez, Lignugaris/Kraft, Hynes and Hughes [3] published a research overview that provided a summary of the evolution of simulations in the field of teacher education. The overview also included a specific example of the work with virtual simulations in teacher education. One conclusion drawn was that a virtual environment may improve preservice teachers’ pedagogical and content knowledge. The safe and controlled environment makes it possible for preservice teachers to practice repeatedly, and to correct errors with avatars, instead of making mistakes with real students.

Another overview, by Kaufman and Ireland [6], provides examples of simulations. Based on the research included, simulations are described as a tool to augment the practicum experience. It is also noted that simulations are often used with a cycle of practice, feedback, reflection, and repeated practice. Overall, it is found that the tool provides opportunities for preservice teachers to practice specific skills and interpersonal behaviors.

Theelen et al. [15] reviewed research on the connection between preservice teachers’ interpersonal competence, well-being, and simulations. They also mapped learning experiences, possibilities, and limitations of simulations. Most of the studies included described the positive effects of simulations on preservice teachers’ classroom management and teaching skills. However, the research did not report specifically on interpersonal competence. Possibilities with simulations found were that they have positive effects on preservice teachers’ classroom management and teaching skills. Limitations with simulations were mainly described as being of a technical nature, such as malfunctioning audio or video.

McGarr [5] explored the use of virtual simulations in teacher education, with a focus on how virtual simulations develop pre-service teachers’ behavior and classroom management skills. It was found that there are many benefits of using virtual simulations in teacher education, for example bridging the gap between theory and practice and facilitating pre-service teachers’ development in a controlled and safe environment. A disadvantage with virtual simulations that emerged was that they may simplify the nature of behavior to fit common stereotypes. By using stereotypes of students and their behavior, there is a risk that pre-service teachers are not challenged in their critical approaches and interpretations of classroom events.

Ersozlu, Ledger, Ersozlu, Mayne and Wildy [14] investigated a specific mixed-reality simulated classroom technology, TeachLivE™, to identify trends and potential gaps in the research. Integration of TeachLivE™ in teacher education and instructional skills development was the most common research focus. The conclusion drawn was that TeachLivE™ is a genuine alternative to prepare preservice teachers for classroom contexts. The research examined both preservice teachers’ and preservice special education teachers’ development. The most common focus was on preservice teachers, but studies focusing on in-service teachers are increasing.

In summary, the findings from previous reviews support the idea that virtual simulations may be used to complement or augment preservice teachers’ practicum experiences. As shown by the research reviewed, a number of different teaching skills have been seen to improve when practiced through virtual simulations. Important to note in relation to these findings, is that virtual simulations allow for cycles of practice, feedback, reflection, and repeated practice [6]. Such a methodology is difficult to arrange when teaching in authentic classrooms, but may very well account for much of the observed improvements among preservice teachers. This suggests that future studies should seek to make cycles of practice, feedback, reflection, and repeated practice an integral part of the virtual simulation methodology.

Another recurring finding from previous reviews is that virtual simulations offer a safe and controlled environment for the abovementioned cycles of practice, feedback, reflection, and repeated practice. This may also help to explain the observed improvements among preservice teachers, as they are given the opportunity not only for repeated practice, but to practice their teaching skills in a context where they do not have to worry about their mistakes affecting any real students.

Limitations and disadvantages of virtual simulations is another aspect covered by previous reviews, but mostly in technical terms. Still, it is likely that there are several limitations to simulated students, that affect the pedagogical practices of the preservice teachers (e.g., which teaching strategies possible to use) and to what extent they perceive the situation as sufficiently authentic to engage properly with the avatars. As noted by McGarr [5], virtual simulations may also simplify the behavior of students to fit common stereotypes, which may, in turn, give a false sense of security among the preservice teachers.

1.4. Aim and Research Questions

The aim of this review is to search for and analyze studies on the use of “type 2 simulations” (i.e., where humans act with avatars) in teacher education, including special education, in order to better understand how the use of such simulations may support the development of preservice teachers, as well as to identify gaps in the literature and suggests potential routes for future research.

As can be seen from previous reviews, even though research on virtual simulations have reported positive findings in relation to preservice teachers’ teaching skills, there are several questions left unanswered, some of which will be addressed in the current review. First, it is not clear from previous research which aspects of teacher competence that virtual simulations have intended to support the development of. This review therefore aims to identify which such aspects have been addressed, to see if virtual simulations have different potential for different aspects of teachers’ work. In this part of the analysis, we will use the categorization as suggested by Nordenbo et al. [16], who categorized teacher competence into three basic sub-competences: rule management competence, didactic competence, and relational competence. Rule management competence is about providing structure and establishing rules for the pedagogical work in the classroom, for example explicit rules for how to behave, making the students (as a group) work in an orderly fashion that promotes student achievement and progression. The teacher also focusses the attention of the class on the syllabus, follows up on students’ learning, and gives rapid and corrective feedback. Didactic competence is characterized by the teacher being able to use different teaching methods, materials, and approaches, more or less closely tied to the subject in question. The teacher also challenges the students cognitively, establishes clear teaching goals, and organizes activities to promote student learning. Relational competence is the teacher’s capability to support, activate, and motivate individual students and develop relationships based on respect, tolerance, and empathy. A categorization based on these three sub-competences will show which competences are represented in the included studies.

