Learning to Argue Through Dialogue: a Review of Instructional Approaches

Over the past 20 years, a broad and diverse research literature has emerged to address how students learn to argue through dialogue in educational contexts. However, the variety of approaches used to study this phenomenon makes it challenging to find coherence in what may otherwise seem to be disparate fields of study. In this integrative review, we propose looking at how learning to argue (LTA) has been operationalized thus far in educational research, focusing on how different scholars have framed and fostered argumentative dialogue, assessed its gains, and applied it in different learning contexts. In total, 143 studies from the broad literature on educational dialogue and argumentation were analysed, including all educational levels (from primary to university). The following patterns for studying how dialogue fosters LTA emerged: whole-class ‘low structure’ framing with a goal of dialogue, small-group ‘high structure’ framing with varied argumentative goals, and studies with one-to-one dialectic framing with a goal of persuasive deliberation. The affordances and limitations of these different instructional approaches to LTA research and practice are discussed. We conclude with a discussion of complementarity of the approaches that emerged from our analysis in terms of the pedagogical methods and conditions that promote productive and/or constructive classroom interactions.

supports knowledge construction, by situating learned facts, or knowledge, within evidence-based explanatory frameworks (Leitão 2000). In fact, extensive research has shown that by engaging in argumentative practices students from childhood to adulthood learn how to better structure their reasoning, consider alternative viewpoints (e.g., Kuhn et al. 2016a;Larrain et al. 2019;Nussbaum and Edwards 2011;Reznitskaya et al. 2009), and develop more nuanced understandings of the topics they argue about (e.g., Asterhan and Schwarz 2007;Iordanou et al. 2019;Zohar and Nemet 2002). Moreover, several scholars (e.g., Rapanta 2021; Kuhn 2018Kuhn , 2019Osborne et al. 2013) have confirmed that argumentation can be used as a pedagogical method to help students think critically, solve problems, and make decisions that concern their lives as individuals, as members of a society, and as world citizens.
Argumentation may involve an individual discourse activity, like argumentative writing (Klein et al. 2019) or graphical representation (Noroozi et al. 2018;Nussbaum 2008), or it may take the form of a social discourse activity in which dialogue partners collaboratively construct, critique, and reconcile arguments in the service of knowledge construction (Kuhn 2015). This view, rooted in social constructivist theories of learning, explains how skills of argument emerge and are refined on the social plane before becoming internalized to manifest as individual reasoning and learning (Billig 1987;Kuhn and Crowell 2011;Mercer and Howe 2012). However, for this socially rooted learning to take place, an immersion in dialogue is necessary (Cavagnetto 2010;Prawat 1991). According to Chinn and Clark (2013), when students learn how to argue through dialogue, they learn 'how to engage effectively in the practice of argumentation ' (p. 321).
The current research is divided regarding what this 'effective engagement' entails and what it takes for researchers and educators to achieve it (Asterhan et al. 2020;Kim and Wilkinson 2019). On one extreme, there is the non-instrumental view, in which dialogue represents a form of social meaning-making, valuable in itself and not defined by external gains or pre-defined goals (Clarà 2021). From this perspective, learning to argue naturally emerges from adopting dialogic moves that facilitate the exchange of ideas or perspectives, such as asking open-ended questions, elaborating on others' ideas, exploring competing viewpoints, coordinating views, and reflecting on dialogue metacognitively (Hennessy et al. 2016;Howe et al. 2019). On the other extreme, there is the intentional instructional framing of dialogue to produce specific argumentative gains. From this perspective, learning to argue involves using dialogue to define problems, produce claims, critiques and rebuttals using evidence, and coalesce arguments in ways that produce more accurate, developed, or sound outcomes (Baker 1999;Chen et al. 2016;Zohar and Nemet 2002).
Adopting the non-instrumental point of view, engaging in dialogue is the primary focus on LTA, whereas adopting the argument-oriented point of view, engaging in argumentation is the primary focus of LTA. Independently of the approach taken, dialogue needs to have certain characteristics and/or lead to certain gains so that it can fulfil its learning potential (Resnick et al. 2018). Although extensive research is available on the educational dialogue that leads, directly or indirectly, to LTA outcomes, these outcomes are not defined similarly across studies, and the methods adopted to define and measure them do not always involve controlled comparison to traditional teaching methods, so that valid conclusions about the effectiveness of instructional approaches can be drawn (Hoadley 2006). Our goal with this review is to better distinguish and define the range of approaches taken by researchers and teachers to elicit and advance students' reasoning in the social context of classroom interaction, with effectiveness being defined either in terms of interventions on the quality of discourse and dialogue, or as a characteristic of the dialogue itself. By characterizing and mapping these various approaches to exchanges between speakers who hold opposing views on a topic. From this perspective, divergent views fuel a form of discourse in which individuals draw out and challenge the claims and evidence for each other's conclusions (Felton and Kuhn 2001;Kuhn and Zillmer 2015). Focusing speakers on the differences in their views encourages them to explore the relative strengths of arguments in ways that are often absent when speakers focus on similarities in their perspectives (Thiebach et al. 2016). As a result, the social dynamic of dialectical exchange creates a context in which speakers naturally prompt one another to produce more fully elaborated and carefully examined arguments than might be later observed in independent reasoning (Kuhn et al. 1997;Kuhn 2019;Larrain et al. 2019). This results in the development of the social, critical thinking skill of 'antilogos', that is, one's ability to identify limitations in one's own assumptions and positions, which may lead to totally different or even oppositional assumptions and positions (Billig 1987).

Cognitive Outcomes
Several higher-order cognitive and metacognitive processes are inherent in argumentative dialogue due to the complexity and diversity of the task of putting forward a position, defending it with sufficient and relevant evidence, addressing counterarguments, generating valid rebuttals to further strengthen one's own side, or making revisions to one's argument in light of valid critique. Together, these activities draw on a set of cognitive, meta-cognitive and meta-strategic resources (Rapanta et al. 2013), including inferential abilities, evaluation abilities, argument appraisal, as well as more advanced strategies of theory-evidence coordination and undermining an opponent's point of view with counterevidence. In a climate of fake news and alternative facts, learning to identify, assess, and integrate information from sources to draw valid conclusions is a direct benefit of argumentative dialogue.

Epistemological Outcomes
Argumentative reasoning, including both the construction and evaluation of arguments, and epistemic cognition are highly intertwined (Chinn et al. 2011;Iordanou et al. 2016). Argumentative dialogue, as a social manifestation of argumentative reasoning, helps epistemic cognition to become explicit, especially when it comes to the acquisition of norms of what counts as a good argument and argumentative dialogue (Kuhn et al. 2013). As argumentative dialogue externalizes thinking, it creates a context for reflective judgments about the validity of each speaker's claims and evidence. As a result, it opens the door to new insights into the nature of knowing, standards for judging certainty, and practices for constructing knowledge from carefully vetting claims and evidence.
Although not all educational dialogues are aimed at argumentation as a goal, argument-related gains like the ones described above are a part of the learning potential of dialogue (Resnick et al. 2018). However, when dialogue is not designed to be argumentative, those social, cognitive, and epistemological gains often emerge as desired by-products or even manifestations of the dialogic process, even though they were not the direct object/-ive of dialogue. To be able to bridge the two approaches, i.e., the more instrumentalist one, directly aiming at argument gains, and the more ontological one, which welcomes argument gains as part of the dialogic engagement (Clarà 2021), we provide below a conceptualization of LTA instructional approaches which applies to both cases.

