Learning-centered lesson design and learning about teaching in a pre-service teacher education course

Abstract Designing lessons is a prominent means in pre-service teacher education for developing student teachers’ understanding of what good teaching involves and how to plan for such teaching. A new approach to teaching lesson design in a pre-service teacher education program has prompted research on what and how student teachers learn from this new approach to prepare them for teaching. This article reports on practitioner research that draws on principles derived from the body of scholarship dubbed the “science of learning”. An interpretive research approach was followed, and data was collected via semi-structured interviews that were juxtaposed with lessons that student teachers designed. The pattern that emerged from the analyzed data was that this new lesson design approach helped student teachers to develop a good understanding of the nature of learning; and that such understanding is important because teaching is ultimately about helping learners to learn. In addition, participants articulated that invoking the principles used forced them to be more metacognitive and intentional in designing the lessons. Thus, moving beyond teaching methods and classroom discipline to a focus on how to best guide and support the intended learning of specific learners. Participants were also of the view that the approach is suitable to use in varying contexts because it is not dependent on the availability of resources. The authors conclude that a lesson design approach that draws on the science of learning has much to offer student teachers towards becoming adaptive experts who are able to create significant learning experiences for learners. Additionally, pre-service teachers will benefit from an approach that is modelled by teacher educators, and which employs an iterative process that uses deliberate practice to work towards adaptive expertise.


Introduction and background
Teaching pre-service teachers how to plan/design lessons is considered an essential component of pre-service teacher education. Despite this, there is no consensus regarding how best to prepare student teachers for lesson planning. Nevertheless, a linear model of lesson planning has been widely used (Cameron & Campbell, 2013). This model generally employs a lesson planning template that requires student teachers to address the following elements: the lesson topic and learning content; the aims/objectives of the lesson; the specific learner profile; the teaching and learning activities to be used; and the assessment/evaluation activities in relation to the aims and objectives of the lesson. Although such a model captures the basic elements to be taken into consideration when teaching, it does not require student teachers to make their thinking processes (in relation to planning for teaching) explicit. Recognizing the limitations of using a template-driven linear model of lesson design/planning prompted some pre-service teacher education programs to adopt approaches that require student teachers to explicitly put into practice what they have learned in their coursework-thus bringing "theory and practice" together (Contreras et al., 2020, p. 2) in relation to which teaching strategies to use and why (Cameron & Campbell, 2013;Li & Zou, 2017;Sural, 2019). The underlying argument is that lesson planning/design should allow student teachers to reflect on their design decisions (Fernandez, 2010;Maynes & Julien-Schultz, 2011) which could be key to student teachers' learning about how to teach effectively (John, 2006).
At the University of Johannesburg, we grapple continuously with how best to prepare student teachers for a lifelong career in education. One approach, which has guided the four-year Bachelor of Education (BEd) programme for primary school teacher education since its inception, is a central organizing principle rooted in child study (Gravett et al., 2014(Gravett et al., , 2019 or pedagogical learner knowledge (Darling-Hammond, 2006). We have argued that studying children and their development, both during coursework and in school classrooms over the four-year program can contribute to providing student teachers with a solid basis of how to teach in ways that are accommodative of children's developmental needs.
In addition, we have argued that lesson design is a prominent means in pre-service teacher education to develop student teachers' understanding of what good teaching involves and how to plan for such teaching. Although the student teachers encounter lesson planning/design to some extent from their first year of study, we were not convinced that the approach used adequately equipped them to teach in the varying contexts of schools, currently and in the future, taking the rapidly changing world into account and the implications of constant change for education. To us, this necessitated that lesson design should contribute to laying a basis for the development of adaptive expertise in student teachers. The question was how to approach lesson design to achieve this outcome.
The body of scholarship, referred to as the science of learning presented a way forward. Darling-Hammond et al. (2019) noted that the rapid advances in "knowledge regarding human development and learning" (i.e., the science of learning), has concurrently "increased the opportunity to shape more effective educational practices" (p. 98). This prompted us to move towards developing a new approach to lesson design that draws explicitly on the science of learning. The envisaged approach was workshopped with a group of teacher educators and research collaborators prior to its implementation in 2020 with final year BEd student teachers.
Despite having undertaken a thorough literature search, we could not locate research on lesson design that had an explicit science-of-learning underpinning. For this reason, and to understand the potential affordances of the approach, the first iteration of the new approach was researched in 2020, and a second (slightly adapted) iteration was implemented and researched in 2021. This article reports on one aspect of the research, namely, what and how student teachers learnt from an approach to lesson design that draws on principles derived from the science of learning. We dubbed the approach learning-centered lesson design. The question that guided the research was, "What and how did student teachers learn from implementing a lesson design approach that draws on principles derived from the science of learning?". The next section briefly explores the literature that framed the lesson design approach, and which was also used to frame the research. This is followed by a description of the research methods. Lastly, the findings are presented and discussed.

