Introduction

Differentiation has become a central concept in contemporary language education, particularly in contexts characterized by learner diversity, mixed-ability groups, and varied motivational profiles. In English language teaching (ELT), differentiation responds to the pedagogical challenge of ensuring that all learners, regardless of background, proficiency, or learning preferences, can meaningfully engage with instruction and achieve shared learning objectives.

This essay, my 519th publication in this blog, explores the concept of differentiation through the lens of TeachingEnglish: Managing learners and resources, a course offered by the British Council, with particular attention to Module 2, Unit 1: Understanding differentiation. Drawing on the British Council’s definitions, Carol Ann Tomlinson’s theoretical framework, and practitioner perspectives, the essay also integrates reflective insights from my own professional practice. The discussion argues that differentiation is not merely a set of techniques, but rather a pedagogical mindset grounded in respect for learner diversity and a commitment to maximizing each learner’s potential.

Defining Differentiation in Language Teaching

According to the British Council (n.d.), differentiation occurs when “a teacher adapts some parts of the task, instructions, lesson or activity to suit the needs of the particular learners, to ensure all learners are included in the lesson.” This definition highlights inclusion as the primary goal of differentiated instruction. Importantly, differentiation does not imply lowering standards or fragmenting learning objectives. On the contrary, “all learners should achieve the same aim, but they may do this in different ways” (British Council, n.d.). For example, learners may demonstrate comprehension through writing, drawing, or oral explanations, depending on their linguistics or cognitive strengths and learning preferences.

In a differentiated lesson, teachers take into account learners’ levels, interests, and needs. Some learners may extend beyond the core objective, while others may achieve it at a more basic level, such as responding with one-word answers instead of complete sentences. This flexible approach recognizes variability as a natural condition of classrooms rather than an exception to be managed.

Differentiation as a Way of Thinking: Tomlinson’s Framework

Carol Ann Tomlinson’s work provides a foundational theoretical perspective on differentiation. In her influential article, Tomlinson (2000) emphasizes that differentiation is not a formula or a discrete instructional strategy. As she asserts, “what we call differentiation is not a recipe for teaching… It is a way of thinking about teaching and learning. It is a philosophy.” This philosophy is grounded in a set of beliefs about learners, learning, and the role of schools.

Tomlinson’s (2000) first belief recognizes that students of the same age differ significantly in “readiness to learn, interests, styles of learning, experiences, and life circumstances.” These differences are not trivial; rather, they “make a major impact on what students need to learn, the pace at which they need to learn it, and the support they need from teachers and others” (Tomlinson, 2000). Learning, therefore, is most effective when supportive adults push learners slightly beyond what they can do independently, echoing Vygotskian notions of mediated learning.

Further, Tomlinson (2000) argues that learning is enhanced when students can connect curricular content to their own interests and life experiences, when learning opportunities feel natural, and when classrooms foster a sense of community in which learners feel “significant and respected.” Ultimately, she contends that “the central job of schools is to maximize the capacity of each student” (Tomlinson, 2000). The British Council’s paraphrased version of these beliefs reinforces their practical relevance by foregrounding learner significance, respect, and capacity-building as core educational values.

Learner Differences in the Language Classroom

Understanding learner differences is a prerequisite for effective differentiation. Reflecting on this issue, I have argued that although learners may be grouped under the same proficiency level, “there are many differences when two learners are compared” (Acuña, 2026). Learners vary in cognitive load, cognitive capacity, prior knowledge, motivation, and the degree of scaffolding they require. No two language learners occupy the same zone of current development or zone of proximal development at any given time (Acuña, 2026).

These observations align with practitioner insights shared in the British Council course. Stephen Sharpe, a teacher in Tunisia, notes that learners differ in their motivation, reasons for learning, and opportunities to practice the language. Lucy Widdowson, teaching in England, emphasizes age-related differences, learning pace, interests, and learner attitudes, including confidence and willingness to participate. Similarly, Alister Widdowson highlights differences in background, experience, aptitude, and specific language needs, concluding that “we can’t treat every child or every student the same” if we want all learners to progress.

Collectively, these perspectives point to a wide range of factors influencing learner diversity, including socio-economic background, cultural factors, learning preferences, attitudes toward the teacher, and aptitude for particular skills. Differentiation, therefore, emerges as a pedagogical necessity rather than an optional enhancement.