LTA Instructional Approaches
According to Morrison et al. (2019), the fundamental components of any instructional design, no matter what the designed learning activity/environment is, are: the Objectives, which 'provide a map for designing the instruction and for developing the means to assess learner performance' (p. 17); the Methods, which define how the subject content and/or skills are best learnt; the Learners, referring to the characteristics of learning for whom the activity/ environment is designed; and the Evaluation, referring to ways to determine the extent to which learning is achieved. Applying this instructional effectiveness model directly to the LTA literature is not possible, due to the great variety of approaches that exist within as discussed above. Therefore, what we propose is to transform the generic instructional effectiveness model by Morrison et al. (2019) into a framework for reviewing the LTA literature, which can adapt to the diversity of approaches encountered within. Our MeDOL framework adapts Morrison et al.'s (2019) effectiveness components as follows: Methods refer to the authors' approach of framing educationally effective dialogue, and to the fostering methods used to increase LTA outcomes; Dialogue goals refer to the epistemic goals pursued by the study participants during the LTA activity; Outcomes refer to the participants' LTA gains described in each study; and Learners refer to the students and learning main characteristics described in each study such as age/educational grade, learning structure (i.e., whole class, small groups, dyads, or mixed), and disciplinary field.

Methods
It has been argued that framing methods shape, or at least characterize, the process by which educational goals are achieved through dialogue (Ford and Wargo 2012). When the goal is LTA, dialogue can either be framed a priori as argumentation, or emerge as a result of the dialogic activity. In this sense, argumentative dialogue may emerge through a more structured approach, where the learning environment is intentionally designed to produce specific argumentative interactions and outcomes; or it may follow a less structured approach, where the learning environment is designed to promote dialogic norms, without specifically focusing on the production of particular argumentative interactions or outcomes, as the ones described above. We will henceforth refer to this distinction as 'high vs low structure' approaches to argumentative dialogue.
Low-structure approaches to educational dialogue do not explicitly focus on structuring argumentation as a goal-oriented activity itself, but rather on establishing norms for dialogue and its productivity. In this approach, educational (argumentative) dialogue is productive insofar as participants actively engage in exploring different perspectives. Argumentation may emerge as a natural result of exploring these perspectives, but it is not set as the primary outcome. An example of this approach is 'exploratory talk' (Mercer 2004).
In contrast to low-structure dialogic approaches, the high-structure ones focus on argumentation as an explicit goal, and not a by-product of students' interactions. This is primarily done through focusing on argumentative knowledge construction, therefore on the types of dialogic activities students should engage in so that some type of new knowledge or understanding can emerge. This type of educationally effective dialogue is particularly common within the fields of computer-supported collaborative learning (CSCL) (see, for example, the argument scripting approaches-Jermann and Dillenbourg 2003) and science education (see, for example, the Science Writing Heuristic approach- Hand et al. 2021).
A separate case of high-structure dialogic approaches focuses on the resolution of a controversy as the vehicle for promoting advances in argumentation. Within this approach, which can be called dialectic (Asterhan 2013), the characteristics of the issue and the nature of the task assigned to students as part of its resolution are of high priority in terms of designing the interaction. Regarding the issue, the more controversial it is, the greater the possibilities that authentic argumentation will emerge, in the form of a critical discussion (van Eemeren and Grootendorst 1992;Walton and Krabbe 1995). Moreover, a clear need for the issue resolution must be present either in the form of a dilemma (e.g., Kuhn 2018;Zohar and Nemet 2002), or in the form of a decision among multiple alternatives (e.g., Jiménez-Aleixandre 2002; Garcia-Mila et al. 2013).

Dialogue Goals
From a dialogue theory perspective, the identification of types of dialogue according to dialogue goals has attracted researchers' attention (see, for example, Walton 1989Walton , 1998. When it comes to educational contexts, it is still not clear what such a typology should take into consideration as a 'goal'; therefore, different 'goal' approaches result into different dialogue types. For example, Osborne et al. (2016) proposed two main interlinked goals for science argumentation: constructing and critiquing scientific explanations. Keefer et al. (2000) propose four types of educational dialogues by crossing 'convergent' or 'divergent' participant approaches, on one hand, with how successful they are in fulfilling their goal, giving: (a) a successful divergent approach called 'critical discussion' (term borrowed from Van Eemeren and Grootendorst 2003), (b) a non-successful divergent approach called 'eristic discussion', (c) a successful convergent approach called 'explanatory inquiry', and (d) a non-successful convergent approach called 'rapidly reaching consensus'.
In our view, both proposals discussed above are insufficient to capture the complexity of dialogue goals in LTA instructional settings. On one hand, Osborne et al.'s (2016) proposal clearly focuses on the epistemic aspects of instructional framing for LTA without refining the dynamics of knowledge construction and critique. On the other hand, Keefer et al.'s (2000) focuses on the dialogue fluidity and versatility 'on the go', and not as part of an instructional framing. We view dialogue goals as epistemic goals enacted by the student participants in each dialogic context. Examples of such dialogue goals are the ones proposed by Berland and Reiser (2009), namely: sensemaking, articulation, and persuasion. Extending Berland and Reiser's (2009) initial proposal, sensemaking dialogues aim at making sense of what others say and/or a specific phenomenon under consideration. Articulation focuses on either articulating the relationship between sources of evidence or coordinating theories with evidence. It is about understanding at least two types of data and establishing the relationship between them. Finally, persuasion dialogues focus on either arriving at a consensus (deliberation) or proving one's side or position as the best according to epistemic standards. When it comes to persuasion as an ultimate goal in educational dialogue, a deliberation phase is always necessary, particularly when a final decision must be made. For this reason, and also to avoid the misconception that persuasion must be confrontational (Kruger 1993;Micheli 2012), we can refer to this goal as a deliberation goal, rather than persuasion

