The second chapter of this volume focusses on crowds, both conceptually and historically. The study of crowd influence has waxed and waned over the years and has seen a resurgence of interest in topics such as identity-based social movements, street action and social media. The chapter traces this line of inquiry to the mass psychology of LeBon and Tarde, who conceived of crowds as a powerful social force that compromises Rationality and Civilisation and leads to a 'mass society' dominated by charismatic leaders. Tarde’s laws of imitation extended this inquiry of physical crowds in public spaces to that of distributed public opinion of news readers with a shared focus of attention. These notions have corollaries with contemporary theories of agenda setting, collective attention cycles, crowd sourcing and intelligence, memes and viral beliefs, stock market bubbles and social media dynamics. Much of theory of crowds oscillates between positive and negative moral assessments. The chapter concludes by considering the role of social identification in the dynamics of crowds which distributes human cognition among individual actors and determines the relationship with the leader.

Chapter 10 offers a theoretical integration of the various social influence modalities discussed in previous chapters. It starts by examining the historical evolution of common sense in processes of intersubjectivity and inter-objectivity; social influences are the mechanisms that regulate the normalisation, assimilation and accommodation of new ideas and practices. The chapter elaborates the cyclone model of social influence that integrates these three mechanisms in a dynamic and underdetermined process of social change. The chapter summarises the key tenets of the various modalities of social influence in a Periodic Table of Social Influence. The Periodic Table identifies modalities and their properties in the modes of intersubjective and inter-objective interaction, namely face-to-face, mass mediation and designed artefacts. This Periodic Table of Social Influence will support and catalyse further empirical scholarship and investigations concerning social influence that remain highly pertinent in current society.

The final chapter of this volume provides several points of further theoretical elaborations, which, important for our overall argument, would have unduly cluttered the various chapters. It starts by considering how challenges to common sense arise from various types of dissent or deviance including children, homecomers, newcomers, strangers, foreigners, robots or aliens. It proceeds to discuss why and how object-relations and 'inter-objectivity' thought, noted by various scholars, have not received sufficient attention in psychological scholarship and certainly not in relation to influence by artefacts. The chapter lays out the theoretical foundations for such a broadening of scope. The chapter then proceeds to discuss the historically curious dominance of dual-process models over single-process alternatives. The excursions conclude by revisiting the debates concerning the authority of science in Milgram's obedience studies in light of a broader understanding of autonomy, tyranny, argumentation, legality and violence.

Chapter 7 deals with the most pressing and most prominent social influence in our time, persuasion. The modality of persuasion is oft considered as the epitome of social influence processes with a long past of rhetoric analysis, and a short history of experimental demonstration of effects arising from speaker, message or audience characteristics. The chapter starts by reviewing the moderator variables of persuasion initiated by the Yale Programme. This is followed by considering mainstream dual-process theories that investigated fast or slow, hot or cold cognitive processes resulting in successful persuasion. Following this mainstream overture, the chapter reviews studies of forced and non-forced compliance that precipitate conviction by cognitive dissonance. The chapter ends with reviewing lay epistemic theory and the unimodal of persuasion, making the case for argumentation processes that form attitudes and the appraisal of behavioural inclinations beyond the exercise of mere message tactics of a box of tricks. This leads us to consider the necessary insights into the common ground and the moral community of speaker and audience as a precondition of successful persuasion.

Chapter 3 reviews leadership as a modality of social influence. It starts by reviewing the personality approach to leadership that has predominated in psychological research over the years. This approach focusses on the identification of personality traits, such as charisma, performed in the crowd situation; a trait that successful leaders have acquired in an unclear way. This is juxtaposed by the situational approach to leadership; effective leadership is contingent on particular situations which variably call for different matching traits. Both theories are critiqued in light of normative models of leadership which account for the sticky resilience of dictatorships in various countries around the world even in the face of opportunities for instituting or restituting democracy. The chapter closes with the social identity approach to leadership and paternalism, arguing that effective leadership is contingent on the interplay between leaders and the consent of followers.