How Teachers Differentiate in Practice

Differentiation can be operationalized in multiple ways within the language classroom. From my own practice, I rely on Kolb’s experiential learning cycle to identify learner preferences, recognizing that classes often include “feelers, thinkers, doers, and watchers” (Acuña, 2026). Awareness of these learner types allows for more effective task design, increased participation, and strategic pairing or grouping of students.

Practitioner accounts from the British Council further illustrate practical differentiation strategies. Sharpe suggests varying lesson content and task types to address individual needs. Lucy Widdowson focuses on differentiating instructions so that “different learning paths will lead to the same learning outcome,” while continuously adjusting lessons based on learner responses. Alister Widdowson emphasizes interaction patterns, such as pairing stronger and weaker students, grouping learners by level, adjusting task difficulty, and allowing flexible timing.

These strategies demonstrate that differentiation can occur through content, process, interaction, and pacing, all while maintaining common learning goals.

Why Differentiation Matters

The rationale for differentiation is strongly articulated by both theory and practice. Sharpe argues that differentiation ensures all learners have access to lesson content and experience success (British Council, n.d.). Lucy Widdowson adds that it allows learners to demonstrate what they know, reach their full potential, and develop motivation and confidence, noting that “one size does not fit all” (British Council, n.d.). Alister Widdowson goes even further, asserting that “we can’t really teach without it,” as differentiation enables learners to progress at their own pace and measure their development (British Council, n.d.).

From my perspective, the ultimate objective of differentiation is to ensure that “all learners have achieved learning objectives by the end of the class” (Acuña, 2026). In communicative language teaching contexts, this means that learners should be able to use target vocabulary and structures in tasks that reflect real-life communication (Acuña, 2026). When learners can successfully perform such tasks, they are able to self-assess their level of assimilation and practical language use (Acuña, 2026).

Differentiation by Resource Use

Resources play a crucial role in supporting differentiation. Reflecting on my synchronous virtual classes, I note that one of the most valuable resources is “the other learners,” as peer interaction maximizes opportunities for practice (Acuña, 2026). Digital presentations help structure lessons, while exam-practice websites provide additional individualized practice aligned with learner goals.

The way resources are used can significantly affect learners. Based on learner success rates and course attrition, I perceive a positive impact, though I also acknowledge the need for greater variety to sustain attention and interest. Using diverse resources supports differentiation by motivating learners and emphasizing language use over rote study. In adult education contexts, differences between young adults and working adults are particularly salient, as professional needs and life experiences strongly shape engagement and outcomes.

The British Council’s (n.d.) teaching tip encapsulates this idea succinctly: teachers are “most likely to meet the needs of a wider range of learners if [they] use a wide range of resources.” Inviting learners to contribute resources or create their own materials can further enhance ownership and differentiation.

Conclusion

Differentiation in language teaching is best understood not as an add-on strategy, but as a pedagogical philosophy rooted in learner-centeredness, inclusivity, and respect for diversity. The British Council’s framework, Tomlinson’s theoretical insights, practitioner testimonies, and reflective classroom experience collectively underscore that learners differ in meaningful ways that directly impact learning.

Differentiation responds to this reality by offering flexible pathways toward shared learning goals. When thoughtfully implemented through instructional design, interaction patterns, and resource use, differentiation enables teachers to push learners toward their zone of proximal development while maximizing each learner’s capacity. In this sense, differentiation is not simply good practice; it is essential practice in effective language education.

José de Alencar’s theatrical play Mãe (“Mother”) occupies a distinctive position within nineteenth-century Brazilian literature. While Alencar is frequently associated with Indianist novels and the project of national romanticism, Mãe reveals his engagement with social melodrama and moral realism, particularly in relation to family, class hierarchy, and slavery. First staged in 1860, the play dramatizes the tragic consequences of social prejudice through the figure of Joana, an enslaved woman who suppresses her maternal identity to preserve her son’s social status and future. Through its plot structure, symbolic characterization, and ideological tension, Mãe exposes the contradictions of a society of yesteryear that venerates motherhood while denying its humanity to enslaved women. This essay (my 518th post in Reflective Online Teaching) analyzes the plot, central and secondary characters, and symbolic framework of Mãe, drawing on Romantic melodrama and realist social critique to demonstrate how Alencar transforms private sacrifice into a collective moral indictment.