Framing the lesson design approach and the research
The learning-centered lesson design approach was framed by three interrelated educational convictions, namely: that lesson design that requires student teachers to explain the rationale for their planning decisions could assist pre-service teachers to develop the beginnings of adaptive expertise; that deliberate practice is important for supporting the development of teachers as adaptive experts; and that, because teaching is first and foremost about enabling learning, the development of adaptive expertise should be interlinked with a thorough understanding of the nature of learning and the learning process.

The science of learning and lesson design
The core point of departure for this new approach is that teaching is primarily about enabling learning. Thus, good teaching presupposes a thorough understanding of the nature of learning and the learning process.
The new learning-centered approach requires student teachers to connect teaching practices outlined in the lesson plan to core ideas (principles) derived from the science of learning literature. Thus, student teachers had to explain the rationale for using specific teaching practices and techniques by drawing on these principles. To enable student teachers to do this, a comprehensive document, supplemented with prescribed readings, was developed. The document (Gravett, 2020) combined insights from cognitive psychology, developmental psychology, and cognitive neuroscience into the learning process and, by implication, how to teach to guide and support the learning of others. Our approach (and the document) drew, among others, on:  (2000); National Academies of Sciences, Engineering, and Medicine (2018); Willingham (2009Willingham ( , 2021; and Wilson and Conyers (2020). The document was refined and extended in 2021, although the essence remained the same. The principles, drawn from the science of learning literature and accompanied by possible classroom implications and teaching practices, were: We understand and learn new ideas by relating them to what we already know; learning requires attention and cognitive engagement; learning involves our working-memory and long-term memory; cognition and emotion are intertwined; having learned something does not imply that transfer will happen automatically; and that learners learn more effectively if they engage metacognitively. Although not stated as a principle that should inform lesson design, the student teachers were also introduced to the notion of neuroplasticity (Ansari et al., 2017) and its implications for teaching. Additionally, it was made clear that the principles are interrelated.
Although it was expected that student teachers draw on the principles when designing lessons, it was emphasized that, due to the complexity of teaching, the science of learning does not provide fool-proof recipes for teaching. What we were aiming for was to assist student teachers to connect their understanding of human learning with teaching decisions and practices. We wanted to guide them on how to make teaching decisions based on articulated principles derived from the science of learning. We concur that if teaching is guided by a core set of learning principles, then the selection of teaching strategies (mediated, of course, by subject matter, grade level, and desired outcome) can be purposeful. The many possibilities then become a rich set of opportunities from which a teacher constructs an instructional program rather than a chaos of competing alternatives. Focusing on how people learn also will help teachers move beyond either-or dichotomies that have plagued the field of education (National Research Council, 2000, p. 23).
We contend, for example, that the dichotomy of learner-centeredness vs teacher-centeredness that is often put forward in education literature is not helpful. Although the intent of advocating learner-centeredness in teaching may not be to underplay the role of the teacher as pedagogical guide, it opens the door to such an interpretation and, by implication, that discovery learning should always be favored. Obviously, teaching should be geared towards the learners, but that does not dictate specific pedagogical approaches. We argue that teachers should choose and use teaching practices and techniques thoughtfully based on the full context, including the background knowledge and the life-worlds of learners and the complexity of the learning content, and, we would add, their solid understanding of the nature of learning. We therefore position teaching, and lesson design, as learning-focused/centered -implying that the role of the teacher is to create significant learning experiences (Fink, 2013) for learners. This means that teachers should create learning experiences for optimizing meaningful learning, which is a prerequisite for the longevity of learning. "Significant learning is durable, relevant learning, because it either forms an important basis for future learning or it is of value for learners' current lives or the lives that they are likely to live" (Gravett, 2022, p.2). It is, therefore, transferable learning in that it can be used or applied beyond the immediate situation. This type of learning is also referred to as deeper or meaningful learning (Pellegrino, 2017).

