This chapter introduces the dynamics of ecosystems and chaotic systems, providing an accessible overview for readers unfamiliar with complexity theory. Key concepts such as fractals and emergence are defined and applied to social groups through the FLINT model of Factional Leadership, Intergroup Conflict, Norms, and Time, which explains how factions and subgroups form and ferment within a seemingly unified group. This model examines forces driving subgroup differentiation and the challenges of achieving lasting social change because of the need to influence multiple groups simultaneously and overcome resistance. The chapter revisits psychological research on effective activism, underscoring the importance of addressing both conformity and dissent within and between groups. Finally, we discuss empirical methods for analysing these complex dynamics, including network analyses, person-centred analyses, and agent-based modelling, which offer new ways to understand and study the formation and evolution of groups.

We have used the metaphor of onion-peeling to describe the characteristics of insight-focused theories because they seek to peel back layers of experience to reach understanding. Like an onion, human experience reflects a layering: layer upon layer, it builds up around us and influences our lives, sometimes in complex and repetitive ways. Awareness and insight lead to change and optimal functioning. The onion-peeling metaphor is relevant to several key theoretical approaches. In this chapter, we explore two that have been particularly influential in the development of social work thinking: psychodynamic and person-centred approaches. As with the ecosystem collection of theories, both psychodynamic and person-centred approaches have extensive histories and traditions. In this chapter, we draw together core ideas from the psychodynamic and person-centred theories that we think best capture the essence of the onion-peeling tradition.