Outcomes
The traditional distinction between argument1 and argument2 (O'Keefe 1992) proposes two legitimate and complementary approaches to argument, one that focuses on argument-as-product (i.e., something that a person makes) and another that focuses on argument-as-process (i.e., something that a person engages in).
Arguments-as-products may comprise both structural and functional elements of discourse (for more about this distinction, see Rapanta et al. 2013;Macagno 2016). In terms of structural elements, effective argumentative reasoning might take some of the following forms: (a) effective integration and use of evidence (i.e., Berland and Reiser 2011;Kuhn et al. 2013); (b) effective integration of arguments and counterarguments, i.e., balanced or dialogical arguments (i.e., Kuhn and Udell 2007;Polo et al. 2016); and (c) effective use of counter-arguments and rebuttals (i.e., Kuhn and Udell 2003;Crowell and Kuhn 2014). It may also relate to the elaboration of arguments, as with the structural elements proposed by Toulmin (1958). More precisely, data, warrants, and backings are related to the identification and use of evidence, whereas claims, qualifiers, and rebuttals are related to the skill of construction and critique. Of course, to be able to assert that the use of specific argument elements is effective, other pragmatic criteria may be needed, such as conceptual complexity, coherence, and relevance.
In terms of argumentative function, effective dialogue takes the form of discursive moves that elicit reasoning, operate on reasoning, or redirect conversation. Early work in the transactive nature of dialogic reasoning (Berkowitz and Gibbs 1983;Kruger 1993) plays an important role in many functional models of argumentative reasoning. This work focuses on the ways in which speakers engage with and operate on each other's thinking through dialogue, with an emphasis on how dialogue can be used as a way to socially elicit, elaborate, critique, and revise arguments. Generally, analyses of discursive moves in argumentation focus on the ways in which instructional interventions, scaffolds, or contextual variables facilitate these discursive processes. Some studies also go beyond the analysis of individual moves to look at how these moves are coordinated to form either coherent dialogic processes or effective argumentative strategies. It is common to speak of 'dialogic transactivity' in the first case, and of 'dialectic transactivity' in the latter (Vogel et al. 2016).
In recent years, social scientists have begun to challenge the notion that good argumentation involves distilling rational argument from the soup of social and emotional conflict. Instead, argumentation is seen as a dynamic interplay of social, emotional, and cognitive functions (Asterhan 2013;Gilbert 2004;Plantin 2004). On the one hand, emotions play an important role in promoting active engagement in reasoning and complement rationality (Lipman 2003). On the other hand, there is clear evidence that negative emotions drive the distortion of facts, increase miscommunication, and lead arguments astray in disputative argumentation (Polo et al. 2016). For example, Polo and her colleagues (Polo et al. 2016) propose that attempts to maintain positive emotion may be the reason that cumulative talk fails to draw out the kind of constructive criticism found in exploratory talk. Therefore, the ability to modulate and navigate emotions in a dialogue is an important component of argumentation (Andriessen et al. 2011).
There is also a social dimension to the regulation of argumentation, since the norms of social interaction can also have a direct impact on the progress of argumentative dialogue. In fact, there seems to be a close relationship between norms for social interaction and emotional tension in argumentative dialogue. At the most basic level, turn-taking is a social norm that, when broken, can negatively impact dialogue. When speakers talk over one another, cut each other off, or dominate the conversation, they undermine the appearance of good faith, and threaten other speakers' face, i.e., perceived public image (Chiu 2008). Conversely, positive social regulation, such as active listening among peers, and between teacher and students (Alexander 2017;Michaels et al. 2008), can serve to facilitate effective argumentative dialogue by creating a safe space for the critical evaluation of ideas.
Finally, metadialogue (Krabbe 2003) is a socio-epistemic regulator of argument-as-process that contributes to effective argumentation and at the same time functions as a manifestation of argument gains. It may include appeals to standards for valid reasoning, where speakers make an explicit statement about the nature of claims and evidence and the ways in which they are coordinated to draw a conclusion (Macagno et al. 2015). Metadialogue can also be used to regulate the goals, process, and outcomes of argumentative dialogue (Felton et al. 2015a, b): speakers may explicitly coordinate goals, focus dialogue on points of disagreement, or propose solutions to apparent contradictions in their views. Finally, metadialogue can be used to impose social norms for regulating argumentative dialogue (Kuhn and Zillmer 2015;Michaels et al. 2002). Across these disparate applications, metadialogue can be understood as the conscious and explicit attempt to optimize the social construction of arguments. Seen in this way, metadialogue represents a form of epistemic cognition operating on the process of argumentation (Kuhn et al. 2013). Indeed, metacognitive knowledge and regulation of argumentation are naturally epistemological because of the role that argumentation plays in establishing the strength, validity, truth, or applicability of conclusions through the coordination of claims and evidence. When speakers choose to direct or correct the course of argumentation with metadialogue, they manifest epistemological aims, knowledge, and values about argument.

Learners
Finally, all the above (Methods, Goals, Outcomes) makes sense because it works for a concrete type of learner in a concrete context. The learner characteristics expected to be found in all empirical reviewed studies are: (a) the age/educational grade; (b) the disciplinary field or topic on which the dialogue is held; and (c) the setting of the learning situation, meaning whether the dialogue take place in whole-class discussion format, in small groups, or in one-to-one settings.

The Present Study
To address the existing tension between 'dialogue' as the main focus and 'argumentation' as the main focus of research, we propose to look at LTA as a common instructional process to pursue either explicitly or as a by-product. Our approach is different to theoretical approaches focusing on dialogue purposefulness (Alexander 2017) or argumentation goal-orientedness (Walton 2013): rather than looking at the concrete aims participants strive at during their engagement in argumentative dialogue, we opt for studying the different ways in which learners' engagement in the practice of argumentation is framed, fostered, and evaluated by educational researchers. We propose that by studying the literature in this way, we might better understand how different approaches to LTA might inform and complement one another. We believe that doing so might bring more coherence to our understanding of how to foster argumentative dialogue and to what ends.
Our research questions are: 1. How do educational researchers frame argumentative dialogue and its gains in instructional settings? 2. How is argumentative dialogue scaffolded and fostered in different contexts?

Methods
The integrative review was selected as the most appropriate way to address the research problem of mapping existing educational research focusing on learning to argue (LTA) through dialogue. Given the complexity of argumentative discourse and the breadth of approaches taken to describe and study the phenomenon, we decided to include both experimental and non-experimental studies in our review, whereas a meta-analysis would limit our scope to experimental studies only (Whittemore and Knafl 2005). In addition, our goal was not to measure the effectiveness of dialogue on students' learning (such a goal would have been impossible given the variety of methodological approaches), but to understand how learning to argue is actually carried out in different instructional contexts. We therefore aimed at studies from both educational dialogue and argumentation fields, while limiting our search to those studies that offered an evaluation of the quality of discussions revealing or leading to some type of learning to argue gains. The indicators we used for the LTA evaluation are included in the search keywords described below.

Sample
A systematic search of peer-reviewed articles was conducted using four large databases: ISI's Web of Science (WOS), Elsevier's Scopus, EBSCO, and PROQUEST. We intentionally aimed at studies explicitly focusing on some manifestation and assessment of dialogue quality, defined in a variety of ways, such as productive, constructive, effective, strategic, or persuasive. For each one of the searches, the keywords used were: 'argument*' or 'dialog*', on the one hand, and 'effect*' or 'construct*' or 'productive' or 'strateg*' or 'persuas*' as LTA quality indicators, on the other.
The initial search yielded 3013 results, excluding unpublished manuscripts, book chapters, and conference proceedings, to ensure a higher quality of the studies due to stricter peer review criteria. A first screening of these documents based only on the title resulted in a sample of 945. This reduction was mainly due to the frequent use of the term 'argument' in its ordinary, non-technical sense. The pool was further reduced after the exclusion of duplicates, as several databases were simultaneously considered, to 761 articles. A second screening based on the abstract resulted in 341 articles. For this second screening, we used the following inclusion criteria: (a) that the article was empirical rather than theoretical or methodological; (b) that the article addressed K-16 education; (c) that the study addressed teacher-students and/or student-student interactions in either face-to-face or computer-supported classroom contexts. The selected articles underwent a third screening based on their full text. To the previous inclusion criteria, the following two were added: (a) that the quality of dialogue and/or reasoning were assessed in some way; and (b) that the interactions were held in the classroom or other educational setting (e.g., computer laboratory). This final screening resulted in 145 articles, with two cases of pairs of articles reporting on the same studies; therefore, we ended with a total number of 143 studies published between 1997 (date of the first included source) to 2020 (until November, and only finally published documents).