Developing the beginnings of adaptive expertise
We do not dispute the importance of pre-service teachers acquiring routine expertise, which involves the competency to apply teaching practices and routines and solve familiar types of (teaching) problems fluently and efficiently (Anthony et al., 2015), but we agree with Hammerness et al. (2005) that developing adaptive expertise is an "appropriate gold standard" (p. 360) to pursue in teacher education.
Metacognitive monitoring is an important component of adaptive expertise (National Research Council, 2000). Teachers with adaptive expertise have developed metacognitive awareness that prompts them to continually self-assess their performances and modify their assumptions and actions as needed. They metacognitively monitor why, and under which conditions, certain approaches are appropriate to be used; or why and when new approaches need to be devised (Anthony et al., 2015). Teachers with adaptive expertise are thus flexible and can rethink their ideas and practices to change what they are doing (Van Tartwijk et al., 2017) when the situation demands it, or when they must deal with novel situations and problems (Carbonell et al., 2014). This is crucial for teachers because every teaching context requires a teacher to assess whether the chosen teaching approach and practices are suitable to help the learners to learn. Teaching is never routine (Hammerness et al., 2005). Recently, the COVID-19 pandemic underlined the importance of adaptive expertise for teaching as teachers had to adapt their ways of teaching and innovate almost overnight. This underscores the need for pre-service teacher education to prepare student teachers for unpredictability, in as far as this is possible. We are of the view that an intentional focus on developing adaptive expertise presents a promising way to do this, even though we recognize that the development of adaptive expertise cannot be accomplished within the timeframe of a teacher-preparation programme. However, teacher preparation programs that pay methodical attention to the development of adaptive expertise could provide a solid basis for extending adaptive expertise over time.

Deliberate practice
Deliberate practice is viewed as a means of developing adaptive expertise in teacher education (Anthony et al., 2015;Carbonell et al., 2014;Darling-Hammond et al., 2019). The essence of deliberate practice is engaging in goal-directed practice to improve current levels of performance (Bronkhorst et al.,). This should happen in a safe learning environment that allows for gradual refinement through rehearsing, accompanied by feedback, analysis and reflection.
The five principles of deliberate practice put forward by Deans for Impact (2016) are useful for guiding the implementation of deliberate practice in teacher education. These are: pushing student teachers beyond their comfort zones; working towards well-specified goals; focusing intently on practice activities; receiving and responding to high-quality feedback; and developing a mental model of expertise. Figure 1 depicts the lesson design approach and its framing.

