A key life history trait among human beings, that is, the trait that influences all other life history variables in the standard catalog of life history traits (e.g. average lifespan, body size, length of juvenile period, gestational period, inter-birth intervals, fertility rates, etc.) is brain size and complexity. Within the evolutionary sciences, the most applicable selective forces that influence group mind phenomena come out of the fact that we evolved within group contexts and adapted for group-living. I use lineage fitness theory, sexual conflict theory, multi-level section theory, costly signaling theory, and major transitions in evolution theory, as well as theories of cultural evolution, to illuminate topics in group mind. I argue that they all predict that various levels of group mind phenomena must occur. I also adopt and assume some, but not all, of the claims of “4E cognitive science,” namely that the mind is embodied, enacted, embedded, and extended, but I add to it a 5E account by showing that our understanding of group mind must also be rooted in evolutionary theory. Mind is also an evolved phenomenon. A final background framework I assume and adopt in this book is the so-called predictive-processing framework.