Coding Process
All 143 studies were coded in terms of the MeDOL framework presented in the theoretical part of this paper. Eleven coding categories emerged from our analysis (Figure 1). Four of these variables (coach-based, materials-based, peers-based fostering methods, and argument-as-process) were openly coded, and the remaining seven (dialogue approach, task-based scaffolds, dialogue goal, argument-as-product, dialogue setting, educational grade, and subject field) were defined a priori, with sub-categories explained below.
During the coding process, the two authors randomly selected 20% of the studies and double-coded them independently for three high-inference variables, namely dialogue approach (low structure/high structure/dialectic), dialogue goal (sensemaking/articulation/deliberation), and argument-as-product (main/elaborated/complex/dialogic/dialectic). The inter-rater reliabilities were satisfying for all three variables (κ = .776, κ = .727, and κ = .702, respectively), and disagreements were resolved by discussion.

Dialogue Approach
As mentioned in the theoretical part of this review, three sub-categories were used to describe the different approaches to LTA: (a) low-structure dialogic, (b) high-structure dialogic, and (c) dialectic. A main distinction between the high versus low structure approaches to argumentative dialogue is that in the low structure approach, dialogic interaction has the predominant 'formative potential' (Chin and Teou 2009), shaping students' ideas and thinking by creating a shared dialogic ethos (Littleton and Mercer 2013). In contrast, in the high structure approach, it is the design of the learning environment that supports students' enactment of meaningful argumentative practices (Ravenscroft 2000;Wu and Krajcik 2006). Similarly, a main distinction between the dialectic and the high structure dialogic approach is that the high structure guides students through a defined set of procedures to reach a specific outcome (e.g., an answer to a problem), whereas the dialectic approach focuses on eliciting opposing views to encourage each party to consider their arguments in a framework of alternatives.

Task-based Scaffolds
These refer to task components that have been shown to be relevant or significant for the quality of argumentative dialogue in the various studies. Among the task-based scaffolds, we pre-defined the following sub-categories: (a) the issue(s)/topic discussed; (b) the class organization (seating/group structure); (c) how the task is organized in terms of contents and actions (task structure/script); or (d) a specific instructional technique adopted as a task activity (e.g., philosophical circle, Collaborative Reasoning, etc.).

Dialogue Goal
As mentioned in the theoretical part of this review, three sub-categories were used to describe the different dialogue goals of LTA: (a) sensemaking, (b) articulation, and (c) deliberation/ deliberative persuasion. According to Dougherty et al. (2000), 'people cannot collectively use knowledge unless they first make shared sense of it' (p. 323). Therefore, sensemaking is a starting point for any constructive dialogue (i.e., a dialogue that explicitly aims at constructing new knowledge) to take place. When learners engage in 'sensemaking' as their main task, they question each other, clarify content, build on each other's ideas, and share their individual explanations about a phenomenon. As part of this task-process, several cognitive processes can take place such as: describing multiple aspects of a phenomenon, comparing two or more phenomena, or describing different types/cases of a phenomenon (Meyer et al. 2015).
Examples of studies focusing on sensemaking as a primary task for students to engage with are: Lee, Kang, and Kim (2015) 1 in science (students were asked to provide an explanation of a scientific phenomenon using modelling strategies) or Chisholm and Loretto (2016) in a language classroom ('how students made meanings in interaction by dialoguing with other students, texts, and ideas', p. 1).
Articulation focuses on either articulating the relationship between sources of evidence and/ or coordinating theories with evidence. It is about understanding at least two different types of data and establishing a relationship between them. In articulation-oriented dialogue tasks, students exchange, contrast, and coordinate their interpretations of a phenomenon using some type of data (information) as evidence. Based on Baker (1999), Veerman et al. (2000) define articulation as a knowledge transformation process, during which 'already stated information is evaluated and integrated into the collective knowledge base in such a way that, a new insight or a new direction transpires, that can be used to answer questions or to solve problems' (p. 272). Although sensemaking prepares the ground for joint knowledge construction and learning with others, articulation makes this goal explicit. Examples of studies focusing on articulation as a primary task for students to engage with are: Kim and Song (2006) in science (all students were asked to defend their scientific evidence-based reports in front of the rest of their classmates who would challenge it with questions, without the goal being that of choosing the report that best explained the phenomenon at hand), or Jadallah et al. (2011) in a language classroom ('One of Ms. Jackson's principal objectives was to have children support their arguments with story evidence', p. 204).
Finally, deliberation focuses on either arriving at a defending one's position on a topic or reaching consensus after weighing alternatives based on epistemic standards. The activities characterizing deliberation dialogue involve addressing explicit disagreement to reach a conclusion or decision or final state of a debate, while revising one's position as necessary. Defining deliberation as the main task of learning to argue implies an explicit focus on increasing the plausibility of one position, either through accepting it as the most accountable one (e.g., by consensus or compromise) or through persuading the other party using logical arguments. Sensemaking and articulation are both elements of the deliberative process, as opposing claims must be first elaborated and then substantiated in order to be critically evaluated. Examples of studies focusing on persuasion/deliberation as a primary task for students include Felton et al. (2015a, b), where science students used critical dialogue to evaluate solutions to a socio-scientific problem, or Muller-Mirza et al. (2007) 2 , where students engaged in a historical debate through role-playing.

Argument-as-Product
The sub-categories and codes we used to capture the argumentative reasoning outcomes, when these were expressed as functional or structural products of discussion (see theoretical part of this review) were: claim (C), reason (R), claim quality (Cq), evidence (E), questions (Q), Toulmin's (1958) Argument Pattern (TAP) structure, e.g., claim-data-(warrant)-backing, connection between claim and reasons (C/R), evidence quality/types (Eq), types or quality of reasons (Rq), transactive moves (T), counterargument and/or rebuttal (CAR), evidence-based counterargument and/or rebuttal (CAR/E), revised or integrated argument (RE), quality/types of counter-argumentation strategies (CARq), use of critical questions by students (Qq). Table 1 shows the description of the five levels of argument quality, described previously, based on the presence or combination of the above elements.