Research methods
The research can be broadly typified as practitioner research because both authors were involved in designing the lesson design approach that was the focus of the study. The second author also presented the course on lesson design and collected the data.
As is the case with other types of research, the aim of practitioner research is to generate (new) knowledge. However, practitioner researchers differ from other researchers because of their positioning in the research process. A practitioner researcher is someone who is employed in  a professional capacity and who, as part of their role, undertakes research related to their role (Fox et al., 2007). We conducted practitioner research by systematically collecting data about what and how student teachers learnt from the lesson design approach with the aim of contributing to teacher education knowledge about lesson design which invokes principles derived from the science of learning and how such a lesson design approach could prepare student teachers for teaching.
We were also, by implication, interested in their views on the value of what they learnt. To this end, an interpretive research approach was followed which rests on the assumption that there are multiple ways in which reality can be perceived or experienced. Based on the participants' realities/ experiences, research evidence is co-generated between the researcher and the researched (Schwartz-Shea & Yanow, 2012).
To generate data, semi-structured interviews were conducted with 15 student teachers from the 2020 student cohort (N = 183) and 12 from the 2021 cohort (N = 197). The participating student teachers were chosen at random using the list of students enrolled for the course. Using semistructured interviews is typical in interpretive studies where the focus is to "encounter, or be exposed to, the wide variety of meanings made by researcher-relevant participants of their experiences" (Schwartz-Shea & Yanow, 2012, p. 85). The semi-structured interviews were conducted after the conclusion of the academic year in 2020 and 2021. Table 1 shows the primary interview questions asked during the interviews.
The Faculty of Education Ethics Committee provided ethics clearance for the research (ethics clearance number: 2-2020-091). Participants gave written informed consent in accordance with the Declaration of Helsinki.
As previously noted, the second author was involved in presenting the course and collecting the data. At the time when the course was implemented, the second author had a good relationship with the student teachers who were enrolled in the course because he had taught them in their previous years of study. Because of this, we were mindful that the student teachers may be tempted in the interviews to mention only their positive experiences or learnings in the course while choosing to remain silent about gaps in their understanding or negative experiences. Thus, due to the second author's positionality as course presenter in the research, sense-making during data generation and analysis (Schwartz-Shea & Yanow, 2012) was deliberately checked. The first author's role in this regard was to act as a sounding board and ask critical questions.

Primary interview questions (semi-structured interviews).
• Tell me about your experience of the methodology course this year.
• What have you learnt about teaching this year that you had not learnt before, if anything? How will this influence your practice as a teacher?
• What have you learnt about the learning process this year that you had not learnt before, if anything? How will this influence your practice as a teacher?
• The lesson design process that you were taught this year differs from what you did in previous years. How would you describe the difference?
• What (if anything) have you found valuable in relation to the new lesson design process?
• What difficulties (if any) have you experienced with the new lesson design process?
• Has the new lesson design approach influenced your view of teaching? If so-how? And why?
In addition, to work towards credibility of the findings, triangulation of data sources was used "to compare and cross-check the consistency of information derived" (Patton, 2015, pp. 661-662). The interview data was tested against the lessons that students designed. None of the categories derived from the interview data were contradicted by the lessons that students designed. In fact, the lessons corroborated the findings.
Data were analysed using the constant comparative method of analysis (Maykut & Morehouse, 1994;Merriam & Tisdell, 2016) which commenced with reading each transcript of the interviews thoroughly to identify provisional categories. After provisional categories were identified, the transcripts were coded by identifying individual "units of meaning" (Maykut & Morehouse, 1994, p. 128) and assigning a code that contained the essence of the unit of meaning. Using "look/feelalike" criteria described by Maykut and Morehouse (1994, p. 137), similar units of meaning were sorted into the same provisionally identified categories. Where there were no provisionally identified categories that matched the semantic units of meaning, new categories were developed. This resulted in some initial categories merging and some being discarded. Categories were continuously refined by writing rules of inclusion, which served as the basis for including or excluding codes in the identified categories.
Further refinement happened by comparing and contrasting the categories derived from the analysis of the 2020 data with the 2021 data. Figure 2 summarises the data analysis process that was followed.
The final categories serve as the findings of the study. These are presented below.

Presentation of findings
The data analysis process generated four categories that encapsulate what and how student teachers learnt. The categories serve as answers to the research question, which was about what and how student teachers learnt from a lesson design approach that draws on principles derived from the science of learning. Thus, the categories serve as the findings of the study. The provided excerpts from the interviews illustrate the categories.

