Abstract
In a controlled laboratory experiment, we find that participants persist in following a pre-
viously profitable strategy even after being explicitly informed that it is no longer profitable.
Combining experimental manipulations with computational modelling, we isolate a Pavlovian
mechanism underlying this maladaptive persistence: past rewards trigger an automatic attrac-
tion to gambling that can override deliberate choice. This Pavlovian influence intensifies under
uncertainty, suggesting that it extends beyond reward-seeking to include “sign-tracking”—an
attraction to gambling cues themselves, with apparent disregard for expected outcomes. These
findings may help explain investor inertia and, more broadly, excessive risk-taking across mod-
ern digital platforms, from online gambling to cryptocurrency and day trading. They suggest
a two-pronged intervention strategy to mitigate gambling risks: (1) curbing distorted outcome
perceptions (e.g., Losses Disguised as Wins), and (2) reducing playful features and engineered
uncertainty that amplify sign-tracking.