Instructional Framing Approaches to LTA
To explore patterns in framing argumentative dialogue, we looked at the relationship between 'dialogue approach' and 'dialogue task,' testing their independence using Fisher's exact test, with Cramer's V (φc) to look at effect size. Adjusted standardized residuals of +/−2 were used to determine the contribution of individual cells in the omnibus tests (Beasley and Schumacker 1995). The test yielded significant results (p < .0001), with a moderate effect size (φ c = .429). Upon analysis of standardized residuals, the four relationships driving our findings were low-structured sensemaking, high-structured articulation, high-structured deliberation, and dialectic deliberation (Table 2). Due to the significant frequency of their cross-tabbed observation, these four instructional framing stories emerging from the analysed studies were identified as study patterns (see Sandelowski and Barroso 2007, for a detailed view of how patterns are defined in literature reviews).
Argumentative dialogue evaluation was approached in terms of gains in argumentative reasoning (argument-as-product) and/or in socio-emotional and metadialogic gains in argumentation (argument-as-process). In terms of reasoning gains, we had previously identified five types or levels of arguments, comprising both structural and functional elements, namely: main, elaborated, complex, dialogic, and dialectic (see Table 1). A significant association was found between the 'study pattern' and the 'reasoning gains' using Fisher's exact test, p < .002, with a moderate effect size, φc = .329. Table 3 shows the reasoning gains types reported per study pattern. As can be observed in Table 3, a large majority of Pattern 2 (high-structured articulation) studies refer an elaborated structure of student arguments (i.e., a TAP, evidence-based claim structure), and a large majority of Pattern 4 (dialectic deliberation) studies focus on integrated arguments (i.e., integrating the dialectical argument-counterargument relationship), whereas a no clear association emerged for Pattern 3 (high-structured deliberation) and Pattern 1 (low-structured sensemaking) studies.
When it comes to the reported socio-emotional and metalevel gains, 48 out of the 108 pattern studies mentioned at least one of the two argument-as-process gains (i.e., socio-emotional and/or metalevel) as relevant for learning to argue. Of these, 17 studies exclusively focused on socio-emotional argument-as-process gains, 21 studies exclusively focused on metalevel gains, while eleven studies simultaneously considered both types of gains. These studies were distributed among Pattern 2 and Pattern 3 studies.
What types of different stories do the four patterns tell us regarding how learning to argue is achieved? Below we will give a descriptive account for each one of the four identified patterns, composed of different instructional approaches, tasks, and outcomes related to the 'umbrella' learning to argue (LTA) instructional goal.

LTA Pattern 1: Low-structured Sensemaking
Studies belonging to the first pattern (low-structured sensemaking) tend to describe argumentative dialogue as an organic, whole-class, student-driven (Aukerman et al. 2016) or student-dominant (McNeill and Pimentel 2010) dialogue, aiming at the co-construction of ideas and shared interpretive authority among teacher and students alike (Chisholm and Loretto 2016). Within this study pattern, argumentative dialogue is a learning conversation , in which student agency and authority in discourse (Forman et al. 2017) is promoted. These studies tend to define argument quality as a description of different modes of participation such as public warrantability (Atwood et al. 2010), 'interthinking' (Aukerman et al. 2016), agreeing/disagreeing (Topping and Trickey 2007), or divergent thinking (Damico and Rosaen 2009). When they focus on the structural elements of the arguments produced by students, this is mostly the warrant or explanation of reasoning (e.g., Coker Jr and Erwin 2011; Frijters et al. 2008; Langer-Osuna 2015; Langer-Osuna and Avalos 2015; Lee and Majors 2003). In very few cases, they present some socio-emotional or metalevel gains as result of students' participation in dialogue. Some of these gains are explained below.

Reznitskaya et al. (2012) describe a study in which
Philosophy for Children (P4C) sessions provide a discussion frame suitable for the construction of new meanings and the reflection on the reasoning processes. Making sense of the concepts discussed and of the dialogue itself is therefore the primary goal set for the discussion. In the science context, Simon and her colleagues ) describe how students' engagement in scientific talk during whole-class discussions can be fulfilled in ways that children talk about their ideas, clarify their thinking, and, consequently, develop their capacity to reason. In both examples, the gains of dialogue are not separate from the dialogue itself, adopting a participation rather than an acquisition approach to learning (Sfard 1998). In particular, Reznitskaya et al. (2012) characterize LTA dialogues as inquiry dialogues, placing the focus on the fact that there are no right and wrong answers during P4C discussions. Simon et al. (2008) largely define LTA dialogues as argumentative interactions, as opposed to recall responses, characterizing the former as learning conversations. An emphasis on low-structure instructional framing is evident in both definitions. Other studies within this pattern group highlight some manifestations of LTA gains, either as a product or as a process. For example, Topping and Trickey (2007) emphasize that students explicitly agree or disagree based on reasons, and for that to be possible, a process of increased student participation and responsiveness is recommended. Sutherland (2006) presents more advanced reasoning gains as manifestations of LTA dialogue, such as posing higher-order questions and producing critical responses. Veerman et al. (2000) found out that checking conceptual information relevant to the argument was more important than argumentative moves. In their study, students' transactive reasoning gains were accompanied by reflection as a relevant metalevel (epistemic) process. Planning essays was another relevant metalevel (metacognitive) process accompanying low-structured sensemaking dialogue in a study by Coker Jr and Erwin (2011).
In short, sensemaking tasks, highly represented by LTA Pattern 1 studies, are requisite for advanced argumentation. Making claims clear and precise, justifying claims, and providing reasons for agreeing or disagreeing are common elements across LTA sensemaking tasks.

LTA Pattern 2: High-structured Articulation
Studies belonging to the second pattern (i.e., high-structured articulation) tend to conceive dialogue as a collective negotiation of meanings driven by the critical evaluation of evidence (e.g., Arvaja et al. 2000;Cavagnetto et al. 2010;Ford 2012;Hogan et al. 1999;Kim and Song  a Of the N = 108 studies belonging to one of the four dialogue study patterns, eight did not mention any argument reasoning gains, as they placed focus on other types of arguing skills (e.g., at a socio-emotional or metacognitive level) b Adjusted residuals >2 or <−2 2006; Sampson & Clark, 2011). In these studies, argumentation can be used to justify or explain, focusing on the use of evidence-based arguments to draw conclusions (e.g., Baines et al. 2009;Choi et al. 2014;Gillies 2013;Hsu et al. 2015;Kim and Song 2006;Kulatunga et al. 2013;Ryu and Sandoval 2012;Yun and Kim 2015) and/or on the generation, contrast, and evaluation of alternative explanations of the same phenomenon (e.g., Ford 2012; Sampson & Clark, 2011). High-structured dialogue studies focusing on articulation as their major task include operationalizations such as students challenging or questioning each other about evidence (Choi et al. 2014), interpreting and evaluating data (Selcen Guzey and Aranda 2017), or engaging in scientific inquiry (Kim and Song 2006). When it comes to gains in argument-as-process, Pattern 2 studies tend to place an equal focus on socio-emotional and metalevel processes. For instance, Alexopoulou and Driver (1996) focused on the extent to which students considered and evaluated their own and their peers' assertions instead of simply presenting their views, so that they avoid repetition/circular argument. On top of that reasoning gain, the researchers focused on the socio-emotional process of avoiding tensions and conflict through balancing power in interaction, and on students' willingness and openness to negotiate ideas at a metadialogical level. Similarly, Baines et al. (2009) focused simultaneously on the socio-emotional process of achieving egalitarian student participation through group maintenance versus group blocking, and on the metalevel process of metatalk about the group itself and not about the task. Another example is Ryu and Sandoval (2012) whose main presented student gains were students' listening to each other, at a socio-emotional level, and students' evaluating arguments developing evidentiary norms, at a 'meta' level.
Given the great emphasis on socio-emotional and meta-level processes, as explained above, we might also expect more explicit focus on sophisticated argument products that take alternative points of view into account. However, as shown on Table 3, Pattern 2 studies mainly focus on elaborated (TAP-structure) types of argument. This is probably related to the disciplinary influence that TAP has in science (Erduran et al. 2004), and most of Pattern 2 studies, as we will see later on, come from the science field.

