Performative Taste: When Creative Control Changes with Horizon

When aesthetic prediction determines what is generated, exposed, copied, and consumed, accuracy can improve by changing the preferences it purports to learn. We study one operational dimension of creative agency: horizon-dependent causal steering in coupled creator--generator--platform--audience systems. We introduce role-normalized causal steering response (CSR), paired counterfactual twins, individual-level performative taste drift (PTD), and a common-support deployment--shadow gap (DSG). Across 1,000 prespecified configurations with 64 paired seeds each, creators controlled the first post-intervention artifact batch, yet platform CSR overtook creator CSR after a conditional median 13 rounds in the high-feedback regime. Factual-history loss fell from 0.132 to 0.085 while reaching 0.142 on the shadow trajectory; a frozen evaluation-start predictor retained 51\% of this reduction, and PTD reached 0.074. At 96.2\% retained utility, 10\% Shadow Exploration produced 31\% less PTD and 28\% less platform CSR than matched weak personalization, and 41\% less PTD than pure exploitation. The frozen control gives a path-specific environment-alignment reference; outcome plurality remains distinct from agency plurality.