As part of the ambition to identify which such aspects of teacher competency that have been addressed, this review will also include research on special education, since—as noted above—one of the main arguments for using simulations is that it enables preservice teachers to practice in controlled and safe environments without the risk of harming students. The situations where this is most acute are situations that involve vulnerable students, such as students in need of additional support. In some sense, the most important use of virtual simulations may therefore be in relation to special education.

In addition to identifying different aspects of teacher competence, the current review focus specifically on preservice teachers’ experiences of participating in virtual “human-in-the-loop” simulations, as well as potential disadvantages for pedagogical practices, as these dimensions have important implications for the validity of conclusions drawn from preservice teachers’ performance in the simulation context.

Taken together, the research questions that guided this review are as follows:

• RQ1: Which competences do preservice teachers develop through practice in virtual “human-in-the-loop” simulations?
• RQ2: What are preservice teachers’ perceptions of virtual “human-in-the-loop” simulations?
• RQ3: What advantages and disadvantages of virtual “human-in-the-loop” simulations have been identified?

The review includes research on both teacher education and special education and unless otherwise stated the term “teacher education” includes both.

2. Materials and Methods

This overview has a configuring approach and searches for patterns and themes as a basis for the emergence of knowledge in relation to a phenomenon [17], in this case virtual simulations in teacher and special education programs. This approach makes it possible to include studies using qualitative as well as quantitative data, to interpret and understand the given phenomenon [17,18,19]. In this study, a systematic review is conducted, which involves systematically searching for, critically examining, and compiling the literature on a specific subject, so that the overview achieves a synthesis of data from previous empirical studies [20]. Reviewing the literature systematically makes it possible to gain knowledge on the breadth, purpose, and extent of the research on a specific area [17]. Systematic mapping is appropriate when the review seeks to map out and categorize research on a specific topic and to identify gaps in research to commission additional reviews or primary research. Systematic maps offer policymakers, practitioners, and researchers a transparent and explicit means to identify policy- and practice-relevant review questions. Through systematic maps, research can be characterized according to, for example, theoretical approaches or population groups examined. Important weaknesses with mapping reviews are that they are broad and descriptive, and this risks oversimplifying the relationship between research and findings. The extent of this risk depends on the degree of specificity of the coding process [8].

2.1. Initial Search

This systematic review is based on a comprehensive search using both Summon, an interface that compiles results from various databases, and searches in multiple individual databases like ERIC, Academic Search Premier, Web of Science, and Scopus. Searches were conducted in Summon on 7 September 2021 and in multiple individual databases on 28 September 2021 (

Table 2. Systematic search.

Databases	Search Dates	Thesaurus	Free Text	Search	Number of Articles	After Filtering (Peer-Reviewed Journal Articles Published in English)
Summon	7 September 2021	Educational science	“avatar*” OR “mixed-reality simulation” OR “virtual simulation” combined with “teacher education” OR “special education”.	(avatar*) AND ((“teacher education”) OR (“special education”)) AND ((“classroom simulation”) OR (“mixed-reality simulation”) OR (“virtual simulation”))	213	53
Academic Search Premier	28 September 2021		“avatar*” OR “mixed-reality simulation” OR “virtual simulation” combined with “teacher education” OR “special education”.	(avatar*) AND ((“teacher education”) OR (“special education”)) AND ((“classroom simulation”) OR (“mixed-reality simulation”) OR (“virtual simulation”))	1	1
ERIC	28 September 2021		“avatar*” OR “mixed-reality simulation” OR “virtual simulation” combined with “teacher education” OR “special education”.	(avatar*) AND ((“teacher education”) OR (“special education”)) AND ((“classroom simulation”) OR (“mixed-reality simulation”) OR (“virtual simulation”))	3	3
Scopus	28 September 2021		“avatar*” OR “mixed-reality simulation” OR “virtual simulation” combined with “teacher education” OR “special education”.	(avatar*) AND ((“teacher education”) OR (“special education”)) AND ((“classroom simulation”) OR (“mixed-reality simulation”) OR (“virtual simulation”))	4	3
Web of science	28 September 2021		“avatar*” OR “mixed-reality simulation” OR “virtual simulation” combined with “teacher education” OR “special education”.	(avatar*) AND ((“teacher education”) OR (“special education”)) AND ((“classroom simulation”) OR (“mixed-reality simulation”) OR (“virtual simulation”))	2	2

).

The process began with test searches for virtual simulations and teacher education, including special education, to gain knowledge on the terminology used in the field. By studying the reference lists in the articles found, it was possible to find additional articles on the subject [20]. In this way, the test searches led to an increased insight into the relevant terminology. Keywords were identified for the literature review. The search focused on two fields: virtual simulations and teacher education. The search terms used across all five databases were: “avatar*” OR “mixed-reality simulation” OR “virtual simulation” combined with “teacher education” OR “special education.” The searches on Summon differed from those on the other databases in that they were delimited to the subject area of “educational science.” The initial search resulted in 223 articles (213 in Summon, 1 in Academic Search Premier, 3 in ERIC, 4 in Scopus, and 2 in Web of Science).

2.2. Article Selection

The number of retrieved articles decreased when the search was limited to scientifically peer-reviewed journal articles published in English. A total of 62 articles were selected. After the removal of duplicates, 55 articles were left. The titles and abstracts of the 55 remaining articles were read. The following criteria were used to determine eligibility:

• Peer-reviewed journal articles published in English.
• Empirical studies.
• Studies on preservice teachers and/or preservice special teachers.
• Preservice teachers and/or preservice special teachers interacting as themselves with avatars.