Category 1: Student teachers developed a solid understanding of the nature of learning and the learning process and why such an understanding is important
Student teacher 4 (2020) said: "Now I understand how learners learn. I understand what I feel needs to go into a specific lesson plan, and which principles to touch on in order to basically reach their objectives and aims that are mentioned in the lesson". Student teacher 7 (2021), when talking about the principles, said: "They help you understand also how children manage their learning". Student teacher 9 (2021) said that if teachers knew this way of lesson design " . . . through all these diverse contexts where children are learning, I think teachers would start seeing education . . . as one thing that's meant for learners, they will start identifying themselves as people who are there to help the learners learn, rather than just being there to teach".
Many student teachers used specific examples derived from their knowledge of the principles they had to use to design lessons to explain how learning happens and how to guide and support learning. The following excerpts from the interviews exemplify this: I think if a teacher creates a positive environment where kids can answer questions, ask questions, learners will be better able to learn the content in more depth, because if they are too scared, they won't want to raise their hands and they get nervous and they won't want to tell you the answer because now you are just going to shout at them. So, I feel like beside the cognitive aspects, the environmental aspects are really important and it really influences how children learn, well how effective their learning is (Student teacher 2, 2020). I learned how important questioning is during lessons and I learned how they contribute to your lesson. You know getting learners engaged and so forth, and you know you need to have different levels of questioning and you need to be precise in your questioning (Student teacher 6, 2021). I can't just start the lesson without knowing what they already know. I can't just like you know, like I said before, give them too much information. So, as a teacher I think it will help me manage my teaching, making sure it's effective and the learners are also learning (Student teacher 7, 2021).
I've learned that for questioning to be effective it must be purposeful. You must ask learners open ended questions where they . . . where you are able to see their reasoning and their thinking (Student teacher 9, 2021).
The above excerpts show that the student teachers developed a sound understanding of the nature of learning and the learning process and why such an understanding is important. Of note is the view, expressed implicitly and explicitly, that teachers should understand their role as helping learners to learn, rather than just teaching (implying not paying deliberate attention to the learning of learners). There is thus evidence that student teachers understood the importance of what we refer to as learning-centeredness in lesson design. The examples that student teachers used also serve as evidence of the understanding that they developed of how to guide and support learning, using the principles derived from the science of learning literature.

Category 2: Student teachers learned that designing lessons that invoke principles derived from the science of learning literature requires deep thinking about how to best support learning
The data points to the fact that the student teachers learnt that infusing the science of learning principles in lessons requires thoughtfulness in design. Student teachers explained that thinking carefully about how and why to infuse the science of learning principles in the lessons they designed helped them make sense of how to design lessons that foreground learning.
The following excerpts from the interviews are indicative of this finding: We have to think about how we can best apply these principles for learning to take place (Student teacher 1, 2020).
What I really enjoyed were the learning principles that were taught . . . So, the reason why I say I enjoyed it was because now when I plan my lessons, I don't just plan my lessons for the sake of planning, "oh I have this topic so I must just quickly do this and move past it". It actually makes me think about what I want to deliver at the end of the lesson. What do I want the learners to take out from the lesson (Student teacher 5, 2020).
The learning principles gave me a lot to think about in terms of teaching that I was not aware of. So, you know like most of the time we would think about teaching in terms of the methods that we use and classroom discipline and all of that, but we have actually not thought about the actual learning, you know of the learner. You know when actual learning takes place (Student teacher 9, 2020).

Category 3: Student teachers are of the view that knowledge of how learning happens will serve them well in varying school contexts
Exploring what and how student teachers learnt from the lesson design approach also meant that we were interested in their views on the value of what they learnt. The data showed that the student teachers viewed what they learnt about learning-centered lesson design as potentially serving them well in varying contexts. This finding is exemplified in the following excerpts from the data: I think it would make my lessons more meaningful, because knowledge of these principles, . . . like I know what is needed when creating an appropriate lesson plan, so my lessons would be more meaningful no matter the context because it can be adapted to any context (Student teacher 1, 2021).
No matter where you are, no matter what resources you have, if you think about why you are going to be doing something and how that's going to affect your learners, then you can actually try and think about the resources you have and how you're actually going to use them to . . . to actually bring about positive learning experiences for your learners (Student teacher 9, 2021).
If I would teach in any school context, with my knowledge of the new lesson design, I think . . . even with less resources, with the knowledge that I have now . . . how I would structure their lessons to accommodate their small working memory and . . . and all those things, I think in my teaching I would always have those at the back of my mind (Student teacher 10, 2021).

