Simple deterministic and complex probabilistic regularities underlying risky choices are acquired in a changing decision context

Beliefs about positive and negative outcome probabilities have been frequently investigated in experience-based risky decision making. However, it has not been clarified how these beliefs emerge and whether they remain persistent if the predictability and complexity of outcome probabilities change across decision contexts. Hence, the present study manipulated these two factors in a variant of the Balloon Analogue Risk Task performed by healthy young adults. In the first and final task phases, outcomes (rewards or balloon bursts) were predictable because of the presence of an underlying regularity. In the middle phase, outcomes were unpredictable because the regularity was absent. The complexity of the regularity differed across the deterministic, probabilistic, and hybrid experimental conditions. In the simple deterministic condition, a repeating sequence of three deterministic regularities perfectly predicted balloon bursts. In the more complex probabilistic condition, a single probabilistic regularity ensured that the probability of balloon bursts increased with each successive pump. In the most complex hybrid condition, a repeating sequence of three different probabilistic regularities increased burst probabilities. Even without informing participants about the presence or absence of the regularity, sensitivity to both the simple deterministic and the most complex hybrid regularities emerged and influenced risk taking. Unpredictable outcomes of the middle phase did not deteriorate the acquired sensitivity to these regularities. When only a single probabilistic regularity was present, predictable and unpredictable outcomes were processed similarly. In conclusion, assuming the reappearance of the initially experienced regularity, the robustness of representations might serve fast adaptation in a volatile decision environment.