The inclusion criteria were created based on simulations of type 2 above, which is a human- and computer-based simulation in which a human acts with an avatar. This means that simulation types 1 (human-based simulation where a human acts with a human) and 3 (computer-based simulation where a human acts as an avatar with an avatar) were excluded (see Table 1). After reading 55 titles and abstracts, 37 documents were excluded for not meeting the inclusion criteria.

An inter-rater agreement estimation was carried out to ensure the validity of the articles included. Another researcher participated in the abstract screening process and read the title and abstract of the 55 articles independently and used the inclusion criteria to determine eligibility. With the exception of one article, the outcome was identical in both cases. The disagreement was settled through a consensus decision, based on a reading of the entire article. After the inter-rater agreement, 18 relevant abstracts were selected, and the full articles were read (Figure 1).

In addition, a snowball search strategy was carried out by searching reference lists of included articles for other relevant records. Snowball searching was conducted to increase the rigor and quality of the systematic review. An inter-rater agreement estimation was carried out to ensure the validity of the articles included from the reference lists, similar to the database search. Another 8 articles were selected from the snowball search. In total, the review includes 26 articles.

2.3. Categorization of Articles

The following data were extracted from the articles: author and year of publication, location of study, journal of publication, research focus (after extracting research questions or stated research purpose verbatim), framework, method (qualitative, quantitative, or mixed), data collection measures (survey questionnaires or rating scale, interview, observation or field notes, focus group discussions), education (teacher or special education), context (physical or digital), and findings (extraction of the verbatim description of main findings). For more information on the data from each article, see

Table A1. Overview of included studies.