LTA Pattern 3: High-structured Deliberation
When deliberation is the major goal-based task enacted by the studies, a different LTA pattern emerges, always under a highly structured dialogic framing, as with Pattern 2. The difference is that Pattern 3 (high-structured deliberation) studies place the weight not on the articulation between theory and evidence (which is presupposed) but on the articulation between different theories, of which only one can be chosen as the 'best explanation'. Examples of this enactment include considering opposing viewpoints to critique and potentially refine ideas (Golanics and Nussbaum 2008) coming to an agreement on the most sensible solution (Cross et al. 2008) and using argumentation to refocus attention away from personal positions and towards the reasons underlying those positions in light of alternatives (Hsu et al. 2015). The distinction between justificatory and explanatory discourse is also evident in this group of studies (e.g., Asterhan et al. 2012;Noroozi et al. 2013;Oliveira et al. 2015), as with Pattern 2. However, among Pattern 3 studies, attention to metalevel processes is more explicit, including knowledge of the formal qualities of single arguments and of argumentative sequences (Noroozi et al. 2013), regulation of meta-cognition (Hsu et al. 2015), acquisition of argumentation norms as a classroom discourse pattern (Yun and Kim 2015), and willingness to disagree (Kim et al. 2007).
Given the focus on deliberation in Pattern 3 studies, we might again expect more explicit attention to 'dialectic' arguments (integrated arguments taking two contrary perspectives into consideration). However, as shown on Table 3, this is not the case. It seems that dialogic rather than dialectic transactivity is highlighted, which also explains the increased emphasis on meta-level processes. This may be because the majority of these studies take place in small groups, as we will see later on in this section; therefore, a great attention to calibrate a variety of perspectives is necessary.

LTA Pattern 4: Dialectic Deliberation
Finally, studies belonging to the fourth pattern (i.e., dialectic deliberation) explicitly define argumentation as deliberative dialogue (e.g., Felton et al. 2015a, b;Garcia-Mila et al. 2013;Villarroel et al. 2016) with deliberation either being 'purely' dialectical, i.e., focusing on the genuine difference in opinions (Asterhan and Schwarz 2009) or as a path towards consensus building (Berland and Lee 2012). From an instructional framing perspective, the only difference between Pattern 4 and Pattern 3 is that in Pattern 4 studies, disagreement is established as a necessary starting point for the dialogue, whereas in Pattern 3 studies, disagreement may or may not emerge during interaction. This is largely because Pattern 4 studies leverage disagreement to drive gains in counter-argumentation (e.g., Asterhan andSchwarz 2009), rebuttals (e.g., Felton 2004;Kuhn et al. 2016b), and argument-counterargument integration (expressed through revisions, concessions, and compromises) (e.g., Felton et al. 2015b;De Vries et al. 2002;Muller-Mirza et al. 2007;Nussbaum and Edwards 2011). This explicit focus on dialectic deliberation, more often framed in one-to-one rather than small-group settings as illustrated below, leads to a greater focus on the quality of arguments-as-products with the significant majority of Pattern 4 studies focusing on dialectic types of arguments (see Table 3).

LTA Fostering Methods
Considering our whole studies' sample (N = 143), the two main methods for fostering LTA were related to (a) the teacher or coach and (b) the task itself. In total, 72 studies (50%) reported that some type of coach-based method was effective in bringing out any type of gains in students' argumentative dialogue, and 77 studies (54%) did so with task-based methods (32 studies used both coach-based and task-based methods). Among the task-based methods, a majority focused either on the instructional task's structure (e.g., a script for interaction) (37 out of 77 studies), or on an instructional technique adopted as part of the class (e.g., Philosophy for Children) (33 out of 77 studies).
In addition, 41 studies (29%) used some type of material scaffold (visual, online, mixed, or other) to ensure or 'boost' the quality of argumentative dialogue, whereas 28 studies (20%) referred to some type of peers' role, either prescribed or enacted during dialogue, as a relevant fostering factor. Though less common than coach-based and task-based methods, peers' role was an important fostering method either as a variable set a priori or as enacted during interaction. Examples of prescribed peers' role are discussion host (Yun and Kim 2015;Zhang et al. 2016), critical audience (Forman and Ford 2014;Gillies and Haynes 2011), and peer coach (Veerman et al. 2000). Examples of enacted peers' role are leader versus helper (Albe 2008), expert versus follower (Cross et al. 2008), and metacognitive questioner (Gillies 2013).
When considering only the studies belonging to one of the four patterns described above, the distribution of fostering methods per study pattern reveals some further insights regarding how different instructional framings come along with different ways of scaffolding dialogue gains. An interesting observation is that the more we move from low-structured sensemaking to high-structured deliberation, the more concrete the teacher's role becomes, from being a dialogue facilitator to an encourager of transactive reasoning, and from being a thinking guide to a challenger and a critical thinker. Also, the instructor's role in dialectic deliberation vanishes, meaning that the focus is not on what the instructor does or does not, but what the students do as result of the learning environment's guidelines. Alongside this shift, the material supports also move from visual materials (like drafts, graphs, sheets) towards highly structured, often computer-supported, collaborative learning environments. Moreover, the richest study patterns in terms of the variety of scaffolding methods used are Patterns 2 (high-structured articulation) and 3 (high-structured deliberation). Figure 2 presents a comprehensive summary of some representative examples of how LTA dialogue is fostered in each study pattern.

Contextual Aspects of LTA Studies
Overall, the four instructional framing patterns described above seem to define argumentative dialogue in different ways and with different purposes. In this section we will focus on RQ2: In what different ways is argumentative dialogue fostered and/or scaffolded in different contexts? We consider 'context' in the following ways, directly relating to the learner characteristics in our MeDOL framework: (a) the dialogue setting, (b) the subject matter, and (c) students' educational grade.

Study Patterns and Dialogue Setting
To test for an association between the four study patterns and the dialogue setting, we again performed Fisher's exact test, which returned a significant result, p < .0001, with a moderate Fig. 2 Selective presentation of fostering methods per study pattern effect size, φc = .545. We can then infer that a first differential contextual aspect of the four study patterns previously identified is the dialogue setting, being: (a) one-to-one, i.e., a peer or dyad of peers arguing 'against' another peer or dyad; (b) small group, i.e., the LTA task relies on student groups to solve/engage with; or (c) whole class, meaning that the teacher guides the dialogue with everyone at a time. Based on analysis of the residuals (Table 4), Pattern 1 studies are mostly associated with whole-class discussions, Pattern 2 and Pattern 3 studies with small-group settings, whereas Pattern 4 studies with one-to-one discussions (as in the case of structured debates).