Plot Structure and Moral Progression

Alencar’s Mãe follows a melodramatic structure consistent with what Peter Brooks (1976) terms the “moral legibility” of melodrama, in which ethical conflict is heightened to render injustice visible. The plot centers on Jorge, a young man striving for social respectability, and Joana, his enslaved mother, whose maternity must remain hidden for him to circulate freely within a rigidly stratified society. The concealment of Joana’s identity functions as the play’s primary dramatic tension, shaping both its emotional trajectory and its ethical stakes.

The author delays the revelation of Joana’s maternity, allowing the audience to experience the cost of silence before its consequences emerge. This narrative strategy aligns with Antonio Candido’s (1975) observation that Alencar often privileges gradual moral exposure over sudden revelation though the spectator or the reader already knows the character’s internal drama. The climax of the play occurs not through confrontation but through erasure: Joana chooses death rather than disclosure, preserving her son’s social standing at the expense of her own existence. While this resolution conforms to Romantic tragedy, it simultaneously gestures toward realist critique. As Roberto Schwarz (2000) argues, Brazilian literary narratives of this period frequently expose how personal virtue is mobilized to stabilize unjust social structures.

Joana and the Symbolism of Silenced Motherhood

Joana is the ethical and symbolic core of Mãe. Although socially marginalized, this characters embodies the play’s highest moral value: unconditional maternal love. Her motherhood, however, is both biologically undeniable and socially inadmissible. This contradiction situates Joana within what Gilbert and Gubar (1979) describe as the literary tradition of silenced women whose virtue is expressed through self-negation rather than agency.

Symbolically, Joana represents the enslaved mother whose humanity must remain invisible for the social harmony of her son to persist. Alencar avoids portraying her as rebellious; instead, her dignity lies in endurance and restraint. This aligns with Romantic idealizations of moral purity, yet it also exposes their limits. As Alfredo Bosi (1992) notes, Alencar often elevates individual ethics while leaving oppressive systems intact, creating a dissonance between moral sentiment and social transformation. Joana’s death thus functions not as redemption but as indictment. Her disappearance confirms Roland Barthes’s (1972) notion of characters as cultural signs: Joana signifies the cost of maintaining social illusion.

Jorge and the Illusion of Merit

Jorge embodies the fragile ideal of social merit. Unlike Romantic heroes defined by moral autonomy, Jorge’s respectability depends on his ignorance regarding who his mother was or is. His social position is made possible by the suppression of his origins, revealing what Terry Eagleton (1996) describes as ideology’s capacity to conceal its own foundations. Jorge’s suffering upon learning the truth does not equal Joana’s loss; rather, it underscores the asymmetry of sacrifice within hierarchical systems.

Jorge’s trajectory illustrates Candido’s (1987) claim that Brazilian Romanticism often dramatizes personal conflicts that mirror collective moral failures people in different social sphere avoid discussing or making visible. His apparent mobility exposes the illusion of merit in a society structured by lineage and race. He does not actively oppress Joana, yet he benefits from her erasure, making him a passive participant in systemic injustice.

Secondary Characters as Ideological Agents

While Joana and Jorge anchor the emotional core of Mãe, secondary characters such as Dr. Lima, Peixoto, Sr. Gomes, and Elisa function as ideological agents who sustain the social order the tragedy depends upon and describes for the reader or drama viewer. Rather than serving as antagonists, they embody the mechanisms through which injustice is normalized in that period of history.

Dr. Lima represents institutional rationality and enlightened authority. Educated and compassionate, he recognizes suffering but never challenges its causes. His interventions are pragmatic rather than transformative, exemplifying what Eagleton (1996) identifies as bourgeois humanism: ethical concern without structural critique. Dr. Lima reassures the audience and the readers that the social system he is part of is reasonable and fair, even as it destroys Joana.

Peixoto, by contrast, symbolizes utilitarian adaptation. He understands the social rules governing legitimacy and navigates them opportunistically. His moral flexibility reveals how injustice persists not through cruelty but through convenience. Peixoto exposes the transactional logic underlying social survival in a slaveholding society.

Sr. Gomes embodies patriarchal law and the authority of appearances. His judgments are rooted in lineage, honor, and social legitimacy rather than ethical substance. He functions as a gatekeeper of respectability, illustrating why Joana’s truth must remain unspeakable. For Sr. Gomes, morality is genealogical, not humane. Sr. Gomes appears as a puppet of the enslaving system all the characters live in.