Nr.	Authors and Year of Publication	Location	Journal of Publication	Research Aims	Framework	Method	Data Collection Measure	Edu-cation	Context	Findings
1.	Ely et al., 2018	USA	Journal of Digital Learning in Teacher Education	Examine uses of TLE TeachLivE classroom simulation to (a) improve preservice teachers’ practical knowledge of CSR and (b) prepare preservice teachers to implement CSR.	Social cognitive theory	Quantitative	Survey questionnaire or rating scale	Teacher education	Physically	Both groups significantly improved their knowledge of CSR practices after experiencing the simulation, and all participants indicated an overall positive perception of simulation to prepare teachers.
2.	Spencer et al., 2019	USA	Journal of Educational Computing Research	Measuring participants’ opinion of the value of having a co-teacher and indicating their perception of the usefulness and realism of role-play and mixed-reality.	Not explicitly stated	Quantitative	Survey questionnaire or rating scale	Teacher education and special education	Physically	The students considered the Mixed-reality simulation significantly more realistic and more useful than role-playing. Students who used the simulator developed their assessment of co-teaching to a much greater degree than those who participated in the role-play.
3.	Peterson-Ahmad, 2018	USA	Education sciences	Investigate how virtual simulations, in combination with instructional coaching from the mentor teacher preparation faculty, could be used to transform early learning experiences with pre-service educators, specifically teaching how to effectively provide opportunities to respond so that teachers provide stimuli that warrant student responses.	Not explicitly stated	Quantitative	Survey questionnaire or rating scale, observation	Special education	Physically	Both groups had some increase in opportunities to respond (OTR) regardless of whether they received instructional coaching. All participants received OTR over the suggested speed, indicating that practice through simulations with repeated teaching attempts can be effective in learning basic aspects of teaching.
4.	Vince Garland et al., 2016	USA	Teacher Education and Special Education	Examine the fidelity of the implementation of teachers’ use of system-of-least prompts (SLP) when provided with individualized clinical coaching (ICC) in TLE.	Not explicitly stated	Quantitative	Survey questionnaire or rating scale, observation	Special education	Physically	The results suggest that ICC in simulation was effective in increasing the fidelity of implementation of the participants’ use of SLP.
5.	Landon-Hays et al., 2020	USA	Education sciences	Integrate authentic technology in educator preparation programs (EPPs) to explore how Mursion can support teacher candidates in improving their teaching skills and in practicing specific teaching skills/strategies.	Not explicitly stated	Mixed method	Survey questionnaire or rating scale, focus group discussion, and self-reflection	Teacher education and special education	Physically	A majority increased their perceived self-efficacy in explicitly explaining and modeling content between initial and final sessions. The students’ increased use of high leverage practices related to strategic teaching, collaboration, differentiation, and providing feedback.
6.	Dawson & Lignugaris/Kraft, 2017	USA	Teacher Education and Special Education	Investigate the effectiveness of TLE intervention sessions on preservice special educators’ development of foundation target skills in the behavior and academic domains (i.e., specific praise, praise around, and error correction) and the extent to which they generalized these skills to authentic classrooms.	Situated learning	Quantitative	Observation, self-reflection	Teacher education and special education	Physically	The teachers improved the delivery of their target skills in the virtual simulation. They generalized performance to real classroom settings with varying levels of skill. This shows that virtual simulation is a promising tool for repeated exercises and feedback on basic teaching skills.
7.	Gundel & Piro, 2021	USA	Action in Teacher Education	Gain insight on the self-efficacy beliefs of pre-service teachers in a curriculum augmented with mixed reality simulation experiences.	Self-efficacy	Qualitative	Interviews, observation	Teacher education	Physically	The self-efficacy of students who engaged in simulations and feedback sessions was enhanced through enactive and vicarious learning, as well as opportunities to give and receive feedback, and by learning to manage one’s emotions.
8.	Larson et al., 2020	USA	Journal of Special Education Technology	Describe the implementation of TLE TeachLive™ in a university-based traditional teacher preparation program and to examine the feasibility and acceptability of mixed-reality simulation for use within teacher preparation as A supplement for students enrolled in either a classroom management or special education methods class.	The Action Review Cycle	Mixed methods	Survey questionnaire or rating scale, focus groups	Teacher education and special education	Physically	Most students considered the simulator an opportunity to practice behavior management techniques in a consequence-free environment. Implementers have opportunities to offset the anticipatory anxiety expressed by most participants.
9.	Hudson et al., 2019	USA	Rural Special Education Quarterly	Investigate the effects of mixed-reality teaching experiences on preservice teachers’ perceptions of their own readiness to manage a classroom.	Not explicitly stated	Mixed methods	Survey questionnaire or rating scale, self-reflection	Special education	Physically	The results indicated that experiences of virtual simulation were beneficial in increasing students’ perceptions of the ability to manage a classroom.
10.	Finn et al., 2020	Australia	Journal of International Students	Investigate how international students draw on their own cultural identity to reflect on their teaching practice in a simulated classroom in the Australian context.	Rodger’s framework	Quantitative	self reflection	Teacher education	Online	Simulated teaching experience can support and improve reflective practice among pre-service teachers. Virtual simulations provide university educators with an important diagnostic tool to identify gaps in support.
11.	Gundel et al., 2019	USA	The Teacher Educator	Examine the effects of mixed reality simulations on preservice teachers’ sense of self-efficacy.	Self-efficacy	Quantitative	Survey questionnaire or rating scale	Teacher education	Physically	The development of self-efficacy was evident for total exposure for 30 minutes with mixed reality simulation experiences.
12.	Rosati-Peterson et al., 2021	USA	Cogent Education	Examine the effect of a treatment package consisting of video and reflection, video feedback, and coaching on pre-service teachers’ use of nonverbal immediacy behaviors as they delivered lessons to student avatars in mixed reality simulations.	Immediacy theory	Mixed methods	Survey questionnaire or rating scale, observation, interviews	Teacher education	Physically	Video feedback and coaching fostered pre-service teacher reflection on the simulated environment as pre-service teachers delivered lessons within the simulation. Video feedback and coaching within a mixed reality simulation environment improved pre-service teachers’ use of nonverbal immediacy behaviors in student interactions.
13.	Piro & O’Callaghan, 2019	USA	Action in Teacher Education	Explore how threshold concepts as part of a practice-based teacher education program were experienced in mixed-reality simulations.	Liminal Learning	Qualitative	Observation	Teacher education	Physically	Learning within the mixed-reality simulations could be characterized by three spaces: preprofessional, liminal, and trending toward professional. The integration of mixed-reality simulations within initial teacher preparation core courses facilitated the journey of preservice teachers toward professional identities as they faced instructional and behavioral challenges.
14.	Cohen et al., 2020	USA	Educational Evaluation and Policy Analysis	Evaluates whether providing coaching between practice sessions in teacher education courses leads to more rapid development of skills and changes in teachers’ beliefs about student behavior, using mixed-reality simulations as a practice space and standardized assessment platform.	Practice-based teacher education (PBTE)	Quantitative	Survey questionnaire or rating scale, self-reflection	Teacher education and special education	Physically	Coached students had significant and large improvements in skills relative to those who only reflected on their teaching. Significant coaching effects were observed on students’ perceptions of student behavior and ideas of next steps for addressing perceived behavioral issues.