Category 4: Designing a lesson in iterations coupled with feedback and practice deepened student teachers' understanding of lesson design that aims to place student learning central
The data analysis showed that the student teachers viewed the iterative approach to lesson design, coupled with the feedback they received on their designed lessons, as helpful. Though the iterative process was used in 2020, it was strengthened in 2021 due to its success, which was evident in 2020. The iterative process followed is explained in the discussion session in relation to deliberate practice. For now-it is clear from the excerpts below that the iterative process followed induced reflection and contributed to a deepened understanding of the lesson design approach and its benefits.
You reflect on the whole thing, from start to finish. What worked, what didn't work. . . And with that, you can go back and say. . . Ok, if I teach this next time, this is how I am going to change it. These are the principles that I am going to change. These are the principles that I'm going to use. And I feel that as a student teacher, that actually helps one with selfreflection (Student teacher 4, 2020).
My first iteration, my lesson plan was so short, so basic it's kind of like I just assumed that whoever is going to read it would just understand what I mean. So, she [the teacher educator] taught me how to make it very, very detailed but not long just detailed in a summary form if that makes sense, and how to be meaningful . . . As I progressed and got to the third and fourth iteration, well mostly the fourth iteration it's kind of like a light bulb went on and got to see like 'this is what I need to do (Student teacher 1, 2021).
So, we started off with our introduction, we had to get evaluated on that and then the next one . . . your introduction and your body and then get evaluated on that. So, I think also that gave us enough time to, you know brainstorm the different phases of a lesson and actually understand what we're doing in relation to like putting the principles into it (Student teacher 3, 2021).
With our last submission, you now just see how your entire lesson plan came together and when you look back, because I actually reflected back on my first cycle, my lesson design to my fourth one, and I could see the improvements on how I was able to infuse those principles in ways that I never really knew in the beginning of the year (Student teacher 6, 2021).
The iterative lesson design process involved practice and reflection sessions. The data highlighted the importance of these sessions to help student teachers to make increasingly deeper sense of the lesson design approach.
You do a portion, you try it, you make use of these principles and sometimes you think you do understand it, but not entirely and then when you submit the iterative task it comes back with the feedback to say 'Okay, but you should have done this, this doesn't make sense you know'. Also prior to each and every session, the lecturer would say 'okay if you want us to go through your lesson, you can send it through and then we will try to go through it together you know', and then as we are going through it together, that portion we are able to make corrections here and there and make suggestions and question where you did things as a student so I think it really did help you know (Student teacher 4, 2021).
I think the role that was played by the practice and reflection sessions, is they helped me become conscious of the things that I was lacking, actually because what I realized was when I compare my lessons to that of my peers or to the things that the other people were saying I actually saw a lot of things that I missed (Student teacher 8, 2021).