Elisa represents conditional love shaped by social conformity. While affectionate and sincere, her feelings for Jorge are constrained by class ideology. Elisa reveals how women may simultaneously suffer under and reinforce patriarchal norms. Her character demonstrates that even romantic affection operates within rigid social boundaries, reinforcing Lukács’s (1971) concept of “typical characters” whose private lives reflect broader social contradictions.

Together, these characters form an ideological chorus: Dr. Lima rationalizes, Peixoto negotiates, Sr. Gomes legitimizes, and Elisa normalizes. Joana’s death is not caused by a single villain but by a system in which everyone fulfills their role.

Maternal Sacrifice and Social Critique

The title Mãe foregrounds motherhood as both sacred and problematic. Alencar elevates maternal love while exposing how society denies full motherhood to enslaved women. This paradox aligns with Adrienne Rich’s (1976) distinction between motherhood as institution and motherhood as lived experience. Joana lives motherhood as devotion and loss, while society instrumentalizes it to preserve order.

Silence emerges as a central motif. Joana’s silence protects Jorge but annihilates her identity, suggesting that social harmony is achieved through moral erasure. The play thus transforms melodrama into critique, revealing the ethical cost of maintaining appearances.

Conclusion

Mãe stands as one of José de Alencar’s most ethically complex dramatic works. Through its melodramatic structure, symbolic characterization, and ideological tension, the play exposes the contradictions of nineteenth-century Brazilian society regarding slavery, class, and motherhood. Joana’s sacrifice reveals the human cost of social illusion, while Jorge and the secondary characters demonstrate how injustice is sustained through normalization rather than cruelty. Positioned between Romantic sentiment and realist critique, Mãe compels readers and audiences to confront the moral foundations of respectability itself.

San José, Costa Rica

Saturday, January 24, 2026

📚 References

Barthes, R. (1972). Mythologies. Hill and Wang.

Bosi, A. (1992). História concisa da literatura brasileira. Cultrix.
Brooks, P. (1976). The melodramatic imagination. Yale University Press.
Candido, A. (1975). Formação da literatura brasileira. Martins Fontes.
Candido, A. (1987). Literature and society. Edusp.
Eagleton, T. (1996). Literary theory: An introduction. Blackwell.
Gilbert, S. M., & Gubar, S. (1979). The madwoman in the attic. Yale University Press.
Lukács, G. (1971). The theory of the novel. MIT Press.
Rich, A. (1976). Of woman born. W. W. Norton.
Schwarz, R. (2000). Misplaced ideas. Verso.

Introduction

Group work and mixed-ability instruction are now central to communicative language teaching (CLT), yet they remain among the most demanding aspects of classroom management. While collaborative learning promises increased interaction, learner autonomy, and meaningful language use, it also generates challenges related to participation, conflict, learner behavior, and uneven contribution. Module 1, Unit 3 of the British Council’s TeachingEnglish: Managing learners and resources foregrounds these tensions through authentic teacher scenarios and practical recommendations.

This essay, my 517^th post in my reflective journaling blog, integrates those insights with established ELT theory and my own professional reflections as Jonathan Acuña. Drawing on scholars such as Harmer, Scrivener, Dörnyei, Johnson and Johnson, and Vygotsky, the paper argues that effective management of group dynamics and mixed-ability classes requires principled task design, explicit role allocation, socio-affective awareness, and a theoretically informed understanding of learner diversity.

Group Work, Task Structure, and Off-Task Behavior

One of the most common problems in group work is learners drifting into off-task conversation. As described in Teacher 1’s scenario in this British Council’s course, unfocused interaction often results from unclear task design rather than learner indiscipline. Scrivener (2011) emphasizes that “many discipline problems are actually planning problems” (p. 85). When learners do not fully understand what they are expected to produce, they naturally fill the gap with social talk.

The British Council’s recommendation that tasks have a clear structure, visible instructions, and a defined outcome aligns with task-based learning principles. Ellis (2003) defines a pedagogical task as one in which “the primary focus is on meaning” and where learners work toward a clearly defined outcome (p. 9). Without that outcome, learner attention dissipates.