15.	Wernick et al., 2021	USA	International Journal of Mentoring and Coaching in Education	Investigates how debriefing conversations unfold during virtual coaching sessions that provide embedded opportunities to practice teaching within a mixed reality simulation (MRS).	Sociocultural theory	Qualitative	Observation, interviews	Teacher education	Online	The findings indicate that an MRS provides an immediate context for reflection, which guided the debriefing conversations. Functions occurred with varying frequency among pre-service teachers, PSTs and in-service teachers, ISTs, and across both groups, probing questions often led directly to reflecting and recapping the shared simulation context.
16.	Robbins et al., 2019	USA	Teaching and Learning Inquiry	Determine whether facilitating an immersive co-planning simulation would have an impact on targeted collaboration skills and whether vicarious observational learning would occur for students who observed the simulation.	Practice-based teacher education (PBTE)	Quantitative	Observation	Special education	Physically	The students did a better job of facilitating a co-planning session after having first practiced doing so via immersive simulation during a previous class session. It was also discovered that vicarious observational learning during immersive simulation positively affected performance.
17.	Luke et al., 2021	USA	Journal of Research on Technology in Education	Deepen our understanding of teacher candidates’ perceptions of their teaching performance during an online field experience using virtual simulation.	Practice-based teacher education (PBTE)	Mixed method	Survey questionnaire or rating scale, observation	Teacher education	Online	Teacher candidates did not accurately assess their instructional practices or the instructional practices of their peers when compared to the instructor’s assessment. Instructor and peer coaching were very beneficial. Teacher candidates and the instructor believed that online instruction was difficult, and perspectives on the authenticity of the online virtual simulation were ambiguous.
18.	Lew et al., 2020	USA	Information and Learning Sciences	Examine how pre-service teachers (PSTs) practice culturally and linguistically responsive teaching to work with an English learner (EL) avatar and other students’ avatars.	Culturally and linguistically responsive teaching and categorical thinking	Qualitative	Interviews, observation	Teacher education	Physically	PST participants made meaningful connections between theory and practices of culturally and linguistically responsive teaching. Nevertheless, they needed further improvement in incorporating cultural diversity into content lessons, creating a challenging and supportive classroom and developing interactional scaffolding for ELs’ language development. The findings also show that while PST participants perceived simulation technology as very beneficial, expanding the range of technological affordances could provide PSTs an opportunity to undertake a full range of critical teaching strategies for ELs.
19.	Bautista & Boone, 2015	USA	Journal of Science Teacher Education	Provide early childhood education (ECE) preservice teachers’ (PSTs) with opportunities to practice inquiry-based science teaching and to investigate the impact of TeachMETM Lab (TML) practices on ECE PSTs’ science teaching self-efficacy beliefs.	Social cognitive theory and Principles of Learning in Good Video Games	Mixed methods	Survey questionnaire or rating scale, self-reflection	Teacher education	Physically	Personal science teaching efficacy and science teaching outcome expectancy beliefs increased significantly after one semester of participation in TML. Three key factors impacted preservice teachers’ (PST) self-efficacy beliefs in the context of participation in TML: PSTs’ perceptions of their science content knowledge, their familiarity with TML technology and avatars, and being observed by peers. Overall, the results of this study suggest that the TML is a worthwhile technology for learning to teach in teacher education.
20.	Hudson et al., 2018	USA	Journal of Virtual Worlds Research	Explore the effects of mixed-reality teaching experiences, specifically on participants’ perceptions about their ability to manage student behaviors in a classroom setting.	Not explicitly stated	Mixed methods	Survey questionnaire or rating scale, interviews	Special education	Physically	Following the Mursion experiences, most participants perceived that: they were better prepared to teach, Mursion was an effective way to practice new skills, the avatars seemed like real students, they had more confidence to manage undesired behaviors, and they felt like they were in a real classroom. Mursion provides a safe environment for preservice teachers to learn complex skills such as classroom management.
21.	Kelley & Wenzel, 2018	USA	The Reading Professor	Explore elementary preservice teachers’ efficacy of conducting parent-teacher conferences centered on clearly and accurately sharing reading data and related interventions for a single case study student as part of a semester-long course assignment.	Not explicitly stated	Mixed methods	Survey questionnaire or rating scale, self-reflection	Teacher education	Physically	The pre-service teachers who conducted a parentteacher conference, 62% demonstrated the conference behaviors identified as non-negotiable from the onset of the Parent Teacher Conference project, meaning that they were not required to complete a second conference. Interestingly, however, 4% of the participating students voluntarily requested to have additional practice through a second simulation, though not required. This left 38% of the pre-service teachers who were required to set a conferencing behavior goal and complete a second parent-teacher conference simulation.
22.	Ledger & Fischetti, 2020	Australia	Australasian Journal of Educational Technology	Explore the benefits and challenges of Micro-teaching 2.0 and its impact on the self-efficacy of PSTs preparation for real life placements. It captures initial Micro-teaching 2.0 situated learning experiences and PST’s reflections on their practice.	Situated learning theory and reflective practice	Mixed methods	Survey questionnaire or rating scale, observation	Teacher education	Physically	The findings reveal increased self-efficacy of PSTs (n = 376) and identify the benefits and challenges of Micro-teaching 2.0 for initial teacher education programs. Micro-teaching 2.0 proved to be an effective diagnostic tool for identifying the specific needs of PSTs and a preparatory tool for real-life placements.
23.	Hayes et al., 2013	USA	Springer-Verlag	Explore efficacy and user experience of TLE TeachLivE™ to facilitate virtual rehearsal of pedagogical skills by teachers. Investigate a potential relationship between efficacy, in terms of knowledge acquisition and transfer, and user experience in regard to presence, suspension of disbelief, and immersion.	Not explicitly stated	Mixed methods	Survey questionnaire or rating scale, interviews, observation	Teacher education	Physically	The findings suggest that targeted practice, authentic scenarios, and suspension of disbelief in virtual learning environments may impact learning.
24.	Dalinger et al., 2020	USA	Computers and Education	Exploring candidates’ experiences with mixed reality simulations as part of their pre-service teacher education and investigated their perceptions of the simulation’s effects on their learning, confidence, and their subsequent live field experiences.	Constructivism	Qualitative	Interviews, observation	Teacher education	Physically	Participants considered the mixed reality simulation a more authentic form of practice than what their observations during field experiences afforded. Participants perceived transfer of learning from observations of peers during sessions with the mixed reality simulation to performance during their own sessions. Some participants perceived increased confidence in applying skills practiced during the simulation to work with live students and parents. Using the mixed reality simulation posed challenges including suspension of disbelief, meeting candidates’ needs, and the presence of a peer audience.
25.	Driver & Murphy, 2018	USA	Journal of Technology and Teacher Education	Explore the influence of embedding a sequence of mixed reality simulations into a course on collaboration for special educators, and study preservice teachers’ ability to communicate effectively in collaborative partnerships.	Practice-based teacher education (PBTE)	Mixed methods	Survey questionnaire or rating scale, focus group discussion, observation	Special education	Physically	There were significant shifts in preservice teacher perceptions of their readiness to work in collaborative settings from the beginning to the end of the study, as well as improvement in communication skills.
26.	Gul & Pecore, 2020	USA	Journal of Technology and Teacher Education	Examine the impact of stress, strategies for coping with stress, and professional identity development of pre-service teachers when teaching to avatars.	The stress appraisal theory	Qualitative	Interviews, observation, self-reflection	Teacher education	Physically	The results highlight that while positive stress increases productivity, creativity, and motivation, negative stress causes a lack of confidence, self-efficacy, and motivation, thus negatively affecting professional teacher identity development.

