This project aims to rigorously develop and empirically test the ETII theory to explain both social and biological aspects of human change, past, present, and future. The core research will be structured around three pillars. (1) Theoretical Model Development: Develop formal theoretical models of long-term gene–culture coevolution to explore the unique features of a coupled inheritance and individuality transition. This includes exploring how the accumulation of group-level cultural variation drives the transition. (2) Empirical Testing and Metric Estimation: Conduct systematic empirical tests using both deep-time and modern datasets to measure movement along the transition. This work requires developing novel methods to estimate the two key transition indices: T_p, the cultural determination of phenotype and T_ω the group determination of fitness. We hope to develop or find unbiased methods to compare cultural and genetic contributions to phenotype for and derive better historical and modern estimates of the strength of culture-driven group selection on human genes. (3) Ethics and Outreach: The ETII framework raises deep ethical challenges, particularly concerning increasing group control over reproduction and potential post-biological evolution. This pillar will integrate ethics research and development alongside the scientific endeavors, ensuring that the evolutionary mechanisms described are examined without moral valence.