Study Patterns and Subject Matter
When it comes to the use of a LTA pattern in a specific disciplinary context, we again found a significant association by Fisher's exact test (p < .0001), this time between study pattern and subject matter. The effect size was moderate (φc = .415). An analysis of residuals (Table 5) suggests that, the majority of Pattern 2 studies focus on Science (including Maths) and socio-scientific issues (SSI), Pattern 4 mainly focuses on general interest and scientific topics, and Pattern 1 studies focus more on Language/History.

Study Patterns and Educational Grade
Finally, a test of association between the four study patterns and students' grade level produced a significant result using Fisher's exact test (or approached significance, after a Bonferroni corrected alpha level of .01), p = .031, with a moderate effect size, φ c =.262. As shown on Table 6, Pattern 1 studies were most common at the elementary level, and pattern 4 studies were most common at the university level.
In summary, four study patterns emerged in our sample based on how learning to argue is framed and operationalized as a pedagogical goal: & Low-structured dialogic sensemaking (Pattern 1) is commonly applied to teacher-mediated whole-class discussions with young children in a variety of disciplinary contexts, with teachers' dialogic moves being used as the main scaffold for students. & High-structured dialogic articulation (Pattern 2) is associated with TAP structure arguments in small-group settings, particularly in science inquiry where templates and graphs are used as a primary scaffold for students to construct and compare their scientific explanations. & High-structured dialogic deliberation (Pattern 3) is associated with a high presence of socio-emotional and meta-level processes, applied mostly with secondary school students particularly with science and SSI topics. & Dialectic deliberation (Pattern 4) is associated primarily with the production of integrated dialectic arguments in peer-to-peer discussions about general interest issues among older students (adolescents and adults).

Discussion
Despite extensive research, defining the characteristics of effective argumentative dialogue is an open problem, reflected in the complexity and importance of designing argumentative learning environments 'that work' (Berland and McNeill 2010;Bell and Linn 2000;Clark et al. 2007;Jiménez-Aleixandre 2008). Such an enterprise is relatively simple when the goal of argumentative dialogue is some type of measurable conceptual gains in content learning, or performance on a reading/comprehension test. The same is not true when the goal is to promote advances in argumentation itself, either as a process or an outcome. A common paradox in sociocultural learning emerges: How can learners learn how to argue effectively, when effective engagement in argumentation is a necessary part of such learning? We will address this paradox by referring to two terms commonly used in the literature to refer to effective educational dialogue, namely productivity and constructiveness.
Drawing on Bereiter's ideas, Wells and Arauz (2006) define productive dialogue as one in which 'participants are willing to revise their own opinions as they open-mindedly consider the proposals and arguments of others' and thus 'the common understanding jointly created is superior to that with which the participants started ' (pp. 415-416). Similarly, a dialogue is constructive when it 'literally adds to the (co-)construction or building of somethingmeaning, understanding, solutions to problems and sometimes knowledge', and when 'it generally contributes in some way to cooperative goal-oriented activity' (Baker 1999;pp. 180-181). In other words, from a productive dialogue perspective, what matters is the production of dialogue moves and sequences that may be considered of a 'high' dialogic quality, such as: open questions, elaboration of previous contributions, reasoned discussion of competing viewpoints, linkage and coordination across contributions, and metacognitive engagement with dialogue (Hennessy et al. 2016;Howe et al. 2019). Furthermore, from the perspective of constructive (argumentative) dialogue, the focus is on the construction of new argumentative and/or content knowledge (e.g., Baker 2009;Noroozi et al. 2013), as part of completing a task with a concrete goal, such as solving a complex problem, addressing an ill-defined issue, or making a decision. When such a goal is reached through a careful calibration of ideas and weighing of points of views, we can even talk about 'productive argumentation' (Andriessen and Schwarz 2009). This theoretical tripartite of productive dialogue, constructive argumentative interaction, and productive argumentation is confirmed by our findings, pointing to the richness of approaches within what can be generally referred to as 'learning to argue' (Muller-Mirza and Perret-Clermont 2009;Von Aufschnaiter et al. 2008). What this review further brings to our knowledge is the instructional effectiveness potential of each one of these theoretical paradigms when applied in concrete contexts. Below we will give a summary of the different instructional framings emerged, discussing the affordances and limitations of each.

Instructional Framing Used to Optimize Classroom Discussions
Under this approach, applied by Pattern 1 studies in our sample, sensemaking is the foundational dialogue goal-task, related to grasping content, framing an authentic question, and co-constructing possible responses. Studies that use instructional framing to optimize classroom discussions tend to focus on dialogue quality per se as an indicator of how thinking and reasoning take place. This characterization of dialogue quality includes exploratory talk (as opposed to presentational or recitation talk) (Brown 2016; Molinari and Mameli 2013), dialogic co-construction of knowledge (Mason 1998), interpretive authority (Chisholm and Loretto 2016), or even presence of arguments (Lee and Majors 2003). Although the focus is not directly on the production of more sophisticated argumentative products, this often is a desired outcome. For example, in Larrain et al. (2014), students' justification of counterarguments and rebuttals is the main indicator of the dialogue's productivity, and it is explicitly fostered by teachers' requests for justifications. Similarly, Sutherland (2006) focuses explicitly on students posing higher-order questions and encouraging critical responses, which are considered a Level 5 argument quality in our coding system (see Table 1). This is made possible, again, through the instructor's explicit orientation towards modelling questions.
When it comes to gains in argument-as-process, Pattern 1 studies in our sample did not typically focus on socio-emotional and meta-level processes as outcomes. And yet, at least conceptually, both processes could play an important role in sensemaking. The collective elaboration and engagement with different views, also known as 'relational agency' (Edwards 2011), is a pre-requisite for social knowledge construction. Learners must not only express their own ideas in dialogue, but also interact with others in ways that invite, interpret, and examine views. Commitment to these processes naturally emerges from a growing epistemic awareness and meta-level processing of the dialogic process. These are an essential process in any argumentative learning environment, especially when concrete content learning outcomes are expected, because social agency and epistemic agency are so interrelated that one cannot take place without the other. As Miller et al. (2018) remark, for students to be able to act with epistemic agency in the classroom, soliciting and building on each other's knowledge as a resource for learning is a first step in their participatory sensemaking. Additional research exploring these complex relationships in sensemaking dialogue is warranted.
When it comes to fostering methods and conditions related to this type of LTA instructional framing, a preference towards instructors' roles/moves and instructional techniques is observed (Figure 2). It is, therefore, possible that students' LTA gains, among studies following this framing, are largely due to the effectiveness of the teacher in engaging with students' thinking (Leach and Scott 2002;Murphy et al. 2016).