, Appendix A.

3. Results

The articles included were published between 2013 and 2021. Virtual simulations in teacher education are thus a new research area and there has been a large increase in articles in recent years. Of the 26 articles, 17 were published between 2019 and 2021. Almost all studies were conducted in the US. Only 2 out of the 26 articles had been conducted in Australia. The geographical range is thus very narrow.

A total of 22 academic journals were represented. Four journals had published more than one article in the field, namely Teacher Education and Special Education, Education Sciences, Action in Teacher Education, and Journal of Technology and Teacher Education.

In total, 11 studies used mixed methods, 10 used quantitative data, and 5 used qualitative data. The most common measures in the studies included were survey questionnaires or rating scales (17), and observations (15). The least commonly used methods of data collection were self-reflection (8), interviews (8), and focus-groups (3). Research on virtual simulations was mostly carried out in teacher education contexts (15), but some also focused on special education (6). Some studies examined virtual simulations in both teacher and special education (5). Virtual simulations can be performed both offline on campus and completely online. Most research on virtual simulations has taken place almost exclusively on campus (23), though studies have also begun to explore the use of virtual simulations online (3).

The studies relied on a large variety of different theories. One reason for the breadth in theories may be that the simulations were used in different fields of research. For example, two studies examined self-efficacy and used theories related to this construct. In the studies included in this review, the theories used encompass social cognitive theory, situated learning, the action review cycle, immediacy theory, liminal learning, sociocultural theory, constructivism, and the stress appraisal theory. PBTE appeared in four studies.

3.1. Different Teacher Competences That Virtual Simulations Have Intended to Practice

In the included studies, a wide range of skills have been investigated with the support of virtual simulations, for example:

• Improving teaching skills [21,22];
• Instructional challenges [23,24];
• Managing behavioral challenges [21,24,25,26];
• Classroom management strategies [26,27,28,29,30];
• Collaboration skills [22,31,32];
• Giving and receiving feedback [22,33];
• Conferencing skills [34];
• Managing stress [35];
• Communication skills [36].

The skills examined are quite similar regardless of whether virtual simulations are used only in teacher education, in both teacher education and special education, or only in special education. A difference that exists is that when virtual simulations are used in special education, disabilities often are included, for example by the avatars exhibiting various forms of disabilities [28,31,37].

In relation to the categorization suggested by Nordenbo, Larsen, Wendt, and Østergaard [16], the competence that is almost exclusively investigated with the support of virtual simulations is rule management competence. As mentioned above, the studies included examined improving teaching skills, instructional challenges, managing behavioral challenges, classroom management strategies, collaboration skills, and giving and receiving feedback. All of these skills are included in the rule management competence category, because they, in some way, focus on the teacher’s leadership. In total, 22 of the 26 studies are included in this category.

Didactic competence is investigated in three of the studies included. One study describes a parent teacher conferencing project that aimed to provide elementary pre-service teachers the opportunity to develop their reading assessment conferencing skills in a virtual environment. Pre-service teachers practiced responding to parents’ common questions or concerns related to their child’s reading development [34]. In another study, early childhood education majors had the opportunity to practice inquiry-based science teaching. The study aimed to investigate the impact of virtual simulations on early childhood education majors’ science teaching self-efficacy beliefs [38]. The third study focused on teachers’ readiness to use and develop a specific reading strategy [39].

Relational competence is investigated in one of the studies included. Driver, Zimmer, and Murphy [36] explored virtual simulations in a course on collaboration for special educators. The researchers study preservice teachers’ ability to communicate effectively in collaborative partnerships. The pre-service teachers practiced for example effective communication, interpersonal skills, and respectful manner.

The categorization of the 26 included articles thus shows that 22 articles investigate some kind of rule management competence, 3 articles investigate didactic competence, and 1 article investigates relational competence.

3.2. Preservice Teachers’ Experiences of Virtual Simulations

Research on preservice teachers’ experience of virtual simulations gives an overall positive picture [26,28,32,37,39,40]. The preservice teachers describe simulations as enjoyable and as building confidence in teaching [39]. They also describe simulations as more useful than textbooks [37], and significantly more useful than role-play [32]. In addition, the preservice teachers valued the opportunity to practice classroom management skills in a consequence-free environment with avatars instead of real students [26,28,39]. Another reason that the preservice teachers experienced the simulations as positive was that they served as self-assessment tools for assessment of their teaching skills. The preservice teachers were aware that simulations are not targeting a specific behavior or strategy, but a tool where they can practice and try out a variety of strategies [40].