Discussion and implications for practice
The pattern that emerged in relation to the research question which was about what and how student teachers learnt from implementing a lesson design approach that draws on principles derived from the science of learning, can be encapsulated as follows: From the student teachers' perspectives, the lesson design approach helped them to develop a sound understanding of the nature of learning and that such an understanding is important because teaching is ultimately about helping learners to learn. In addition, they articulated that invoking the principles forced them to be more metacognitive and intentional in designing the lessons, moving beyond teaching methods and classroom discipline to a focus on what the intended learning would involve and how to best guide and support the anticipated learning of learners. They were also of the view that the lesson design approach is transferable, i.e., that it is suitable to use in varying contexts because it is not dependent on the availability of resources. This signals to us that they understood that the principles are not context dependent, but that they should be interpreted in relation to contextual variables.
Although we were interested in the student teachers' views on their learning in relation to the lesson design approach, we are also aware of the limitations of self-reporting in research. For this reason, we tested the above pattern against the lessons that student teachers designed, and we conducted stimulated recall interviews (Calderhead, 1981) on the lessons with a view to further probe their understanding. The lessons (and stimulated recall interviews) confirmed that student teachers grasped how the principles could and should inform teaching. They developed strong mental models/representations (Ericsson & Pool, 2016) of what designing significant learning experiences for learners involves. These mental representations are important for pattern recognition and problem solving when designing lessons within varying contexts, which is a given in teaching. The principles that featured prominently in lessons were those related to eliciting learners' prior knowledge and building on this knowledge; focusing learner attention and engaging learners throughout the lesson, without overloading their short-term memory; and creating a positive learning environment (invoking the principle that cognition and emotions are intertwined). The lessons also showed that they were able to connect teaching practices/techniques to the principles that they invoked. The practice of using open questions featured prominently in relation to eliciting prior knowledge, focusing learners' attention and thinking, and checking for understanding throughout a lesson. Other practices that featured frequently were the use of peer/ group learning activities to support cognitive engagement; using multiple modalities to present content in chunks interspersed with assessment for learning tasks to avoid overloading learners' working memory; and using playful learning activities to create an emotionally positive classroom environment.
As mentioned above, the data suggests that the student teachers grasped that teaching should ultimately be geared towards enabling learning; that they developed sufficient competence to use the lesson design approach thoughtfully; and that they saw the value of the lesson design approach for teaching in varying contexts. We reflected on the factors that may have contributed to this positive outcome and have concluded that requiring the student teachers to adopt an inquiring and metacognitive stance, as well as the way in which the student teachers were guided, was integral to this apparent success.
The same principles that were articulated for designing lessons, were invoked to guide student teachers and were modelled to the student teachers. The teacher educators used both implicit and explicit modelling (Acquah et al., 2020;Warren, 2019). They deliberately displayed behaviors, teaching practices and postures to promote student teachers' pedagogical awareness (Loughran & Hamilton, 2016;Lunenberg et al., 2007) of the science of learning principles and their implications for teaching. For example, baseline questionnaires were used at the start of the academic year to determine student teachers' existing views on what learning entails and the science of learning principles that they were about to encounter. Their responses to the questionnaires were used as a springboard during lecture discussions, thus modelling the principle that teaching should start with learners' existing knowledge. To invoke the principle that learning requires attention and cognitive engagement, learning tasks with open-ended higher-order questions at their core were used to focus the student teachers' attention and engage them in deep thinking about the meaning of the content. The teacher educators invoked the principle that cognition and emotion are intertwined by creating a safe, supportive, yet challenging learning environment. This was done by using a consistent approach to guiding student teachers during a time of stress , so that student teachers knew what to expect, thereby creating a sense of safety. In addition, student teachers were challenged to move beyond their comfort zones while providing them with ample support via, e.g., tutoring, email, and WhatsApp groups. Explicit modelling involved the teacher educators articulating their thought processes by giving a rationale for using specific behaviors, teaching practices and postures, and in this way also modelling metacognition at work. We agree with Russell (1997) who said: "How I teach IS the message" (p. 32). We also agree with Loughran and Hamilton (2016) that "modelling teaching as a way of creating opportunities for students of teaching to make sense of pedagogical practices and to support their professional learning" (p. 14) should be a given in teacher education.
Secondly, student teachers were required to adopt an inquiring and metacognitive stance when designing lessons, which meant using inquiry (guided mainly by why, how, and when questions) to deepen their thinking about teaching practices and decisions; and to articulate the rationale of the planned teaching decisions in relation to principles derived from the science of learning literature -making their thinking explicit. Thus, we required them to put inquiry, coupled with metacognition (thinking about their thinking) to work when designing lessons. We argued that bringing such a stance to play would go a long way to laying the basis for the continued development of adaptive expertise.
Another way in which we aimed to guide student teachers toward developing adaptive expertise, was to employ deliberate practice. The iterative and cyclic way in which the lesson design process unfolded enabled continuous and deliberate practice. During the first cycle, student teachers designed the "introduction" phase of the lesson. During the second cycle, they designed the "body" of the lesson and they had to include a revised version of the introduction phase incorporating feedback they received from teacher educators and peers. In the third cycle, the student teachers submitted a modified version of the lesson's introduction and "body" (again incorporating feedback received), and they designed the "consolidation" phase of the lesson followed by refining it based on feedback received. In the fourth (final) cycle, the student teachers self-assessed the lesson holistically, and then refined the entire lesson. Student teachers were involved in practice and reflection sessions (involving approximately 15 student teachers per group and one teacher educator) throughout the lesson design process. In addition, to provide student teachers with the opportunity to share their lesson design decisions and to reflect on these, prompted by feedback, the sessions also engaged student teachers in the deliberate practice of specific teaching practices related to the science of learning principles. Student teachers would, for example, practice how to elicit learners' prior knowledge by asking purposefully chosen open-ended questions to their peers. The teacher educator and their peers would then provide feedback on the appropriateness of the questions they planned to use.
The iterative approach used is similar to microteaching lesson study (Fernandez, 2010), which involves student teachers in the cyclic development of lessons, coupled with actionable feedback and reflection. Fernandez (2010) reported that this type of deliberate practice supports the development of student teachers' knowledge of how to design and teach powerful and purposeful lessons. Also, what was done is akin to what Ericsson (2014) noted as important for developing adaptive expertise. Firstly, the student teachers were provided with challenges that required them to go beyond their current levels of performance, and the group sessions provided a safe learning context that allowed for feedback and gradual refinement by repetition. The latter happened via the iterative process that was followed. Also, the way in which the lesson design approach was taught to the student teachers involved them in exploration, which allowed for error making. This benefits adaptive expertise "if a link is made between the errors and the to-be-learned knowledge. Establishing this link leads to deeper understanding of the domain, resulting in a knowledge representation beneficial for adaptive expertise" (Carbonell et al., 2014, p. 26).
Based on the interviews, and the lesson plans that were used to verify views that the student teachers expressed, we can claim with some confidence that the student teachers did indeed develop the beginnings of adaptive expertise. We draw here on the conclusions that Carbonell et al. (2014) has made about the nature of the domain specific knowledge and skills of adaptive expertise. We do believe that the student teachers constructed a sufficient knowledge base of the principles derived from the science of learning to inform thoughtful lesson design and, by implication, teaching. We are also of the view that the knowledge that they gained about the principles was organized in a way that will facilitate application to various situations. According to Carbonell et al. (2014), the knowledge representation for adaptive expertise "in terms of organization, abstraction, and consolidation, is de-contextualization, weakening the link between situation and solution" (p. 20). This was noted by the student teachers-that the principles can be used in varying contexts. Also, it is our hope that the metacognitive reflection, which was required throughout the process, developed a commitment to self-assessment through metacognitive reflection (Hammerness et al., 2005) which is important for the continued development of adaptive expertise.