Instructional Framing Used to Optimize Articulation of (Scientific) Contents
Articulation, the main focus of Pattern 2 studies, commonly corresponds, in our review, to collaborative inquiry, i.e., the process in which students engage in collaborative efforts to advance their shared understandings of the phenomenon or issue at hand (Hakkarainen 2003). The passage from sensemaking (content problematization) to articulation, or from Pattern 1 to Pattern 2 study approaches, is marked by a passage from information seeking and elaboration to critique (Chen et al. 2016) or from knowledge-sharing to knowledge-constructing discourse (Fu et al. 2016). Exploratory talk in its full original sense as both construction and critique (Mercer 1995) is what characterizes the dialogical interactions taking place in Pattern 2 articulation studies. But how is this balance between construction and critique achieved? In other words, how can students learn to argue effectively when the focus is on advancing knowledge? One might say that this is possible through transactive reasoning focusing on counterarguments and rebuttals. However, this was the case only in very few studies in our sample (e.g., Ford 2012; Gillies 2016), as the majority of Pattern 2 studies focused on the TAP structure as an indicator of constructive argumentation. This may be because of the focus of scientific inquiry on the construction of scientific explanations, and the TAP structure gives teachers and researchers a (more or less) clear idea of what a scientific explanation looks like (Erduran et al. 2004).
Productive dialogue, for studies focusing on articulation/collaborative inquiry as their main task, is commonly part of interactions where students navigate and negotiate their understandings of phenomena towards more coherent explanations (Baker 1999;Chen et al. 2019). For these moments of collaboration, understood as deep engagement with each other's ideas, to emerge, both argument-as-products and arguments-as-process are necessary: the more constructive students become with their own contributions, the more productive the interaction with each other's contributions becomes (Chi and Menekse 2015). However, what we observe in Pattern 2 studies is a focus on either high-level (4 & 5) arguments-as-products alone, or on a combination of medium-level arguments (2 & 3) with some type of relevant socio-emotional or metalevel processing. We consider this a rich area for inquiry to fill a gap in literature on articulation. As Chen et al. (2019) argue, students' epistemic understanding of argument, especially its plausible and 'uncertain' nature, cannot be separated from their social negotiation processes. What material and visual scaffolds usually do is to reduce such uncertainty, orienting students towards the construction of a theory or solution. Peers' and instructor's role in maintaining uncertainty, through for example the use of critical questions, would be an asset for this type of studies, as it would increase dialogical transactivity around plausible scientific explanations.

Instructional Framing Used to Optimize the Search for the Best Explanation
Finally, deliberation whether it is framed as small-group interaction (Pattern 3 studies) or one-on-one debates (Pattern 4 studies) focuses on the production of transactive arguments. This includes studies focusing on prompting students to co-construct meanings without necessarily critically contrasting these meanings with each other. In such cases, the learning environment serves as a context of conceptual convergence, understood as a common focus on the construction of shared understanding (Oliveira and Sadler 2008). When this focus on collaboration rather than persuasion also forms an explicit part of the instructional goals for deliberative dialogue, it is often the case that dialectically transactive moves (e.g., claim revision, articulating opposing positions, argument-counterargument integration) emerge in students' discourse (Berland and Lee 2012;Nussbaum 2002;Nussbaum and Edwards 2011;Vogel et al. 2016). This is explained by the principles of coalescent argumentation (Gilbert 2013) according to which collaboration and confrontation are both aspects of a balanced process of critical questioning and coalescing arguments.
Nonetheless, it is also often the case that argumentative dialogue is framed as a process of committing to a position and proving its validity against an opposing position. However, even in this context of adversarial argumentation, a focus on individual reflection on the arguments produced during interaction is often present, either as part of the instructional prompts or as part of the computer-supported collaborative learning environment in which argumentation takes place. This finding is in line with recent recommendations for more research on the role and nature of reflection as a mediating process in students' learning to argue (Iordanou and Constantinou 2014). That said, when students are asked to deliberate in a context of highly divergent positions, the focus must not be on divergence per se, but on how and why these positions differ from each other in terms of their evidence quality and relevance (Macagno 2016(Macagno , 2019 and how argumentative talk is productively employed from part of the students as required or prompted by the activity design (Schwarz 2009). That latter is not always guaranteed, calling for additional research into the types of instructional prompts and dialogic moves used to support student interaction. This might include, for example, further research into the metacognitive questions asked by teachers, as they move from group to group or from dyad to dyad, which is an aspect studied in depth by the Pattern 1 studies, mostly focusing on whole-group discussions. In addition to the mediatory teacher's role, peers' role can also be further looked at, as recent research suggests that placing the focus on affordances for peer-to-peer counter-argumentation and rebuttal using relevant evidence is an effective strategy for learning to argue (see, for example, Larrain et al. 2019).

Study Limitations
As with meta-analyses (Glass 1976), the integrative review bears the limitation of shifting away from the original units of analysis in the studies reviewed to treating the studies themselves as the unit of analysis. Doing so runs the risk of collapsing disparate findings across settings in the interest of seeing larger patterns in the literature. That being said, we have mitigated this problem by focusing not on the conclusions drawn by each study, but instead on the approach taken by the researchers. Nonetheless, we recognize (per Jackson 1980) that we have had to make inferences about how researchers frame learning to argue, rather than drawing on explicit statements made by the authors themselves (particularly in the field of educational dialogue, where learning to argue is not necessarily positioned as the goal of dialogue).
A second limitation is that we cannot use our findings to infer which of the studies' characteristics caused the results reported. Whatever statistical results were reported must be seen as a meta-analytical approach of associations of study characteristics coded a posteriori, and not expressing any causal relationship between units of analysis originally used in the studies we reviewed. A final limitation regards the number and type of studies selected to be reviewed. As Jackson (1980) again would point out, the selected studies of a review should be considered only a sample of the phenomenon being studied. Though we have followed recommended practices in sampling from the literature, selecting studies according to their relevance to the phenomenon under investigation (i.e., learning to argue), we recognize that we have not addressed the whole population of studies in the fields of educational dialogue and argumentation, as that would be beyond the scope of this paper and would preclude a focused analysis of the literature.

Conclusion
Constructing learning environments that promote learning to argue (LTA) through dialogue has been characterized as a complex enterprise (Clark et al. 2007;Jiménez-Aleixandre 2008), without sufficiently addressing the reasons for this complexity. We focus on instructional framing as a way to look at the LTA literature, perceiving as such: the methods and approaches implemented by researchers to frame educational dialogue, the dialogue goals pursued as part of the LTA activity, the noted gains in terms of LTA, and the learners' characteristics. Our analysis of the reviewed studies revealed a continuum in the LTA literature, with four different concentrations in empirical studies, namely: engaging in low-structured sensemaking, engaging in high-structured articulation, engaging in high-structured deliberation, and engaging in dialectic deliberation. Each research focus has its own affordances and limitations as discussed above. Interestingly enough, what emerges as a limitation for one trend of research is covered by another, pointing out to the complementarity of existing instructional approaches aiming, either directly or indirectly, at learning to argue.
An implication of the above is that when it comes to teaching students how to argue, all four approaches need to be considered to fully leverage the benefits of engaging in argumentative dialogue. The complementary patterns we have identified clears the way for a better understanding of pedagogical content knowledge in argumentative dialogue, in the interest of designing more effective and purposeful dialogue-based and dialogue-oriented learning environments.
Data Availability Data will be available upon request.

Declarations
Conflict of Interest The authors declare no competing interests.
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