When it comes to authenticity, preservice teachers have different experiences of virtual simulations, although most preservice teachers describe simulations as realistic [21,32,37,39]. The preservice teachers who experienced authenticity emphasized interactivity as a contributing factor. They experienced that the high level of interactivity provides a sense of interacting with real students, and the avatars felt highly expressive, responsive, and engaged. This made the preservice teachers forget the screen and the fact that they interacted with avatars. Despite the avatars’ inability to change their facial expressions, the preservice teachers perceived that they could pick up avatars’ emotions, for example, hesitance, confidence, willingness, relief, and excitement. The avatars showed these emotions through their frequency of participation, voice volume, hand gestures, nodding, and shying away [40].

However, there was also research where the preservice teachers’ perceptions of authenticity were ambiguous. Some preservice teachers felt that the simulation lacked the authenticity of real classrooms, while others felt as if the avatars were real children. There were also different experiences depending on whether the preservice teachers observed or taught the avatars. The preservice teachers perceived the simulation as more realistic when they observed the avatars, as compared to when they taught them [23].

During the first simulation session, preservice teachers are often anxious or nervous [26,28,39]. They were nervous because the simulation context was new and some of them felt pressure to perform well [39]. The preservice teachers also experienced technological limitations, for example, the avatars’ inability to physically move and do hands-on activities [40]. Because the avatars had limited mobility (they could not move out of their chairs), a frequently used classroom management technique (i.e., proximity) became difficult to demonstrate. Some also felt that sound and technical difficulties were distracting [26].

3.3. Identified Advantages and Disadvantages of Virtual Simulations

The results from the studies included show several important advantages with virtual simulations. For example, simulations may help improve preservice teachers’ knowledge, skills, and approaches to teaching. In the included studies, practice through simulations is described as a promising tool in learning basic aspects of teaching [21,30]. The preservice teachers develop their ability to manage a classroom [28] and gain confidence in their abilities [22]. The coaching in the simulations contributes toward developing the preservice teachers’ skills [23,41], and has effects on their perceptions of behavioral problems [25].

A common topic of research on virtual simulations is classroom management. Studies in this area show that simulations improve teaching skills and preservice teachers’ readiness to manage a classroom and teaching performance [21,22,23,25,28,30,41]. Collaboration with colleagues is another area of research where virtual simulations have been used. These studies focus on how debriefing conversations unfold during virtual coaching sessions and whether a co-planning simulation has an impact on collaboration skills [31,42]. Also in this area, the advantages of simulations are presented by showing that the preservice teachers improved the co-planning sessions, in which they participated after practicing in the simulator [31]. Even when it comes to preservice teachers’ sense of self-efficacy, the studies showed that virtual simulations were advantageous to improve their self-efficacy after participating in simulations [33,43].

Despite descriptions of the numerous advantages of virtual simulations, some disadvantages emerge in the studies. The disadvantages that are described in the studies are almost exclusively caused by technical limitations [26,37,40]. For example, avatars cannot move out of their chairs, which is a limitation regarding preservice teachers’ manifestation of teaching techniques, such as “proximity” [26], and the avatars’ inability to physically move and take part in hands-on activities may restrict the preservice teachers from practicing all aspects of teaching strategies [40].

4. Discussion

The aim of this review was to search for and analyze studies on the use of human- and computer-based virtual simulations in teacher education, including special education, in order to better understand how the use of such simulations may support the development of preservice teachers, as well as to identify gaps in the literature and suggests potential routes for future research.

In the articles included, a wide range of skills have been investigated with the support of virtual “human-in-the-loop” simulations. It was found that such virtual simulations are a promising tool that may contribute to improving general teaching skills, such as managing behavioral challenges, and applying classroom management strategies [21,22,23,24,25,26,28,30]. At first, there may seem to be evidence for the successful implementation of virtual “human-in-the-loop” simulations in teacher and special education. However, research has almost exclusively been performed in the context of North America and this may affect the generalizability of the positive effects of simulations to contexts outside the United States. Results must be seen in light of the fact that educational contexts differ in different countries. For example, in the U.S., special educator programs are basic programs (i.e., students are admitted to either teacher education or special education), but in other countries, they may be offered as a supplementary education for teachers at an advanced level. The findings of previous research may be transferable to some extent, but it is important to interpret the results with some caution, since they might be overly optimistic in some cases and less so in others, for instance depending on differences in experience among the pre-service teachers involved. Since the results reported suggest that virtual “human-in-the-loop” simulations could play an important part in teacher education, it would be interesting to carry out studies in other educational contexts as well.

It is also interesting to note that, with the exception of geographic range, the research about virtual “human-in-the-loop” simulations is very heterogenic. Studies in this area use different methods, different terminology, and different theory, making the findings difficult to compare and also to paint an overall picture of the research. Consequently, there is an urgent need for researchers in this area to communicate with each other, in order to create a common understanding of the merits and limitations of virtual “human-in-the-loop” simulations, and to develop the methodology further.

The first research question that guided this review was about the different teacher competences that virtual “human-in-the-loop” simulations have intended to practice. Teacher competence may be subdivided into rule management competence, didactic competence, and relational competence [16]. The studies included almost exclusively examined rule management competence. There were three studies that investigated the development of didactic competence and, like rule management, these showed promising results [34,38,39]. One study explored relational competence and focused on effective communication, interpersonal skills, and respectful manners. This competence was also highlighted as positive to practice with the support of virtual “human-in-the-loop” simulations [36].