In addressing off-task behavior during group work, I have come to reflects on the tendency of high-performing learners to disengage in unconventional ways. As I have noted, “These unengaged learners can be top performers who may want to ‘shine in class’ differently, so these students can help you demonstrate what learners have to do during the activity” (Acuña 2026). This observation aligns with Harmer’s (2007) assertion that learner disengagement often signals a need for increased responsibility rather than stricter control.

Conflict, Disagreement, and the Social Nature of Learning

Conflicts arising during group work are often perceived as disruptive. Similarly, when discussing classroom conflict, I have always emphasized the inevitability of disagreement in collaborative learning contexts: “Where there are tasks to be performed in a language classroom, we are to have disagreements” (Acuña 2026). From my practitioner’s +30-year experience in the classroom, respect must be explicitly reinforced through classroom norms and recurring reminders, a stance consistent with Dörnyei and Murphey’s (2003) emphasis on establishing a psychologically safe learning environment. However, sociocultural theory reframes disagreement as a potentially constructive force. Vygotsky (1978) famously argued that learning is fundamentally social, stating that “every function in the child’s cultural development appears twice: first, on the social level, and later, on the individual level” (p. 57). From this perspective, disagreement can serve as a catalyst for cognitive development.

Johnson and Johnson (1995), in their work on cooperative learning, assert that “controversy among ideas promotes higher achievement, greater perspective-taking, and more frequent use of higher-level reasoning strategies” (p. 262). This supports the British Council’s recommendation to encourage learners to “agree to disagree” and reflect on how conflict can benefit task outcomes.

Regarding post-conflict group dynamics, my highlight in this area is that the teacher’s role is to mediate beyond linguistic instruction, stating that “as the class administrators and owners, we need to remind our students that in real life… it is always a good idea to find solutions, even with the help of another person” (Acuña 2026). This perspective situates the teacher as a facilitator of social learning, echoing Vygotsky’s (1978) view of learning as inherently social and dialogic. Establishing group contracts reflects what Dörnyei and Murphey (2003) describe as creating “a psychologically safe classroom climate” (p. 72). Such norms reduce the likelihood that conflict becomes personal and help learners recover more easily after disagreements.

Unequal Participation and Role Assignment

Many ELT teachers highlight a persistent issue in group work: unequal participation. Research consistently shows that without structured accountability; group work can lead to social loafing. Johnson and Johnson (1999) stress that effective cooperative learning requires “individual accountability,” ensuring that “each group member is responsible for contributing” (p. 68). Unequal participation is one of those areas that I have also addressed through my participations in teacher conferences, my practitioner insight, drawn from prior TESOL training has taught me that “Assigning the spokesperson role to students who usually struggle forces meaningful engagement and accountability” (Acuña 2026). This strategy operationalizes Johnson and Johnson’s (1999) principle of individual accountability within cooperative learning structures.

The British Council’s emphasis on assigning roles directly reflects this principle. Harmer (2007) notes that roles such as chair, note-taker, and spokesperson “give students a clear reason to participate and a clear understanding of what participation looks like” (p. 166). In my own teaching, assigning the spokesperson role to quieter or weaker learners has proven particularly effective. This practice resonates with Vygotsky’s (1978) concept of the Zone of Proximal Development, where learners perform beyond their current competence with appropriate support.

Monitoring role fulfillment further reinforces accountability. Scrivener (2011) argues that teachers should “listen actively to group work not to control it, but to diagnose learning needs” (p. 98). This diagnostic stance transforms monitoring into a formative, rather than punitive, practice. From my own perspective, this is a way to scaffold learners to have them achieve communication aims and learning objectives.

Managing Learner Behavior and Classroom Roles

Learner behavior cannot be separated from social identity and classroom roles. The British Council’s list of challenging roles, such as the joker or withdrawer, reflects what Dörnyei (2001) describes as learners’ attempts to “negotiate their position within the group” (p. 43). These behaviors often mask deeper needs for recognition, security, or autonomy.

In online university contexts, behavioral management is further complicated by institutional rules. My reflection on enforcing camera policies illustrates the importance of aligning classroom management with institutional frameworks. In relation to learner behavior in online contexts, a policy-informed stance grounded in institutional responsibility is necessary: “This type of behavior is not acceptable and, based on the Student Handbook, students who persist will be considered absent” (Acuña 2026). This institutional approach where I work reflects Harmer’s (2007) argument that effective classroom management depends on a balance between empathy and clearly articulated authority. Harmer (2007) argues that effective teachers balance empathy with authority, noting that “students expect teachers to lead, not abdicate responsibility” (p. 35).

