Decision-Making under Uncertainty for Vietnamese Adolescents: Heuristics, Biases, Frameworks, and a Reversibility-Aware Operational Skill Set

The adjacent Layer-I papers (I3.1 major-selection, I3.2 labour-market, I3.3 family integration) each presuppose a meta-skill that the chooser is rarely taught explicitly: how to make a decision under genuine uncertainty when expectedvalue optimisation is not available. This paper synthesises the decision-research literature to provide that meta-skill foundation for Vietnamese learners aged 14–19. Three structurally different decision regimes are distinguished — risk (probabilities approximately known; expected-value optimisation is sound), uncertainty (probabilities unknown; heuristics plus reversibility-aware framing dominate), and genuine ignorance (no model of outcomes; option-creating and minimum-regret are the only defensible moves) — following Knight 1921 and the modern reception of his risk-uncertainty distinction [1], [2]. The paper presents the Kahneman-Gigerenzer dialectic honestly: Kahneman 2011 and the Tversky-Kahneman 1979 prospect-theory programme established the heuristics-and-biases tradition that dominates popular discourse [3], [4], [5], while Gigerenzer 2007 / 2008 and Klein 1998 / 2008 documented that fast-and-frugal heuristics frequently outperform optimisation under realistic information conditions [6], [7], [8], [9], [10]. The replication-crisis evidence is presented without sanitisation: a meaningful fraction of the popularised everyone is biased canon has weakened or failed replication [11], [12], [13], [14], and guidance content built on the strong form of the canon is inheriting an over-claim. Adolescent-specific findings from Reyna-Farley 2006 and Steinberg 2007 / 2008 establish that adolescent decision-making is a developmentally distinct mode in which the gist-versus-verbatim balance and the reward-sensitivity / cognitive-control gap are load-bearing [15], [16], [17], [18]. The cross-cultural evidence [19], [20] places Vietnamese adolescents in a high uncertaintyavoidance, collectivist-leaning context that systematically modifies how the Anglo-American decision-research prescriptions transfer. The paper's central operational contribution is a reversibility-aware framing — irreversible / partially-reversible / reversible — argued to be the load-bearing axis for an adolescent without strong probability calibration. The deliverable is a ranked operational skill set of ten practices ranked by evidence strength, deployability without instruments, and Vietnamesecontext fit. Worked examples cover major-selection, romanticpartner choice, financial decisions, opportunity acceptance, and relationship termination. Per the elix-researches no-cohort scope [21], no empirical validation with Vietnamese adolescents is in plan.