Limitations of the research
The research was conducted during a time when the COVID-19 pandemic severely restricted student teachers' access to schools. It was thus not possible to observe student teachers teaching the lessons that they designed. We claim that we have good evidence that the student teachers learned to "think like a teacher" (Feiman-Nemser, 2008), in relation to creating significant learning experience for learners, but we have little evidence that they were able to enact this thinking while they taught. Thus, we do not know whether the approach that we used addressed the enactment problem (Kennedy, 1999) -whether they were able to put their intentions into action. This remains a perennial issue in teacher education. A current research project in progress addresses how preservice teachers enact their understanding of designing lessons that place learning central when teaching these lessons during school practicum.

Conclusion
The research reported in this paper set out to explore what and how student teachers learnt from a lesson design approach that draws on principles derived from the science of learning, to prepare them for teaching.
We conclude that an approach to lesson design that draws on the science of learning to help student teachers develop as adaptive experts on creating significant learning experiences for learners, has much to offer to pre-service teacher education. We also recognize that other lesson design approaches which foreground other priorities may be equally successful for teacher preparation. However, we do contend that, notwithstanding the approach followed, pre-service teachers will benefit from an approach that is modelled by teacher educators, and which employs an iterative process that uses deliberate practice to allow for exploration and errors; to provide feedback that induces reflection on how to improve; and to provide opportunities for the improvement to be implemented.