Quantifying Phase Transitions in Human Development and Psychopathology - Dimitris Tsomokos

ABSTRACT How can experience that accumulates gradually give rise to behaviour that abruptly reorganises itself? Active inference can help answer this from first principles. In a minimal two-state POMDP with Dirichlet learning, when we couple parameter learning to action selection (i.e., the chosen strategy decides which evidence is sampled, and that evidence shapes the next choice), the model reduces to a self-consistency equation under a mean-field closure. That equation is formally identical to the mean-field Ising model, so a developmental stage shift becomes a bifurcation condition and the cusp catastrophe long postulated in developmental psychology is derived rather than assumed. We verify this in a balance-scale model that recovers Siegler's classic findings, then extend the same machinery to adolescent depression. In the depression model, we find that onset can be abrupt even under gradual adversity, and recovery is governed by the motivational field rather than cognitive control; this ordering is empirically tested in two large birth cohorts from the UK and US. PRESENTER Dr Dimitris I. Tsomokos currently works on child and adolescent mental health and developmental psychology at the UCL Institute of Education, with a previous research background in theoretical physics (quantum information theory and condensed matter). Google Scholar: https://scholar.google.com/citations?... CHAIR Robert Chis-Ciure Google Scholar: https://scholar.google.com/citations?...