The opening chapter charts the way from initial concerns with unruly crowds to contemporary social movements. It locates various modalities of social influence within interactive processes and different modes of communication. Social influence must be analysed in relation to a shifting common sense in line with aspirations of individuals or groups. The chapter steps back from an 'empiricist' treatment of social influence that has predominated in the field, and clarifies three conditions of possibility. Firstly, social influence is non-violent. Social influence seeks to institute claims about the world 'rhetorically', without the violence that turns might into right. Secondly, a functioning public sphere, and less the systems of markets and kinship, is the natural place of social influence. This, however, requires a reciprocal orientation before actors can seek to further their own interests. Thirdly, individual differences of citizen competences condition the prevailing social influences in a society. The chapter concludes with an overview of the chapters on the various modalities of social influence that have been investigated to date.

Chapter 9 examines a second necessary extension of the analysis of social influence to a consideration of the effects of designed artefacts in social relations. The chapter starts with an elaboration of the notion of inter-objectivity: designed hardware permeates human social relations as infrastructure, tools, gadgets and instruments. How is different hardware used to implement modalities of social influence? Crowds have historically used barricades to enhance their power. People easily recognise the fait accompli, for example as a wall, installed in a collective effort of construction. Such installations provide boundaries and parameters of attitudes and behaviour afforded by design, but do so without prior consent. Legitimation is achieved post-hoc by cognitive dissonance in analogy to forced-compliance. Resistance to such faits accompli is introduced as a hitherto unrecognised modality of social influence. It functions to evaluate and to redesign hardware and systems in ways that correct the initial designs; resistance potentially innovates on the 'innovation'.

Chapter 6 considers the most controversial topics in the study of social influence, obedience to authority. The chapter reviews empirical findings concerning obedience in children. These demonstrate how children adopt a complex cognitive assessment of obedience in everyday life. This is countered by what are seemingly more rudimentary processes demonstrated by adults in one of psychology’s best known experiments: Milgram’s obedience demonstrations. The chapter goes on to examine the social identity account of obedience following a review of the Utrecht studies. The latter replicated Milgram’s installation in an ecologically more valid set-up using mediated expression of violence. The chapter concludes by arguing that the obedience response to authority is primarily 'natural' and necessary for human sociality; it enables communities to thrive by working towards the realisation of common goods through unquestioned acceptance of authority by consent. Only secondarily, obedience processes can morph into dysfunctional 'authoritarianism' that thwarts human potential.

Chapter 5 focusses on the social psychology of conformity, a classical topic of social influence. The chapter starts by reviewing a number of experiments that have demonstrated the human need for affiliation and belonging. This establishes the grounds for sociality that is a necessary precondition for human existence rather than a luxury add-on. It proceeds to review Asch’s classical conformity experiments, followed by Moscovici’s demonstrations of the conditions of minority influence. The chapter ends by considering conformity from a cultural psychology view, concluding that deviance and conformity are behavioural responses expressive of social representations, that is, sociocultural locale conditions. As such they are not explained by individual rational choice. The argument is made that conformity and dissident deviance function to maintain and to challenge the current common sense.

Chapter 8 offers a development of thinking about social influence by considering the role of modern mass mediation. The chapter starts by looking at the role of communication in cultivating social representations of the world, both in formal and informal ways. It proceeds by reviewing several hypotheses concerning mass media effects, including diffusion, knowledge gap, cultivation, diegetic prototyping and serial reproduction. The chapter further considers the extended role of mass mediation in agenda setting, priming and framing issues for public consumption. The idea of a 'spiral of silence' best illustrates how mass media effect analysis adds a second level of analysis to the phenomena of social influence: the theory explicitly elaborates the notion of conformity in the context of modern mass mediation. Hence, the chapter asks a question rather than offering the answer: how do media effect theories elaborate social influence simultaneously on two levels, that of interaction and that of mass mediation. For example, how does this tie in with the rediscovery of crowds as 'internet bubbles' and 'echo chambers dominated by conformity bias and motivated reasoning'?