Virtual “human-in-the-loop” simulations thus show promising results when it comes to developing all three aspects of teacher competence. However, since the studies reviewed almost exclusively focus on rule management competence, it is difficult to draw any conclusions about using simulations to support didactic and relational competences. It would therefore be interesting for future research to investigate didactic and relational competences with the support of virtual “human-in-the-loop” simulations. Previous research highlights that an important advantage of such simulations is that they provide the opportunity for pre-service teachers to practice in controlled and safe environments without the risk of harming students [3,4,5]. This is an important ethical argument for implementing virtual simulations in teacher education, and particularly in special education. From an ethical perspective, virtual simulations have an important function to fulfill by giving teachers the opportunity to practice situations that are especially problematic in relation to vulnerable students, such as students in need of additional support, who risk being harmed by inappropriate actions. Future research should, therefore, seek to investigate whether and how virtual “human-in-the-loop” simulations are suitable for the development of didactic and relational competence, both in general and specifically in relation to students who experience some form of learning difficulties, such as neuropsychiatric difficulties.

The second research question for this review addressed preservice teachers’ experiences of virtual “human-in-the-loop” simulations. It was found that their experiences were mostly positive [26,28,32,37,39,40]. Something that is important to consider, however, is the perception of authenticity, as this is fundamental for interacting with the avatars in a realistic manner. Although preservice teachers in most cases seem to be immersed in the simulation, forgetting that they are not interacting with other humans, more ambiguous findings are also reported. More research is therefore needed to understand what makes the difference.

Another theme in the research is that the preservice teachers can become anxious or nervous when asked to teach in a simulation environment [26,28,39], which may affect their performance. Teacher educators therefore need to be aware of this and act to prevent it as much as possible, for instance through information about what is expected and to listen to and respect the preservice teachers’ feelings. If not, the validity of conclusions based on preservice teachers’ performance during the simulation may be questioned. This also points to an important route for future research, where preservice teachers’ teaching competence as manifested in a simulation context is compared to authentic classroom settings. Future research needs to establish whether the improvements in teaching skills documented during simulation events inform and influence pedagogical practice in other settings as well.

The third research question that guided this review was to identify advantages and disadvantages of virtual “human-in-the-loop” simulations. The results show great advantages with such simulations when it comes to learning basic aspects of teaching [21,30]. The disadvantages reported are, as noted in relation to previous reviews on virtual “human-in-the-loop” simulations, almost exclusively attributed to technical limitations [26,37,40]. The advantages are thus educational, while the disadvantages are mainly seen as technical. However, technical limitations can have pedagogical implications. According to Lew, Gul, and Pecore [40], the avatars’ inability to physically move and take part in hands-on activities restricts the preservice teachers, preventing them from practicing all aspects of teaching. Therefore, it is important for teacher educators to have an understanding of the technical possibilities and limitations with virtual “human-in-the-loop” simulations in relation to the competences that are intended to be practiced, otherwise there is a risk that technical limitations are misinterpreted as preservice teachers’ pedagogical shortcomings of the preservice teachers. This also points to the importance of understanding the advantages and limitations of virtual simulations more broadly, so that the methodology is used adequately. In this review, a coarse categorization of different teacher competences has been made, but it is imperative for future research to extend this ambition by detailing more closely which aspects of teachers’ work that may be validly practiced in such an environment, and which may not. This calls for a closer connection between research on virtual simulations and nuanced theoretical frameworks of teacher competence.

Limitations and Areas for Future Research

The systematic research review is based on a clear and strict methodology [18], but its strict systematics can also be seen as limiting. Therefore, the studies included have been added both through systematic database searches and snowball searching to increase the rigor and quality of the systematic review. There has been some flexibility in the analysis, by introducing the categorization of teacher competence by [16], which was not specified by the methodology.

In conclusion, virtual “human-in-the-loop” simulations are a new area of research that shows promising results. However, as has been shown by this and previous reviews, there are still many questions left unanswered. In particular, this review suggests that more research is needed in a number of different areas:

• Today, the geographic range of the research is very narrow, consisting almost entirely of research from the US, making generalizations difficult. Research from other countries is therefore needed, especially since teacher education programs differ across countries.
• Apart from geographic range, the research is heterogenic in most other aspects, making comparisons across studies difficult. Research in this area would therefore need a common ground, so that it would be possible to identify merits and limitations in a more coherent way and to develop the methodology further.
• Although there is a range of different teaching constructs represented in the studies reviewed, most of them belong to the “Rule management competence”. It would therefore be interesting to include other aspects of teacher competence, in order to find the effective range of different competences that can be validly practiced in a simulation context, but also to more closely map the pedagogical limitations. Findings from this review also point to the importance of linking the positive findings from simulation events to authentic classroom practice.
• One of the main arguments for using simulations is that it enables preservice teachers to practice in a controlled and safe environment without the risk of harming students. This is most imperative in relation to vulnerable students, such as students in need of additional support, which means that more research on virtual simulations is needed in special education programs.
• The perception of authenticity among preservice teachers is fundamental for interacting with the avatars in a realistic manner. More research is needed to understand why some are immersed in the simulation, while others are not.