For serious behaviors such as bullying, private intervention is essential. Dörnyei and Murphey (2003) warn that public confrontation can reinforce negative behavior by providing attention. Conversely, silent or withdrawn learners require a supportive approach. As Scrivener (2011) observes, “silence does not necessarily mean disengagement” (p. 67). Offering alternative participation modes acknowledges learner differences without forcing conformity.

Mixed-Ability Classes and Learner Diversity

A foundational premise stated by the British Council is that all classes are mixed-ability classes. This view aligns with contemporary SLA research, which rejects simplistic distinctions between “fast” and “slow” learners. Dörnyei (2005) emphasizes that learner differences stem from a complex interaction of cognitive, affective, and contextual factors, stating that “motivation does not exist in a vacuum but is dynamically shaped by learning environments” (p. 65).

Finally, when reflecting on mixed-ability classes, I have identified a constellation of learner variables including “cognitive load, motivation, study habits, life experience, and work experience” (Acuña 2026), reinforcing Dörnyei’s (2005) claim that learner differences are multidimensional and dynamic rather than reducible to proficiency alone, which closely mirror the British Council’s expanded list. Tomlinson (2014), writing on differentiation, argues that effective teachers “proactively plan varied ways to access content, process ideas, and demonstrate learning” (p. 18). Providing optional extension tasks and choice-based activities allows stronger learners to remain challenged without disadvantaging others.

Factors contributing to being different

personality	age	gender	memory
learning preference	language proficiency	study habits	reasons for learning
preferences for methodology	speeds of working and learning	boredom limits	degree of application and distraction

Taken from the British Council’s course page

https://open.teachingenglish.org.uk/Team/UserProgrammeDetails/676892

Regularly changing groupings further supports social cohesion. Johnson and Johnson (1999) note that rotating groups helps learners develop trust and reduces fixed hierarchies. Encouraging learner autonomy, meanwhile, reflects Holec’s (1981) assertion that autonomy is “the ability to take charge of one’s own learning” (p. 3), a skill essential in mixed-ability contexts.

Conclusion

Managing group dynamics and mixed-ability classes requires more than classroom intuition; it demands theoretically informed decision-making. The British Council’s practical guidance, when viewed through the lens of ELT theory, reveals that challenges such as off-task behavior, conflict, unequal participation, and learner diversity are not failures of group work but inherent features of social learning. By grounding classroom management in principles of cooperative learning, sociocultural theory, motivation research, and differentiation, teachers can transform these challenges into opportunities for deeper engagement. As both research and reflective practice suggest, successful group work depends not on controlling learners, but on designing conditions in which meaningful collaboration can flourish.

San José, Costa Rica

Saturday, January 24, 2026

📚 References

Acuña, J. (January 2026). Professional reflections on group dynamics and mixed-ability instruction. Unpublished reflective coursework for TeachingEnglish: Managing learners and resources, British Council.

British Council. (n.d.). TeachingEnglish: Managing learners and resources. https://open.teachingenglish.org.uk/Team/UserProgrammeDetails/676892

Dörnyei, Z. (2001). Motivational strategies in the language classroom. Cambridge University Press.

Dörnyei, Z. (2005). The psychology of the language learner. Lawrence Erlbaum.

Dörnyei, Z., & Murphey, T. (2003). Group dynamics in the language classroom. Cambridge University Press.

Ellis, R. (2003). Task-based language learning and teaching. Oxford University Press.

Harmer, J. (2007). How to teach English (2nd ed.). Longman.

Holec, H. (1981). Autonomy and foreign language learning. Pergamon.

Johnson, D. W., & Johnson, R. T. (1995). Creative controversy. Interaction Book Company.

Johnson, D. W., & Johnson, R. T. (1999). Learning together and alone (5th ed.). Allyn & Bacon.

Scrivener, J. (2011). Learning teaching (3rd ed.). Macmillan.

Tomlinson, C. A. (2014). The differentiated classroom (2nd ed.). ASCD.

Vygotsky, L. S. (1978). Mind in society. Harvard University Press.